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How-To Tutorials

7018 Articles
article-image-data-types-and-fields
Packt
10 Aug 2015
30 min read
Save for later

Data Types and Fields

Packt
10 Aug 2015
30 min read
In this article by David Studebaker and Christopher Studebaker, authors of the book Programming Microsoft Dynamics™ NAV 2015, explain the design of an application should begin at the simplest level, with the design of the data elements. The type of data our development tool supports has a significant effect on our design. Because NAV is designed for financially-oriented business applications, NAV data types are financially and business oriented. In this article, we will cover many of the data types we use within NAV. For each data type, we will cover some of the more frequently modified field properties and how particular properties, such as Field Class, are used to support application functionality. Field Class is a fundamental property which defines whether the contents of the field are data to be processed or control information to be interpreted. (For more resources related to this topic, see here.) Data types We are going to segregate the data types into several groups. We will first look at Fundamental data types and then at Complex data types. Fundamental data types Fundamental data types are the basic components from which the complex data types are formed. They are grouped into Numeric, String, and Date/Time data types. Numeric data Just like other systems, Microsoft Dynamics NAV 2015 supports several numeric data types. The specifications for each NAV data type are defined for NAV, independent of the supporting SQL Server database rules. However, some data types are stored and handled somewhat differently from a SQL Server point of view than the way they appear to us as NAV developers and users. For more details on the SQL Server-specific representations of various data elements, refer to the Developer and IT Pro Help. Our discussion will focus on NAV representation and handling for each data type. The various numeric data types are as follows: Integer: This is an integer number ranging from -2,147,483,646 to +2,147,483,647 Decimal: This is a decimal number in the range of +/- 999,999,999,999,999.99. Although it is possible to construct larger numbers, errors such as overflow, truncation, or loss of precision might occur. In addition, there is no facility to display or edit larger numbers. Option: This is a special instance of an integer, stored as an integer number ranging from 0 to +2,147,483,647. An option is normally represented in the body of our C/AL code as an option string. We can compare an option to an integer in C/AL rather than using the option string. However, this is not a good practice because it eliminates the self-documenting aspect of an option field. An option string is a set of choices listed in a comma-separated string, one of which is chosen and stored as the current option. Since the maximum length of this string is 250 characters, the practical maximum number of choices for a single option is less than 125. The currently selected choice within the set of options is stored in the option field as the ordinal position of that option within the set. For example, selection of an entry from the option string of red, yellow, and blue would result in the storing of 0 (red), 1 (yellow), and 2 (blue). If red were selected, 0 would be stored in the variable and if blue were selected, 2 would be stored. Quite often, an option string starts with a blank to allow an effective choice of "none chosen". An example of this (blank, Hourly, Daily,…) is as follows: Boolean: A Boolean variable is stored as 1 or 0. In a C/AL code, it is programmatically referred to as True or False, but sometimes, it is referred in properties as Yes or No. Boolean variables may be displayed as Yes or No (language dependent), P or blank, or True or False. BigInteger: 8-byte Integer as opposed to the 4 bytes of Integer. BigIntegers are for very big numbers (from -9,223,372,036,854,775,807 to 9,223,372,036,854,775,807). Char: A numeric code between 0 and 65535 (hexadecimal FFFF) representing a single 16-bit Unicode character. Char variables can operate either as text or numbers. Numeric operations can be done on Char variables. Char variables can also be defined with individual text character values. Char variables cannot be defined as permanent variables in a table; they can only be defined as working storage variables within C/AL objects. Byte: This is a single 8-bit ASCII character with a value ranging from 0 to 255. Byte variables can operate either as text or numbers. Numeric operations can be done on Byte variables. Byte variables can also be defined with individual text character values. Byte variables cannot be defined as permanent variables in a table, but only as working storage variables within C/AL objects. Action: This is a variable returned from a PAGE RUNMODAL function or RUNMODAL (Page) function that specifies what action a user performs on a page. The possible values are OK, Cancel, LookupOK, LookupCancel, Yes, No, RunObject, and RunSystem. ExecutionMode: This specifies the mode in which a session runs. The possible values are Debug or Standard. String data The following are the data types included in String data: Text: This contains any string of alphanumeric characters. In a table, a Text field can be from 1 to 250 characters long. In working storage within an object, a Text variable can be any length if no length is defined. If a maximum length is defined, it must not exceed 1024. NAV 2015 does not require a length to be specified, but if we define a maximum length, it will be enforced. When calculating the length of a record for design purposes (relative to the maximum record length of 8,000 bytes), the full defined field length should be counted. Code: Although the Help says that the length constraints for Code variables are the same as those for text variables, the C/AL Editor enforces length limits of 1 to 250 characters. All of the letters are automatically converted to uppercase when data is entered into a Code variable; any leading or trailing spaces are removed. Date/Time data The following are the data types included in Date/Time data: Date: This contains an integer number, which is interpreted as a date ranging from January 1, 1754 to December 31, 9999. A 0D (numeral zero, letter D) represents an undefined date (stored as a SQL Server DateTime field) that is interpreted as January 1, 1753. According to the Developer and IT Pro Help that, NAV 2015 supports a Date of 1/1/0000 (presumably as a special case for backward compatibility, but it is not supported by SQL Server). A date constant can be written as the letter D preceded by either six digits in the format MMDDYY or eight digits as MMDDYYYY (where M = month, D = day, and Y = year). For example, 011915D or 01192015D both represent January 19, 2015. Later, in DateFormula, we will find D interpreted as day, but here the trailing D is interpreted as the date (data type) constant. When the year is expressed as YY rather than YYYY, the century portion (in this case, 20) is 20 if the two digit year is from 00 to 29, or 19 if the year is from 30 through 99. NAV also defines a special date called the Closing date, which represents the point in time between one day and the next. The purpose of a closing date is to provide a point at the end of a day, after all of the real date- and time-sensitive activity is recorded—the point when accounting closing entries can be recorded. Closing entries are recorded, in effect, at the stroke of midnight between two dates—this is the date of closing accounting books, and it is designed so that one can include or exclude, at the user's option, closing entries in various reports. When sorted by date, the closing date entries will get sorted after all normal entries for a day. For example, the normal date entry for December 31, 2015 would display as 12/31/15 (depending on the date format masking), and the closing date entry would display as C12/31/15. All of the C12/31/15 ledger entries would appear after all normal 12/31/15 ledger entries. The following screenshot shows two 2014 closing date entries mixed with normal entries from December 2015 and January through April 2015. (This data is from Cronus demo. The 2014 Closing entries have an "Opening Entry" description, which shows that these were the first entries for the demo data in the respective accounts. This is not a normal set of production data.) Time: This contains an integer number, which is interpreted on a 24-hour clock, in milliseconds plus 1, from 00:00:00 to 23:59:59:999. A 0T (numeral zero, letter T) represents an undefined time and is stored as 1/1/1753 00:00:00.000. DateTime: This represents a combined Date and Time, stored in Coordinated Universal Time (UTC), and it always displays local time (that is, the local time on our system). DateTime fields do not support NAV "Closing" dates. DateTime is helpful for an application that must support multiple time zones simultaneously. DateTime values can range from January 1, 1754 00:00:00.000 to December 31, 9999 23:59:59.999, but dates earlier than January 1, 1754 cannot be entered (don't test with dates late in 9999 as an intended advance to the year 10000 won't work). Assigning a date of 0DT will yield an undefined or blank DateTime. Duration: This represents the positive or negative difference between two DateTime values, in milliseconds, stored as a BigInteger. Durations are automatically output in the text format as DDD days HH hours MM minutes SS seconds. Complex data types Each complex data type consists of multiple data elements. For ease of reference, we will categorize them into several groups of similar types. Data structure The following data types are in the data structure group: File: This refers to any standard Windows file outside the NAV database. There is a reasonably complete set of functions to allow to create, delete, open, close, read, write, and copy (among other things) data files. For example, we could create our own NAV routines in C/AL to import or export data from or to a file that had been created by some other application. With the three-tier architecture of NAV 2015, business logic runs on the server and not the client. We need to keep this in mind any time we refer to local external files because they will be on the server by default. Use of Universal Naming Convention (UNC) paths can make this easier to manage. Record: This refers to a single data row within a NAV table that consists of individual fields. Quite often, multiple variable instances of a Record (table) are defined in working storage to support a validation process, allowing access to different records within the table at one time in the same function. Objects Page, Report, Codeunit, Query, and XMLPort, each represents an object data type. Object data types are used when there is a need to refer to an object or a function in another object. Examples: Invoking a Report or an XMLPort from a Page or a Report Calling a function for data validation or processing is coded as a function in a Table or a Codeunit Automation The following are Automation data types. (these are not supported by the NAV Web client.) OCX and Automation data types are supported in NAV 2015 for backward compatibility only: OCX: This allows the definition of a variable that represents and allows access to an ActiveX or OCX custom control. Such a control is typically an external application object that we can invoke from our NAV object. Automation: This allows us to define a variable that we can access similar to an OCX. The application must act as an Automation Server and be registered with the NAV client or server that calls it. For example, we can interface from NAV into the various Microsoft Office products (Word, Excel, and so on) by defining them in Automation variables. DotNet: This allows us to define a variable for .NET Framework interface types within an assembly. It supports accessing .NET Framework type members, including methods, properties, and constructors from C/AL. These can be members of the global assembly cache or custom assemblies. Input/Output The following are the Input/Output data types: Dialog: This supports the definition of a simple user interface window without the use of a Page object. Typically, Dialog windows are used to communicate processing progress or allow a brief user response to a go/no-go question, though this latter use could result in bad performance due to locking. There are other user communication tools as well, but they do not use a Dialog type data item. InStream and Outstream: These allow us to read from and write to external files, BLOBS, and objects of the Automation and OCX data types. DateFormula DateFormula provides for the definition and storage of a simple, but clever, set of constructs to support the calculation of runtime-sensitive dates. A DateFormula is stored in a nonlanguage dependent format, thus supporting multilanguage functionality. A DateFormula is a combination of: Numeric multipliers (for example, 1, 2, 3, 4, and so on) Alpha time units (all must be in uppercase) D for a day W for a week WD for day of the week, that is, from day 1 to day 7 (either in the future or in the past but not today). Monday is day 1 and Sunday is day 7. M for calendar month Y for year CM for current month, CY for current year, CW for current week Math symbols interpretation + (plus) as in CM + 10D means the Current Month end plus 10 Days (in other words, the tenth of the next month) – (minus) as in (-WD3) means the date of the previous Wednesday (which is the 3rd day of the past week). Positional notation (D15 means the 15th day of the month and 15D means 15 days) Payment Terms for Invoices support full use of DateFormula. All DateFormula results are expressed as a date based on a reference date. The default reference date is the system date and not the Work Date. Here are some sample DateFormulas and their interpretations (displayed dates are based on the US calendar) with a reference date of July 10, 2015, a Friday: CM is the last day of Current Month, 07/31/15 CM + 10D is the tenth of the next month, 08/10/15 WD6 is the next sixth day of the week, 07/11/15 WD5 is the next fifth day of the week, 07/17/15 CM – M + D is the end of the current month minus one month plus one day, 07/01/15 CM – 5M is the end of the current month minus five months, 02/28/15 Let us take the opportunity to use the DateFormula data type to learn a few NAV development basics. We will do so by experimenting with some hands-on evaluations of several DateFormula values. We will create a table to calculate dates using DateFormula and Reference Dates. To do this, navigate to Tools | Object Designer | Tables. Then, click on the New button and define the fields shown in the following screenshot. Save it as Table 50009, named Date Formula Test. After we are done with this test, we will save this table for some later testing. Now, we will add some simple C/AL code to our table so that when we enter or change either the Reference Date or the DateFormula data, we can calculate a new result date. First, access the new table via the Design button. Then, go to the global variables definition form through the View menu option, the C/AL Globals sub-option, and finally, choose the Functions tab. Type in our new function name as CalculateNewDate on the first blank line, as shown in the following screenshot, and then exit (by means of the Esc key) from this form back to the list of data fields: From the Table Designer form that displays the list of data fields, either press F9 or click on the C/AL Code icon: This will take us to the following screen, where we can see all of the field triggers plus the trigger for the new function that we just defined. The table triggers will not be visible, unless we scroll up to show them. Note that our new function was defined as a LOCAL function. This means that it cannot be accessed from another object unless we change it to a GLOBAL function. Since our goal now is to focus on experimenting with the DateFormula, we will not go into detail and explain the logic of what we are creating. The logic that we're going to code is as follows: When an entry is made (new or changed) in either the "Reference Date" field or in the "Date Formula to Test field", invoke the CalculateNewDate function to calculate a new “Result Date” value based on the entered data. First, you need to create the logic within our new function, CalculateNewDate(), to evaluate and store a Date Result based on the DateFormula and Reference Date that you enter into the table. Just copy the C/AL code exactly as shown in the following screenshot, exit, compile, and save the table: If you get an error message of any type when you close and save the table, you probably have not copied the C/AL code exactly as it is shown in the screenshot. (also shown below for ease of copying.) CalculateNewDate;"Date Result" := CALCDATE("Date Formula to Test","Reference Date for Calculation"); This code will cause the CalculateNewDate()function to be called via the OnValidate trigger when an entry is made in either the Reference Date for Calculation or the Date Formula to Test fields. The function will place the result in the Date Result field. The use of an integer value in the redundantly named Primary Key field allows us to enter any number of records into the table (by manually numbering them 1, 2, 3, and so forth). Let's experiment with several different date and date formula combinations. We will access the table via the Run button. This will cause NAV to generate a default format page and run it in the Role Tailored Client. Enter a Primary Key value of 1 (one). In Reference Date for Calculation, enter either an upper or lower case T for Today and the system date. The same date will appear in the Date Result field because at this point, no Date Formula has been entered. Now, enter 1D (number 1 followed by uppercase or lowercase D (C/SIDE will make it uppercase) in the Date Formula to Test field. We will see that the Date Result field contents are changed to be one day beyond the date in the Reference Date for Calculation field. Now, for another test entry, start with a 2 in the Primary Key field. Again, enter the letter T (for Today) in the Reference Date for Calculation field, and enter the letter W (for Week) in the Date Formula to Test field. We will get an error message telling us that our formulas should include a number. Make the system happy and enter 1W. We will now see a date in the Date Result field that is one week beyond our system date. Set the system's Work Date to a date in the middle of a month. Start another line with the number 3 as the Primary Key, followed by a W (for Work Date) in the Reference Date for Calculation field. Enter cm (or CM or cM or Cm, it doesn't matter) in the Date Formula to Test field. Our result date will be the last day of our Work Date month. Now, enter another line using the Work Date, but enter a formula of –cm (the same as before but with a minus sign). This time, our result date will be the first day of our Work Date month. Note that the DateFormula logic handles month end dates correctly, including a leap year. Try starting with a date in the middle of February 2016 to confirm this. The following screen shows the Date Formula Test window: Now, enter another line with a new Primary Key. Skip over the Reference Date for Calculation field and just enter 1D in the Date Formula to Test field. So, what happens when you do this? We get an error message stating that "You cannot base a date calculation on an undefined date." In other words, NAV cannot make the requested calculation without a Reference Date. Before we put this function into production, we want our code to check for a Reference Date before calculating. We could default an empty date to the System Date or the Work Date and avoid this particular error. The preceding and following screenshots show different sample calculations. Build on these and then experiment. We can create a variety of different algebraic date formulae and get some very interesting results. One NAV user has due dates on Invoices for the tenth of the next month. Invoices are dated at various times during the month than they are actually printed. By using the DateFormula of CM + 10D, the due date is always automatically calculated to be the tenth of the next month. Don't forget to test with WD (weekday), Q (quarter), and Y (year) as well as D (day), W (week), and M (month). For our code to be language independent, we should enter the date formulae with < > delimiters around them (for example, <1D+1W>). NAV will translate the formula into the correct language codes using the installed language layer. Although our focus for the work we just completed was the Date Formula data type, we've accomplished a lot more than simply learning about that one data type: We created a new table just for the purpose of experimenting with a C/AL feature that we might use. This is a technique that comes in handy when we are learning a new feature or trying to decide how it works or how we might use it. We put some critical OnValidate logic in the table. When data is entered in one area, the entry is validated and, if valid, the defined processing is done instantly. We created a common routine as a new LOCAL function. This function is then called from all the places to which it applies. We did our entire test with a table object and a default tabular page that is automatically generated when we Run a table. We didn't have to create a supporting structure to do our testing. Of course, when we design a change to a complicated existing structure, we will have a more complicated testing scenario. One of our goals will always be to simplify our testing scenarios, both to minimize the setup effort and to keep our test narrowly focused on the specific issue. Finally, and most specifically, we saw how NAV tools make a variety of relative date calculations easy. These are very useful in business applications, many aspects of which are date centered. References and other data types The following data types are used for advanced functionality in NAV, sometimes supporting an interface with an external object: RecordID: This contains the object number and primary key of a table. RecordRef: This identifies a row in a table, a record. RecordRef can be used to obtain information about the table, the record, the fields in the record, and the currently active filters on the table. FieldRef: This identifies a field in a table; thus, it allows access to the contents of that field. KeyRef: This identifies a key in a table and the fields in that key. Since the specific record, field, and key references are assigned at runtime, RecordRef, FieldRef, and KeyRef are used to support logic which can run on tables that are not specified at design time. This means that one routine built on these data types can be created to perform a common function for a variety of different tables and table formats. Variant: This defines variables that are typically used to interface with Automation and OCX objects. Variant variables can contain data of various C/AL data types to pass them to an Automation or OCX object as well as external Automation data types that cannot be mapped to C/AL data types. TableFilter: For variables which can only be used for setting security filters from the Permissions table. Transaction Type: This has optional values of UpdateNoLocks, Update, Snapshot, Browse, and Report that define SQL Server behavior for a NAV Report or XMLport transaction from the beginning of the transaction. BLOB: This can contain either specially formatted text, a graphic in the form of a bitmap, or other developer-defined binary data up to 2 GB in size. The term Binary Large Object (BLOB). BLOBs can only be included in tables and not used to define working storage Variables. Refer to Developer and IT Pro Help for additional information. BigText: This can contain large chunks of text up to 2 GB in size. BigText variables can only be defined in the working storage within an object, but they cannot be included in tables. BigText variables cannot be directly displayed or seen in the debugger. There is a group of special functions that can be used to handle BigText data. Refer to Developer and IT Pro Help for additional information. To handle text strings in a single data element that are greater than 250 characters in length, use a combination of BLOB and BigText variables. GUID: This is used to assign a unique identifying number to any database object. Globally Unique Identifier (GUID), a 16-byte binary data type that is used for unique global identification of records, objects, and so on. GUID is generated by an algorithm developed by Microsoft. TestPage: This is used to store a test page, which is a logical representation of a page that does not display a user interface. Test pages are used when you do NAV application testing using the automated testing facility that is part of NAV. Data type usage About forty percent of the data types can be used to define the data either stored in tables or in working storage data definitions (that is, in a Global or Local data definition within an object). Two data types, BLOB and TableFilter, can only be used to define table-stored data, but not working storage data. About sixty percent of the data types can only be used for working storage data definitions. The following list shows which data types can be used for table (persisted) data fields and which ones can be used for working storage (variable) data: FieldClass property options Almost all data fields have a FieldClass property. FieldClass has as much effect on the content and usage of a data field as the data type; in some instances, it has more effect. Now we'll discuss the FieldClass property options now. FieldClass – Normal When the FieldClass is Normal, the field will contain the type of application data that's typically stored in a table—the contents we would expect based on the data type and various properties. FieldClass – FlowField FlowFields must be dynamically calculated. FlowFields are virtual fields stored as metadata; they do not contain data in the conventional sense. A FlowField contains the definition of how to calculate (at runtime) the data that the field represents and a place to store the result of that calculation. Generally, the Editable property for a FlowField is set to No.. Depending on the CalcFormula method, this could be a value, a reference lookup, or a Boolean. When the CalcFormula method is Sum, the FieldClass connects a data field to a previously defined SumIndexField in the table defined in the CalcFormula. The FlowField processing speed will be significantly affected by the key configuration of the table being processed. While we must be careful not to define extra keys, having the right keys defined will have a major effect on system performance and thus, on user satisfaction. A FlowField value is always 0, blank, or false, unless it has been calculated. If a FlowField is displayed directly on a page, it is calculated automatically when the page is rendered. FlowFields are also automatically calculated when they are the subject of predefined filters as part of the properties of a data item in an object. In all other cases, a FlowField must be forced to calculate using the C/AL RecordName.CALCFIELDS(FlowField1, [FlowField2],...) function or by the use of the SETAUTOCALCFIELDS function. This is also true if the underlying data is changed after the initial display of a page (that is, the FlowField must be recalculated to take a data change into account). Because a FlowField does not contain actual data, it cannot be used as a field in a key. In other words, we cannot include a FlowField as part of a key. In addition, we cannot define a FlowField that is based on another FlowField, except in special circumstances. When a field has its FieldClass set to FlowField, another directly associated property becomes available—CalcFormula. (Conversely, the AltSearchField, AutoIncrement, and TestTableRelation properties disappear from view when FieldClass is set to FlowField). The CalcFormula method is the place where we can define the formula for calculating the FlowField. On the CalcFormula property line, there is an ellipsis button. Clicking on that button will bring up the following screen: Click on the drop-down button to show the seven FlowField methods: The seven FlowFields are described in the following table: FlowField Method Field data type   Calculated value as it applies to the specified set of data within a specific column (field) in a table   Sum Decimal The sum total Average Decimal The average value (the sum divided by the row count) Exist Boolean Yes or No / True or False - does an entry exist? Count Integer The number of entries that exist Min Any The smallest value of any entry Max Any The largest value of any entry Lookup Any The value of the specified entry The Reverse Sign control allows us to change the displayed sign of the result for FlowField types Sum and Average only; the underlying data is not changed. If a Reverse Sign is used with the FlowField type Exists, it changes the effective function to does not Exist. Table and Field allow us to define the Table and the Field within that table to which our Calculation Formula will apply. When we make the entries in our Calculation Formula screen, no validation checking is done by the compiler to check whether we have chosen an eligible table and field combination. This checking doesn't occur until runtime. Therefore, when we create a new FlowField, we should test it as soon as we have defined it. The last, but by no means the least significant component of the FlowField calculation formula is the Table Filter. When we click on the ellipsis in the table filter field, the window shown in the following screenshot will appear: When we click on the Field column, we will be invited to select a field from the table that was entered into the Table field earlier. The Type field choice will determine the type of filter. The Value field will have the filter rules defined on this line, which must be consistent with the Type choices described in the following table: Filter type Value Filtering action OnlyMax- Limit Values- Filter Const   A constant which will be defined in the Value field This uses the constant to filter for equally valued entries     Filter   A filter that will be spelled out as a literal in the Value field This applies the filter expression from the Value field     Field   A field from the table within which the FlowField exists This uses the contents of the specified field to filter equally valued entries False False     If the specified field is a FlowFilter and the OnlyMaxLimit parameter is True, then the FlowFilter range will be applied on the basis of only having a MaxLimit, that is, having no bottom limit. This is useful for the date filters for the Balance Sheet data. (Refer to Balance at Date field in the G/L Account table for an example) True False     This causes the contents of the specified field to be interpreted as a filter (See Balance at Date field in the G/L Account table for an example) True or False True FieldClass – FlowFilter FlowFilters control the calculation of FlowFields in the table (when the FlowFilters are included in the CalcFormula). FlowFilters do not contain permanent data, but instead, they contain filters on a per-user basis, with the information stored in that user's instance of the code that is being executed. A FlowFilter field allows a filter to be entered at a parent record level by the user (for example, G/L Account) and applied (through the use of FlowField formulas, for example) to constrain what child data (for example, G/L Entry records) is selected. A FlowFilter allows us to provide flexible data selection functions to the users. The user does not need to have a full understanding of the data structure to apply filtering in intuitive ways to both the primary data table and the subordinate data. Based on our C/AL code design, FlowFilters can be used to apply filtering on multiple tables that are subordinate to a parent table. Of course, it is our responsibility as developers to make good use of this tool. As with many C/AL capabilities, a good way to learn more is by studying standard code designed by the Microsoft developers of NAV and then experimenting. A number of good examples on the use of FlowFilters can be found in the Customer (Table 18) and Item (Table 27) tables. In the Customer table, some of the FlowFields using FlowFilters are Balance, Balance (LCY), Net Change, Net Change (LCY), Sales (LCY), and Profit (LCY) where LCY stands for local currency. The Sales (LCY) FlowField FlowFilter usage is shown in the following screenshot: Similarly constructed FlowFields using FlowFilters in the Item table include Inventory, Net Invoiced Qty., Net Change, Purchases (Qty.) as well as other fields. Throughout the standard code, there are FlowFilters in most of the master table definitions; there are the Date Filters and Global Dimension Filters (global dimensions are user-defined codes that facilitate the segregation of accounting data by groupings such as divisions, departments, projects, customer type, and so on). Other FlowFilters that are widely used in the standard code related to Inventory activity such as Location Filter, Lot No. Filter, Serial No. Filter, and Bin Filter. The following pair of images shows two fields from the Customer table, both with a Data Type of Date. On the left side of the screenshot is the Last Date Modified field (FieldClass of Normal) and on the right side of the screenshot is the Date Filter field (FieldClass of FlowFilter). It's easy to see that the properties of the two fields are very similar, except for the properties that differ because one is a Normal field and the other is a FlowFilter field. Summary In this article, we focused on the basic building blocks of the NAV data structure: fields and their attributes. We reviewed the types of data fields, properties, and trigger elements for each type of field. We walked through a number of examples to illustrate most of these elements though we had postponed the exploration of triggers until later, when we had more knowledge of C/AL. We covered Data Type and FieldClass, properties which determine what kind of data can be stored in a field. Resources for Article: Further resources on this subject: Customization in Microsoft Dynamics CRM [article] What is BI and What are BI Tools for Microsoft Dynamics GP? [article] Learning MS Dynamics AX 2012 Programming [article]
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Packt
10 Aug 2015
20 min read
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Updating and building our masters

Packt
10 Aug 2015
20 min read
In this article by John Henry Krahenbuhl, the author of the book, Axure Prototyping Blueprints, we determine that with modification, we can use all of the masters from the previous community site. To support our new use cases, we need additional registration variables, a master to support user registration, and interactions for the creation of, and to comment on, posts. Next we will create global variables and add new masters, as well as enhance the design and interactions for each master. (For more resources related to this topic, see here.) Creating additional global variables Based on project requirements, we identified that nine global variables will be required. To create global variables, on the main menu click on Project and then click on Global Variables…. In the Global Variables dialog, perform the following steps: Click the green + sign and type Email. Click on the Default Value field and type songwriter@test.com. Repeat step 1 eight more times to create additional variables using the following table for the Variable Name and Default Value fields: Variable Name Default Value Password Grammy UserEmail   UserPassword   LoggedIn No TopicIndex 0 UserText   NewPostTopic   NewPostHeadline   Click on OK. With our global variables created, we are now ready to create new masters, as well as update the design and interactions for existing masters. We will start by adding masters to the Masters pane. Adding masters to the Masters pane We will add a total of two masters to the Masters pane. To create our masters, perform the following steps: In the Masters pane, click on the, Add Master icon ,type PostCommentary and press Enter. Again, in the Masters pane, click on the Add Master icon , type NewPost and press Enter. In the same Masters pane, right-click on the icon next to the Header master, mouse over Drop Behavior and click on Lock to Master Location. We are now ready to remodel the existing masters and complete the design and interactions for our new masters. We will start with the Header master. Enhancing our Header master Once completed, the Header master will look as follows: To update the Header master, we will add an ErrorMessage label, delete the Search widgets, and update the menu items. To update widgets on the Header master, perform the following steps: In the Masters pane, double-click on the icon  next to the Header master to open in the design area. In the Widgets pane, drag the Label widget  and place it at coordinates (730,0). Now, select the Text Field widget and type Your email or password is incorrect.. In the Widget Interactions and Notes pane, click in the Shape Name field and type ErrorMessage. In the Widget Properties and Style pane, with the Style tab selected, scroll to Font and perform the following steps: Change the font size to 8. Click on the down arrow next to the Text Color icon . In the drop-down menu, in the # text field, enter FF0000. In the toolbar, click on the checkbox next to Hidden. Click on the EmailTextField at coordinates (730,10). If text is displayed on the text field, right-click and click Edit Text. All text on the widget will be highlighted, click on Delete. In the Widget Properties and Style pane, with the Properties tab selected, scroll to Text Field and perform the following steps: Next to Hint Text, enter Email. Click Hint Style. In the Set Interaction Styles dialog box, click on the checkbox next to Font Color. Click on the down arrow next to the Text Color icon . In the drop-down menu, in the # text field, enter 999999. Click on OK. Click on the PasswordTextField at coordinates (815,10). If text is displayed on the text field, right-click and click on Edit Text. All text on the widget will be highlighted, press Delete. In the Widget Properties and Style pane, with the Properties tab selected, scroll to Text Field and perform the following steps: Click on the drop-down menu next to Type and select Password. Next to Hint Text, enter Password. Click on Hint Style. In the Set Interaction Styles dialog box, click on the checkbox next to Font Color. Click on the down arrow next to the Text Color icon . In the drop-down menu, in the # text field, enter 999999. Click on OK. Click on the SearchTextField at coordinates (730,82) and then on Delete. Click on the SearchButton at coordinates (890,80) and then on Delete. Next, we will convert all the Log In widgets into a dynamic panel named LoginDP. The LoginDP will allow us to transition between states and show different content when a user logs in. To create the LoginDP, in our header, select the following widgets: Named Widget Coordinates ErrorMessage (730,0) EmailTextField (730,10) PasswordTextField (815,10) LogInButton (894,10) NewUserLink (730,30) ForgotLink (815,30) With the preceding six widgets selected, right-click and click Convert to Dynamic Panel. In the Widget Interactions and Notes pane, click on the Dynamic Panel Name field and type LogInDP. All the Log In widgets are now on State1 of the LogInDP. We will now add widgets to State2 for the LogInDP. With the Log In widgets converted into the LogInDP, we will now add and design State2. In the Widget Manager pane, under the LogInDP, right-click on State1, and in the menu, click on Add State. Click on the State icon beside  State2 twice, to open in the design area. Perform the following steps: In the Widgets pane, drag the Label widget  and place it at coordinates (0,13) and do the these steps: Type Welcome, email@test.com. In the Widget Interactions and Notes pane, click in the Shape Name field and type WelcomeLabel. In the Widget Properties and Style pane, with the Style tab selected scroll to Font, change the font size to 9, and click on the Italic icon . In the Widgets pane, drag the Button Shape widget  and place it at coordinates (164,10). Type Log Out. In the toolbar, change w: to 56 and h: to 16. In the Widget Interactions and Notes pane, click on the Shape Name field and type LogOutButton. To complete the design of the Header master, we need to rename the menu items on the HzMenu. In the Masters pane, double-click on the Header master to open in the design area. Click on the HzMenu at coordinates (250,80). Perform the following steps: Click on the first menu item and type Random Musings. In the Widget Interactions and Notes pane, click on the Menu Item Name field and type RandomMusingsMenuItem. Click on Case 1 under the OnClick event and press the Delete key. Click on Create Link…. In the pop-up sitemap, click on Random Musings. Again, click on the first menu item and type Accolades and News. In the Widget Interactions and Notes pane, click on the Menu Item Name field and type AccoladesMenuItem. Click on Case 1 under the OnClick event and press the Delete key. Click on Create Link…. In the pop-up sitemap, click on Accolades and News. Click on the first menu item and type About. In the Widget Interactions and Notes pane, click on the Menu Item Name field and type AboutMenuItem. Click on Case 1 under the OnClick event and press the Delete key. Click on Create Link…. In the pop-up sitemap, click on About. We will now create a registration lightbox that will be shown when the user clicks on the NewUserLink. To display a dynamic panel in a lightbox, we will use the OnShow action with the option treat as lightbox set. We will use the Registration dynamic panel's Pin to Browser property to have the dynamic panel shown in the center and middle of the window. Learn more at http://www.axure.com/learn/dynamic-panels/basic/lightbox-tutorial. In the Masters pane, double-click on the icon  next to the Header master to open in the design area. In the Widgets pane, drag the Dynamic Panel widget  and place it at coordinates (310,200). In the toolbar, change w: to 250, h: to 250, and click on the Hidden checkbox. In the Widget Interactions and Notes pane, click on the Dynamic Panel Name field and type RegistrationLightBoxDP. In the Widget Manager pane with the Properties tab selected, click on Pin to Browser. In the Pin to Browser dialog box, click on the checkbox next to Pin to browser window and click on OK. In the Widget Manager pane, under the RegistrationLightBoxDP, click on the State icon  beside State1 twice to open in the design area. In the Widgets pane, drag the Rectangle widget  and place it at coordinates (0,0). In the Widget Interactions and Notes pane, click on the Shape Name field and type BackgroundRectangle. In the toolbar, change w: to 250 and h: to 250. Again in the Widgets pane, drag the Heading2 widget  and place it at coordinates (25,20). With the Heading2 widget selected, type Registration. In the toolbar, change w: to 141 and h: to 28. In the Widget Interactions and Notes pane, click on the Shape Name field and type RegistrationHeading. Repeat steps 8-10 to complete the design of the RegistrationLightBoxDP using the following table (* if applicable): Widget Coordinates Text* (Shown on Widget) Width* (w:) Height* (h:) Name field (In the Widget Interactions and Notes pane)   Label (25,67) Enter Email     EnterEmailLabel   Text Field (25,86)       EnterEmailField   Label (25,121) Enter Password     EnterPasswordLabel   Text Field (25,140)       EnterPasswordField   Button Shape (25,190) Submit 200 30 SubmitButton Click on the EnterEmailField text field at coordinates (25,86). In the Widget Properties and Style pane, with the Properties tab selected, scroll to Text Field and perform the following steps: Next to Hint Text, enter Email. Click on Hint Style. In the Set Interaction Styles dialog box, click on the checkbox next to Font Color. Click on the down arrow next to the Text Color icon . In the drop-down menu, in the # text field, enter 999999. Click on OK. Click on the EnterPasswordField text field at coordinates (25,140). In the Widget Properties and Style pane, with the Properties tab selected, scroll to Text Field and perform the following steps: Click on the drop-down menu next to Type and select Password. Next to Hint Text, enter Password. Click on Hint Style. In the Set Interaction Styles dialog box, click on the checkbox next to Font Color. Click on the down arrow next to the Text Color icon . In the drop-down menu, in the # text field, enter 999999. Click on OK. With the updates completed for the Header master, we are now ready to define the interactions. Refining the interactions for our Header master We will need to add additional interactions for Log In and Registration on our Header master. Interactions with our Header master will be triggered by the following named widgets and events: Dynamic Panel State Widget Event LoginDP State1 LoginButton OnClick LoginDP State1 NewUserLink OnClick LoginDP State1 ForgotLink OnClick LoginDP State2 LogOutButton OnClick RegistrationLightBoxDP State1 SubmitButton OnClick We will now define the interactions for each widget, starting with LoginButton. Defining interactions for the LoginButton When the LoginButton is clicked, the OnClick event will evaluate if the text entered in the EmailTextField and PasswordTextField equals the e-mail and password variable values. If the variables are valid, LoginDP will be set to State2 and text on the WelcomeLabel will be updated. If the variables values are not equal, we will show an error message. We will define these actions by creating two cases: ValidateUser and ShowErrorMessage. Validating the user's email and password To define the ValidateUser case for the OnClick interaction, open the LogInDP State1 in the design area. Click on the LogInButton at coordinates (164,10). In the Widget Interactions and Notes pane with the Interactions tab selected, click on Add Case…. A Case Editor dialog box will open. In the Case Name field, type ValidateUser. In the Case Editor dialog, perform the following steps: You will see the Condition Builder window similar to the one shown in the following screenshot after the first and second conditions are defined: Create the first condition. Click on the Add Condition button. In the Condition Builder dialog box, in the outlined condition box, perform the following steps: In the first dropdown, select text on widget. In the second dropdown, select EmailTextField. In the third dropdown, select equals. In the fourth dropdown, select value. In the fifth dropdown, select [[Email]]. Click the green + sign. Create the second condition. Click on the Add Condition button. In the Condition Builder dialog box, in the outlined condition box, perform the following steps: In the first dropdown, select text on widget. In the second dropdown, select PasswordTextField. In the third dropdown, select equals. In the fourth dropdown, select value. In the fifth dropdown, select [[Password]]. Click on OK. Once the following three actions are defined, you should see the Case Editor similar to the one shown in the following screenshot: Create the first action. To set panel state for the LogInDP dynamic panel, perform the following steps: Under Click to add actions, scroll to the Dynamic Panels drop-down menu and click on Set Panel State. Under Configure actions, click on the checkbox next to LoginDP. Next to Select the state, click on the dropdown and select State2. Create the second action. To set text for the WelcomeLabel, perform the following steps: Under Click to add actions, scroll to the Widgets drop-down menu and click on Set Text. Under Configure actions, click the checkbox next to WelcomeLabel. Under Set text to, click on the dropdown and select value. In the text field, enter Welcome, [[Email]]. Create the third action. To set value of the LoggedIn variable, perform the following steps: Under Click to add actions, scroll to the Variables drop-down menu and click on Set Variable Value. Under Configure actions, click on the checkbox next to LoggedIn. Under Set variable to, click on the first dropdown and click on value. In the text field, enter [[Email]]. Click on OK. With the ValidateUser case completed, next we will create the ShowErrorMessage case. Creating the ShowErrorMessage case To create the ShowErrorMessage case, in the Widget Interactions and Notes pane with the Interactions tab selected, click on Add Case…. A Case Editor dialog box will open. In the Case Name field, type ShowErrorMessage. Create the action. To show the ErrorMessage label, perform the following steps: Under Click to add actions, scroll to the Widgets dropdown, click on the Show/Hide dropdown and click on Show. Under Configure actions, under LoginDP dynamic panel, click on the checkbox next to ErrorMessage. Click on OK. Next, we will enable the interaction for the NewUserLink. Enabling interaction for the NewUserLink When the NewUserLink is clicked, the OnClick event will show the RegistrationLightBox dynamic panel as a lightbox, as shown in the following screenshot: With the LogInDP State1 still opened in the design area, click on the NewUserLink at coordinates (0,30). To enable the OnClick event in the Widget Interactions and Notes pane with the Interactions tab selected, click on Add Case…. A Case Editor dialog box will open. In the Case Name field, type ShowLightBox. Now, create the action; to show the RegistrationLightBox, perform the following steps: Under Click to add actions, scroll to the Widgets dropdown, click on the Show/Hide dropdown, and click on Show. Under Configure actions, click on the checkbox next to RegistrationLightBoxDP. Next go to More options, click on the dropdown and select treat as lightbox. Click on OK. Next, we will activate interactions for the ForgotLink. Activating interactions for the ForgotLink When the ForgotLink is clicked, the OnClick event will show the RegistrationLightBox dynamic panel as a lightbox, the RegistrationHeading text will be updated to display Forgot Password? and the EnterPassworldLabel, as well as the EnterPasswordField, will be hidden. To enable the OnClick event, in the Widget Interactions and Notes pane with the Interactions tab selected, click on Add Case…. A Case Editor dialog box will open. In the Case Name field, type ShowForgotLB. In the Case Editor dialog, perform the following steps: Create the first action; to show the RegistrationLightBox, perform the following steps: Under Click to add actions, scroll to the Widgets dropdown, click on the Show/Hide dropdown and click on Show. Under Configure actions, click on the checkbox next to RegistrationLightBoxDP. Next, go to More options, click on the dropdown and select treat as lightbox. Create the second action; to set text for the RegistrationHeading, perform the following steps: Under Click to add actions, scroll to the Widgets drop-down menu and click on Set Text. Under Configure actions, click on the checkbox next to RegistrationHeading. Under Set text to, click on the dropdown and select value. In the text field, enter Forgot Password?. Create the third action; to hide the EnterPasswordLabel and EnterPasswordField, perform the following steps: Under Click to add actions, scroll to the Widgets dropdown, click on the Show/Hide dropdown, and click on Hide. Under Configure actions, under RegistrationLightBoxDP, click on the checkboxes next to EnterPasswordLabel and EnterPasswordField. Click on OK. We have now completed the interactions for State1 of LoginDP. Next, we will facilitate interactions for the LogOutButton. Facilitating interactions for the LogOutButton When the LogOutButton is clicked, the OnClick event will perform the following actions: Hide the ErrorMessage on the LoginDP State1 Set text for PasswordTextField and EmailTextField Set panel state for LoginDP to State1 Set variable value for LoggedIn To enable the OnClick event, open the LogInDP State2 in the design area. Click on the LogInOut at coordinates (164,10). In the Widget Interactions and Notes pane, with the Interactions tab selected, click on Add Case…. A Case Editor dialog box will open. In the Case Name field, type LogOut. In the Case Editor dialog, perform the following steps: Create the first action; to hide the ErrorMessage, perform the following steps: Under Click to add actions, scroll to the Widgets dropdown, click on the Show/Hide dropdown, and click on Hide. Under Configure actions, under LoginDP, click on the checkbox next to ErrorMessage. Create the second action; to set text for the PasswordTextField and EmailTextField, perform the following steps: Under Click to add actions, scroll to the Widgets drop-down menu and click on Set Text. Under Configure actions, click the checkbox next to PasswordTextField. Under Set text to, click the dropdown and select value. In the text field, clear any text shown. Under Configure actions, click the checkbox next to EmailTextField. Under Set text to, click on the dropdown and select value. In the text field, enter Email. Create the third action; to set panel state for the LogInDP dynamic panel, perform the following steps: Under Click to add actions, scroll to the Dynamic Panels drop-down menu and click on Set Panel State. Under Configure actions, click on the checkbox next to LoginDP. Next to Select the state, click on the dropdown and select State1. Create the fourth action. To set variable value of LoggedIn, perform the following steps: Under Click to add actions, scroll to the Variables drop-down menu and click on Set Variable Value. Under Configure actions, click on the checkbox next to LoggedIn. Under Set variable to, click on the first dropdown and click on value. In the text field, enter No. Click on OK. We have now completed interactions for State2 of the LoginDP. Next, we will construct interactions for the RegistrationLightBoxDP. Constructing interactions for the RegistrationLightBoxDP When the LoginButton is clicked, the OnClick event hides RegistrationLightBoxDp and sets the Email and Password variable values to the text entered in the EnterEmailField and EnterPasswordField. Also, if text on the RegistrationHeading label is equal to Registration, LoginDP will be set to State2. We will define these actions by creating two cases: UpdateVariables and ShowLogInState. Updating Variables and hiding the RegistrationLightBoxDP In the Widget Manger pane, double-click on the RegistrationLightBoxDP State1 to open in the design area. To define the UpdateVariables case for the OnClick interaction, click on the SubmitButton at coordinates (25,190). In the Widget Interactions and Notes pane with the Interactions tab selected, click on Add Case…. A Case Editor dialog box will open. In the Case Name field, type UpdateVariables. In the Case Editor dialog, perform the following steps: The following screenshot shows Case Editor with the actions defined: Create the first action; to set variable value for the Email and Password variables, perform the following steps: Under Click to add actions, scroll to the Widgets drop-down menu and click on Set Variable Value. Under Configure actions, click on the checkbox next to Email. Under Set variable to, click on the first dropdown and select text on widget. Click on the second dropdown and select EnterEmailField. Under Configure actions, click on the checkbox next to Password. Under Set variable to, click on the first dropdown and select text on widget. Click on the second dropdown and select EnterPasswordField. Create the second action; to hide RegistrationLightBoxDP, perform the following steps: Under Click to add actions, scroll to the Widgets dropdown, click on the Show/Hide dropdown and click on Hide. Under Configure actions, click on the checkbox next to RegistrationLightBoxDP. Click on OK. With the UpdateVariables case completed, next we will create the ShowLogInState case. Creating the ShowLoginState case To create the ShowLogInState case, in the Widget Interactions and Notes pane with the Interactions tab selected click on Add Case…. A Case Editor dialog box will open. In the Case Name field, type ShowLogInState. In the Case Editor dialog, perform the following steps: Click on the Add Condition button to create the first condition. In the Condition Builder dialog box, go to the outlined condition box and perform the following steps: In the first dropdown, select text on widget. In the second dropdown, select RegistrationHeadline. In the third dropdown, select equals. In the fourth dropdown, select value. In the fifth dropdown, select Registration. Click on OK. Create the first action; to set text for the WelcomeLabel, perform the following steps: Under Click to add actions, scroll to the Widgets drop-down menu and click on Set Text. Under Configure actions, click on the checkbox next to WelcomeLabel. Under Set text to, click on the dropdown and select value. In the text field, enter Welcome, [[Email]]. Click on OK. Create the second action; to set panel state for the LogInDP dynamic panel, perform the following steps: Under Click to add actions, scroll to the Dynamic Panels drop-down menu and click on Set Panel State. Under Configure actions, click on the checkbox next to LoginDP. Next to Select the state, click on the dropdown and select State2. Create the third action; to set value of the LoggedIn variable, perform the following steps: Under Click to add actions, scroll to the Variables drop-down menu and click on Set Variable Value. Under Configure actions, click on the checkbox next to LoggedIn. Under Set variable to, click on the first dropdown and click on value. In the text field, enter [[Email]]. Click on OK. Under the OnClick event, right-click on the ShowErrorMessage case and click on Toggle IF/ELSE IF. With our Header master updated, we are now ready to refresh data for our Forum repeater. Summary We learned how to leverage masters and pages from our community site to create a new blog site. We enhanced the Header master and refined the interactions for our Header master. Resources for Article: Further resources on this subject: Home Page Structure [article] Axure RP 6 Prototyping Essentials: Advanced Interactions [article] Common design patterns and how to prototype them [article]
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Packt
10 Aug 2015
8 min read
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Hands-on with Prezi Mechanics

Packt
10 Aug 2015
8 min read
In this In this article by J.J. Sylvia IV, author of the book Mastering Prezi for Business Presentations - Second Edition, we will see how to edit a figure and to style symbols. Also we will see the Grouping feature and brief introduction of the Prezi text editor. (For more resources related to this topic, see here.) Editing lines When editing lines or arrows, you can change them from being straight to curved by dragging the center point in any direction: This is extremely useful when creating the line drawings we saw earlier. It's also useful to get arrows pointing at various objects on your canvas: Styled symbols If you're on a tight deadline, or trying to create drawings with shapes simply isn't for you, then the styles available in Prezi may be of more interest to you. These are common symbols that Prezi has created in a few different styles that can be easily inserted into any of your presentations. You can select these from the same Symbols & shapes… option from the Insert menu where we found the symbols. You'll see several different styles to choose from on the right-hand side of your screen. Each of these categories has similar symbols, but styled differently. There is a wide variety of symbols available ranging from people to social media logos. You can pick a style that best matches your theme or the atmosphere you've created for your presentation. Instead of creating your own person from shapes, you can select from a variety of people symbols available: Although these symbols can be very handy, you should be aware that you can't edit them as part of your presentation. If you decide to use one, note that it will work as it is—there are no new hairstyles for these symbols. Highlighter The highlighter tool is extremely useful for pointing out key pieces of information such as an interesting fact. To use it, navigate to the Insert menu and select the Highlighter option. Then, just drag the cursor across the text you'd like to highlight. Once you've done this, the highlighter marks become objects in their own right, so you can click on them to change their size or position just as you would do for a shape. To change the color of your highlighter, you will need to go into the Theme Wizard and edit the RGB values. We'll cover how to do this later when we discuss branding. Grouping Grouping is a great feature that allows you to move or edit several different elements of your presentation at once. This can be especially useful if you're trying to reorganize the layout of your Prezi after it's been created, or to add animations to several elements at once. Let's go back to the drawing we created earlier to see how this might work: The first way to group items is to hold down the Ctrl key (Command on Mac OS) and to left-click on each element you want to group individually. In this case, I need to click on each individual line that makes up the flat top hair in the preceding image. This might be necessary if I only want to group the hair, for example: Another method for grouping is to hold down the Shift key while dragging your mouse to select multiple items at once. In the preceding screenshot, I've selected my entire person at once. Now, I can easily rotate, resize, or move the entire person at once, without having to move each individual line or shape. If you select a group of objects, move them, and then realize that a piece is missing because it didn't get selected, just press the Ctrl+Z (Command+Z on Mac OS) keys on your keyboard to undo the move. Then, broaden your selection and try again. Alternatively, you can hold down the Shift key and simply click on the piece you missed to add it to the group. If we want to keep these elements grouped together instead of having to reselect them each time we decide to make a change, we can click on the Group button that appears with this change. Now these items will stay grouped unless we click on the new Ungroup button, now located in the same place as the Group button previously was: You can also use frames to group material together. If you already created frames as part of your layout, this might make the grouping process even easier. Prezi text editor Over the years, the Prezi text editor has evolved to be quite robust, and it's now possible to easily do all of your text editing directly within Prezi. Spell checker When you spell something incorrectly, Prezi will underline the word it doesn't recognize with a red line. This is just as you would see it in Microsoft Word or any other text editor. To correct the word, simply right-click on it (or Command + Click on Mac OS) and select the word you meant to type from the suggestions, as shown in the following screenshot: The text drag-apart feature So a colleague of yours has just e-mailed you the text that they want to appear in the Prezi you're designing for them? That's great news as it'll help you understand the flow of the presentation. What's frustrating, though, is that you'll have to copy and paste every single line or paragraph across to put it in the right place on your canvas. At least, that used to be the case before Prezi introduced the drag-apart feature in the text editor. This means you can now easily drag a selection of text anywhere on your canvas without having to rely on the copy and paste options. Let's see how we can easily change the text we spellchecked previously, as shown in the following screenshot: In order to drag your text apart, simply highlight the area you require, hold the mouse button down, and then drag the text anywhere on your canvas. Once you have separated your text, you can then edit the separate parts as you would edit any other individual object on your canvas. In this example, we can change the size of the company name and leave the other text as it is, which we couldn't do within a single textbox: Building Prezis for colleagues If you've kindly offered to build a Prezi for one of your colleagues, ask them to supply the text for it in Word format. You'll be able to run a spellcheck on it from there before you copy and paste it into Prezi. Any bad spellings you miss will also get highlighted on your Prezi canvas but it's good to use both options as a safety net. Font colors Other than dragging text apart to make it stand out more on its own, you might want to highlight certain words so that they jump out at your audience even more. The great news is that you can now highlight individual lines of text or single words and change their color. To do so, just highlight a word by clicking and dragging your mouse across it. Then, click on the color picker at the top of the textbox to see the color menu, as shown in the following screenshot: Select any of the colors available in the palette to change the color of that piece of text. Nothing else in the textbox will be affected apart from the text you have selected. This gives you much greater freedom to use colored text in your Prezi design, and doesn't leave you restricted as in older versions of the software. Choose the right color To make good use of this feature, we recommend that you use a color that completely contrasts to the rest of your design. For example, if your design and corporate colors are blue, we suggest you use red or purple to highlight key words. Also, once you pick a color, stick to it throughout the presentation so that your audience knows when they see a key piece of information. Bullet points and indents Bullets and indents make it much easier to put together your business presentations and helps to give the audience some short, simple information as text in the same format they're used to seeing in other presentations. This can be done by simply selecting the main body of text and clicking on the bullet point icon at the top of the textbox. This is a really simple feature, but a useful one nonetheless. We'd obviously like to point out that too much text on any presentation is a bad thing. Keep it short and to the point. Also, remember that too many bullets can kill a presentation. Summary In this article, we discussed the basic mechanics of Prezi. Learning to combine these tools in creative ways will help you move from a Prezi novice to master. Shapes can be used creatively to create content and drawings, and can be grouped together for easy movement and editing. Prezi also features basic text editing which are explained in this article. Resources for Article: Further resources on this subject: Turning your PowerPoint into a Prezi [Article] The Fastest Way to Go from an Idea to a Prezi [Article] Using Prezi - The Online Presentation Software Tool [Article]
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10 Aug 2015
10 min read
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Securing OpenStack Networking

Packt
10 Aug 2015
10 min read
In this article by Fabio Alessandro Locati, author of the book OpenStack Cloud Security, you will learn about the importance of firewall, IDS, and IPS. You will also learn about Generic Routing Encapsulation, VXLAN. (For more resources related to this topic, see here.) The importance of firewall, IDS, and IPS The security of a network can and should be achieved in multiple ways. Three components that are critical to the security of a network are: Firewall Intrusion detection system (IDS) Intrusion prevention system (IPS) Firewall Firewalls are systems that control traffic passing through them based on rules. This can seem something like a router, but they are very different. The router allows communication between different networks while the firewall limits communication between networks and hosts. The root of this confusion may occur because very often the router will have the firewall functionality and vice versa. Firewalls need to be connected in a series to your infrastructure. The first paper on the firewall technology appeared in 1988 and designed the packet filter firewall. This kind of firewall is often known as first generation firewall. This kind of firewall analyzes the packages passing through and if the package matches a rule, the firewall will act accordingly to that rule. This firewall will analyze each package by itself and will not consider other aspects such as other packages. It works on the first three layers of the OSI model with very few features using layer 4 specifically to check port numbers and protocols (UDP/TCP). First generation firewalls are still in use, because in a lot of situations, to do the job properly and are cheap and secure. Examples of typical filtering those firewalls prohibit (or allow) to IPs of certain classes (or specific IPs), to access certain IPs, or allow traffic to a specific IP only on specific ports. There are no known attacks to those kind of firewalls, but specific models can have specific bugs that can be exploited. In 1990, a new generation of firewall appeared. The initial name was circuit-level gateway, but today it is far more commonly known as stateful firewalls or second generation firewall. These firewalls are able to understand when connections are being initialized and closed so that the firewall comes to know what is the current state of a connection when a package arrives. To do so, this kind of firewall uses the first four layers of the networking stack. This allows the firewall to drop all packages that are not establishing a new connection or are in an already established connection. These firewalls are very powerful with the TCP protocol because it has states, while they have very small advantages compared to first generation firewalls handling UDP or ICMP packages, since those packages travel with no connection. In these cases, the firewall sets the connection as established; only the first valid package passes through and closes it after the connection times out. Performance-wise, stateful firewall can be faster than packet firewall because if the package is part of an active connection, no further test will be performed against that package. These kinds of firewalls are more susceptible to bugs in their code since reading more about the package makes it easier to exploit. Also, on many devices, it is possible to open connections (with SYN packages) until the firewall is saturated. In such cases, the firewall usually downgrades itself as a simple router allowing all traffic to pass through it. In 1991, improvements were made to the stateful firewall allowing it to understand more about the protocol of the package it was evaluating. The firewalls of this kind before 1994 had major problems, such as working as a proxy that the user had to interact with. In 1994, the first application firewall, as we know it, was born doing all its job completely transparently. To be able to understand the protocol, this kind of firewall requires an understanding of all seven layers of the OSI model. As for security, the same as the stateful firewall does apply to the application firewall as well. Intrusion detection system (IDS) IDSs are systems that monitor the network traffic looking for policy violation and malicious traffic. The goal of the IDS is not to block malicious activity, but instead to log and report them. These systems act in a passive mode, so you'll not see any traffic coming from them. This is very important because it makes them invisible to attackers so you can gain information about the attack, without the attacker knowing. IDSs need to be connected in parallel to your infrastructure. Intrusion prevention system (IPS) IPSs are sometimes referred to as Intrusion Detection and Prevention Systems (IDPS), since they are IDS that are also able to fight back malicious activities. IPSs have greater possibility to act than IDSs. Other than reporting, like IDS, they can also drop malicious packages, reset the connection, and block the traffic from the offending IP address. IPSs need to be connected in series to your infrastructure. Generic Routing Encapsulation (GRE) GRE is a Cisco tuning protocol that is difficult to position in the OSI model. The best place for it to be is between layers 2 and 3. Being above layer 2 (where VLANs are), we can use GRE inside VLAN. We will not go deep into the technicalities of this protocol. I'd like to focus more on the advantages and disadvantages it has over VLAN. The first advantage of (extended) GRE over VLAN is scalability. In fact, VLAN is limited to 4,096, while GRE tunnels do not have this limitation. If you are running a private cloud and you are working in a small corporation, 4,096 networks could be enough, but will definitely not be enough if you work for a big corporation or if you are running a public cloud. Also, unless you use VTP for your VLANs, you'll have to add VLANs to each network device, while GREs don't need this. You cannot have more than 4,096 VLANs in an environment. The second advantage is security. Since you can deploy multiple GRE tunnels in a single VLAN, you can connect a machine to a single VLAN and multiple GRE networks without the risks that come with putting a port in trunking that is needed to bring more VLANs in the same physical port. For these reasons, GRE has been a very common choice in a lot of OpenStack clusters deployed up to OpenStack Havana. The current preferred networking choice (since Icehouse) is Virtual Extensible LAN (VXLAN). VXLAN VXLAN is a network virtualization technology whose specifications have been originally created by Arista Networks, Cisco, and VMWare, and many other companies have backed the project. Its goal is to offer a standardized overlay encapsulation protocol and it was created because the standard VLAN were too limited for the current cloud needs and the GRE protocol was a Cisco protocol. It works using layer 2 Ethernet frames within layer 4 UDP packages on port 4789. As for the maximum number of networks, the limit is 16 million logical networks. Since the Icehouse release, the suggested standard for networking is VXLAN. Flat network versus VLAN versus GRE in OpenStack Quantum In OpenStack Quantum, you can decide to use multiple technologies for your networks: flat network, VLAN, GRE, and the most recent, VXLAN. Let's discuss them in detail: Flat network: It is often used in private clouds since it is very easy to set up. The downside is that any virtual machine will see any other virtual machines in our cloud. I strongly discourage people from using this network design because it's unsafe, and in the long run, it will have problems, as we have seen earlier. VLAN: It is sometimes used in bigger private clouds and sometimes even in small public clouds. The advantage is that many times you already have a VLAN-based installation in your company. The major disadvantages are the need to trunk ports for each physical host and the possible problems in propagation. I discourage this approach, since in my opinion, the advantages are very limited while the disadvantages are pretty strong. VXLAN: It should be used in any kind of cloud due to its technical advantages. It allows a huge number of networks, its way more secure, and often eases debugging. GRE: Until the Havana release, it was the suggested protocol, but since the Icehouse release, the suggestion has been to move toward VXLAN, where the majority of the development is focused. Design a secure network for your OpenStack deployment As for the physical infrastructure, we have to design it securely. We have seen that the network security is critical and that there a lot of possible attacks in this realm. Is it possible to design a secure environment to run OpenStack? Yes it is, if you remember a few rules: Create different networks, at the very least for management and external data (this network usually already exists in your organization and is the one where all your clients are) Never put ports on trunking mode if you use VLANs in your infrastructure, otherwise physically separated networks will be needed The following diagram is an example of how to implement it: Here, the management, tenant external networks could be either VLAN or real networks. Remember that to not use VLAN trunking, you need at least the same amount of physical ports as of VLAN, and the machine has to be subscribed to avoid port trunking that can be a huge security hole. A management network is needed for the administrator to administer the machines and for the OpenStack services to speak to each other. This network is critical, since it may contain sensible data, and for this reason, it has to be disconnected from other networks, or if not possible, have very limited connectivity. The external network is used by virtual machines to access the Internet (and vice versa). In this network, all machines will need an IP address reachable from the Web. The tenant network, sometimes even called internal or guest network is the network where the virtual machines can communicate with other virtual machines in the same cloud. This network, in some deployment cases, can be merged with the external network, but this choice has some security drawbacks. The API network is used to expose OpenStack APIs to the users. This network requires IP addresses reachable from the Web, and for this reason, is often merged into the external network. There are cases where provider networks are needed to connect tenant networks to existing networks outside the OpenStack cluster. Those networks are created by the OpenStack administrator and map directly to an existing physical network in the data center. Summary In this article, we have seen how networking works, which attacks we can expect, and how we can counter them. Also, we have seen how to implement a secure deployment of OpenStack Networking. Resources for Article: Further resources on this subject: Cloud distribution points [Article] Photo Stream with iCloud [Article] Integrating Accumulo into Various Cloud Platforms [Article]
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Packt
10 Aug 2015
7 min read
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Exploring Jenkins

Packt
10 Aug 2015
7 min read
In this article by Mitesh Soni, the author of the book Jenkins Essentials, introduces us to Jenkins. (For more resources related to this topic, see here.) Jenkins is an open source application written in Java. It is one of the most popular continuous integration (CI) tools used to build and test different kinds of projects. In this article, we will have a quick overview of Jenkins, essential features, and its impact on DevOps culture. Before we can start using Jenkins, we need to install it. In this article, we have provided a step-by-step guide to install Jenkins. Installing Jenkins is a very easy task and is different from the OS flavors. This article will also cover the DevOps pipeline. To be precise, we will discuss the following topics in this article: Introduction to Jenkins and its features Installation of Jenkins on Windows and the CentOS operating system How to change configuration settings in Jenkins What is the deployment pipeline On your mark, get set, go! Introduction to Jenkins and its features Let's first understand what continuous integration is. CI is one of the most popular application development practices in recent times. Developers integrate bug fix, new feature development, or innovative functionality in code repository. The CI tool verifies the integration process with an automated build and automated test execution to detect issues with the current source of an application, and provide quick feedback. Jenkins is a simple, extensible, and user-friendly open source tool that provides CI services for application development. Jenkins supports SCM tools such as StarTeam, Subversion, CVS, Git, AccuRev and so on. Jenkins can build Freestyle, Apache Ant, and Apache Maven-based projects. The concept of plugins makes Jenkins more attractive, easy to learn, and easy to use. There are various categories of plugins available such as Source code management, Slave launchers and controllers, Build triggers, Build tools, Build notifies, Build reports, other post-build actions, External site/tool integrations, UI plugins, Authentication and user management, Android development, iOS development, .NET development, Ruby development, Library plugins, and so on. Jenkins defines interfaces or abstract classes that model a facet of a build system. Interfaces or abstract classes define an agreement on what needs to be implemented; Jenkins uses plugins to extend those implementations. To learn more about all plugins, visit https://wiki.jenkins-ci.org/x/GIAL. To learn how to create a new plugin, visit https://wiki.jenkins-ci.org/x/TYAL. To download different versions of plugins, visit https://updates.jenkins-ci.org/download/plugins/. Features Jenkins is one of the most popular CI servers in the market. The reasons for its popularity are as follows: Easy installation on different operating systems. Easy upgrades—Jenkins has very speedy release cycles. Simple and easy-to-use user interface. Easily extensible with the use of third-party plugins—over 400 plugins. Easy to configure the setup environment in the user interface. It is also possible to customize the user interface based on likings. The master slave architecture supports distributed builds to reduce loads on the CI server. Jenkins is available with test harness built around JUnit; test results are available in graphical and tabular forms. Build scheduling based on the cron expression (to know more about cron, visit http://en.wikipedia.org/wiki/Cron). Shell and Windows command execution in prebuild steps. Notification support related to the build status. Installation of Jenkins on Windows and CentOS Go to https://jenkins-ci.org/. Find the Download Jenkins section on the home page of Jenkins's website. Download the war file or native packages based on your operating system. A Java installation is needed to run Jenkins. Install Java based on your operating system and set the JAVA_HOME environment variable accordingly. Installing Jenkins on Windows Select the native package available for Windows. It will download jenkins-1.xxx.zip. In our case, it will download jenkins-1.606.zip. Extract it and you will get setup.exe and jenkins-1.606.msi files. Click on setup.exe and perform the following steps in sequence. On the welcome screen, click Next: Select the destination folder and click on Next. Click on Install to begin installation. Please wait while the Setup Wizard installs Jenkins. Once the Jenkins installation is completed, click on the Finish button. Verify the Jenkins installation on the Windows machine by opening URL http://<ip_address>:8080 on the system where you have installed Jenkins. Installation of Jenkins on CentOS To install Jenkins on CentOS, download the Jenkins repository definition to your local system at /etc/yum.repos.d/ and import the key. Use the wget -O /etc/yum.repos.d/jenkins.repo http://pkg.jenkins-ci.org/redhat/jenkins.repo command to download repo. Now, run yum install Jenkins; it will resolve dependencies and prompt for installation. Reply with y and it will download the required package to install Jenkins on CentOS. Verify the Jenkins status by issuing the service jenkins status command. Initially, it will be stopped. Start Jenkins by executing service jenkins start in the terminal. Verify the Jenkins installation on the CentOS machine by opening the URL http://<ip_address>:8080 on the system where you have installed Jenkins. How to change configuration settings in Jenkins Click on the Manage Jenkins link on the dashboard to configure system, security, to manage plugins, slave nodes, credentials, and so on. Click on the Configure System link to configure Java, Ant, Maven, and other third-party products' related information. Jenkins uses Groovy as its scripting language. To execute the arbitrary script for administration/trouble-shooting/diagnostics on the Jenkins dashboard, go to the Manage Jenkins link on the dashboard, click on Script Console, and run println(Jenkins.instance.pluginManager.plugins). To verify the system log, go to the Manage Jenkins link on the dashboard and click on the System Log link or visit http://localhost:8080/log/all. To get more information on third-party libraries—version and license information in Jenkins, go to the Manage Jenkins link on the dashboard and click on the About Jenkins link. What is the deployment pipeline? The application development life cycle is a traditionally lengthy and a manual process. In addition, it requires effective collaboration between development and operations teams. The deployment pipeline is a demonstration of automation involved in the application development life cycle containing the automated build execution and test execution, notification to the stakeholder, and deployment in different runtime environments. Effectively, the deployment pipeline is a combination of CI and continuous delivery, and hence is a part of DevOps practices. The following diagram depicts the deployment pipeline process: Members of the development team check code into a source code repository. CI products such as Jenkins are configured to poll changes from the code repository. Changes in the repository are downloaded to the local workspace and Jenkins triggers an automated build process, which is assisted by Ant or Maven. Automated test execution or unit testing, static code analysis, reporting, and notification of successful or failed build process are also part of the CI process. Once the build is successful, it can be deployed to different runtime environments such as testing, preproduction, production, and so on. Deploying a war file in terms of the JEE application is normally the final stage in the deployment pipeline. One of the biggest benefits of the deployment pipeline is the faster feedback cycle. Identification of issues in the application at early stages and no dependencies on manual efforts make this entire end-to-end process more effective. To read more, visit http://martinfowler.com/bliki/DeploymentPipeline.html and http://www.informit.com/articles/article.aspx?p=1621865&seqNum=2. Summary Congratulations! We reached the end of this article and hence we have Jenkins installed on our physical or virtual machine. Till now, we covered the basics of CI and the introduction to Jenkins and its features. We completed the installation of Jenkins on Windows and CentOS platforms. In addition to this, we discussed the deployment pipeline and its importance in CI. Resources for Article: Further resources on this subject: Jenkins Continuous Integration [article] Running Cucumber [article] Introduction to TeamCity [article]
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Packt
10 Aug 2015
17 min read
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The Splunk Interface

Packt
10 Aug 2015
17 min read
In this article by Vincent Bumgarner & James D. Miller, author of the book, Implementing Splunk - Second Edition, we will walk through the most common elements in the Splunk interface, and will touch upon concepts that will be covered in greater detail. You may want to dive right into the search section, but an overview of the user interface elements might save you some frustration later. We will cover the following topics: Logging in and app selection A detailed explanation of the search interface widgets A quick overview of the admin interface (For more resources related to this topic, see here.) Logging into Splunk The Splunk GUI interface (Splunk is also accessible through its command-line interface [CLI] and REST API) is web-based, which means that no client needs to be installed. Newer browsers with fast JavaScript engines, such as Chrome, Firefox, and Safari, work better with the interface. As of Splunk Version 6.2.0, no browser extensions are required. Splunk Versions 4.2 and earlier require Flash to render graphs. Flash can still be used by older browsers, or for older apps that reference Flash explicitly. The default port for a Splunk installation is 8000. The address will look like: http://mysplunkserver:8000 or http://mysplunkserver.mycompany.com:8000. The Splunk interface If you have installed Splunk on your local machine, the address can be some variant of http://localhost:8000, http://127.0.0.1:8000, http://machinename:8000, or http://machinename.local:8000. Once you determine the address, the first page you will see is the login screen. The default username is admin with the password changeme. The first time you log in, you will be prompted to change the password for the admin user. It is a good idea to change this password to prevent unwanted changes to your deployment. By default, accounts are configured and stored within Splunk. Authentication can be configured to use another system, for instance Lightweight Directory Access Protocol (LDAP). By default, Splunk authenticates locally. If LDAP is set up, the order is as follows: LDAP / Local. The home app After logging in, the default app is the Launcher app (some may refer to this as Home). This app is a launching pad for apps and tutorials. In earlier versions of Splunk, the Welcome tab provided two important shortcuts, Add data and the Launch search app. In version 6.2.0, the Home app is divided into distinct areas, or panes, that provide easy access to Explore Splunk Enterprise (Add Data, Splunk Apps, Splunk Docs, and Splunk Answers) as well as Apps (the App management page) Search & Reporting (the link to the Search app), and an area where you can set your default dashboard (choose a home dashboard).                 The Explore Splunk Enterprise pane shows links to: Add data: This links Add Data to the Splunk page. This interface is a great start for getting local data flowing into Splunk (making it available to Splunk users). The Preview data interface takes an enormous amount of complexity out of configuring dates and line breaking. Splunk Apps: This allows you to find and install more apps from the Splunk Apps Marketplace (http://apps.splunk.com). This marketplace is a useful resource where Splunk users and employees post Splunk apps, mostly free but some premium ones as well. Splunk Answers: This is one of your links to the wide amount of Splunk documentation available, specifically http://answers.splunk.com, where you can engage with the Splunk community on Splunkbase (https://splunkbase.splunk.com/) and learn how to get the most out of your Splunk deployment. The Apps section shows the apps that have GUI elements on your instance of Splunk. App is an overloaded term in Splunk. An app doesn't necessarily have a GUI at all; it is simply a collection of configurations wrapped into a directory structure that means something to Splunk. Search & Reporting is the link to the Splunk Search & Reporting app. Beneath the Search & Reporting link, Splunk provides an outline which, when you hover over it, displays a Find More Apps balloon tip. Clicking on the link opens the same Browse more apps page as the Splunk Apps link mentioned earlier. Choose a home dashboard provides an intuitive way to select an existing (simple XML) dashboard and set it as part of your Splunk Welcome or Home page. This sets you at a familiar starting point each time you enter Splunk. The following image displays the Choose Default Dashboard dialog: Once you select an existing dashboard from the dropdown list, it will be part of your welcome screen every time you log into Splunk – until you change it. There are no dashboards installed by default after installing Splunk, except the Search & Reporting app. Once you have created additional dashboards, they can be selected as the default. The top bar The bar across the top of the window contains information about where you are, as well as quick links to preferences, other apps, and administration. The current app is specified in the upper-left corner. The following image shows the upper-left Splunk bar when using the Search & Reporting app: Clicking on the text takes you to the default page for that app. In most apps, the text next to the logo is simply changed, but the whole block can be customized with logos and alternate text by modifying the app's CSS. The upper-right corner of the window, as seen in the previous image, contains action links that are almost always available: The name of the user who is currently logged in appears first. In this case, the user is Administrator. Clicking on the username allows you to select Edit Account (which will take you to the Your account page) or to Logout (of Splunk). Logout ends the session and forces the user to login again. The following screenshot shows what the Your account page looks like: This form presents the global preferences that a user is allowed to change. Other settings that affect users are configured through permissions on objects and settings on roles. (Note: preferences can also be configured using the CLI or by modifying specific Splunk configuration files). Full name and Email address are stored for the administrator's convenience. Time zone can be changed for the logged-in user. This is a new feature in Splunk 4.3. Setting the time zone only affects the time zone used to display the data. It is very important that the date is parsed properly when events are indexed. Default app controls the starting page after login. Most users will want to change this to search. Restart backgrounded jobs controls whether unfinished queries should run again if Splunk is restarted. Set password allows you to change your password. This is only relevant if Splunk is configured to use internal authentication. For instance, if the system is configured to use Windows Active Directory via LDAP (a very common configuration), users must change their password in Windows. Messages allows you to view any system-level error messages you may have pending. When there is a new message for you to review, a notification displays as a count next to the Messages menu. You can click the X to remove a message. The Settings link presents the user with the configuration pages for all Splunk Knowledge objects, Distributed Environment settings, System and Licensing, Data, and Users and Authentication settings. If you do not see some of these options, you do not have the permissions to view or edit them. The Activity menu lists shortcuts to Splunk Jobs, Triggered Alerts, and System Activity views. You can click Jobs (to open the search jobs manager window, where you can view and manage currently running searches), click Triggered Alerts (to view scheduled alerts that are triggered) or click System Activity (to see dashboards about user activity and the status of the system). Help lists links to video Tutorials, Splunk Answers, the Splunk Contact Support portal, and online Documentation. Find can be used to search for objects within your Splunk Enterprise instance. For example, if you type in error, it returns the saved objects that contain the term error. These saved objects include Reports, Dashboards, Alerts, and so on. You can also search for error in the Search & Reporting app by clicking Open error in search. The search & reporting app The Search & Reporting app (or just the search app) is where most actions in Splunk start. This app is a dashboard where you will begin your searching. The summary view Within the Search & Reporting app, the user is presented with the Summary view, which contains information about the data which that user searches for by default. This is an important distinction—in a mature Splunk installation, not all users will always search all data by default. But at first, if this is your first trip into Search & Reporting, you'll see the following: From the screen depicted in the previous screenshot, you can access the Splunk documentation related to What to Search and How to Search. Once you have at least some data indexed, Splunk will provide some statistics on the available data under What to Search (remember that this reflects only the indexes that this particular user searches by default; there are other events that are indexed by Splunk, including events that Splunk indexes about itself.) This is seen in the following image: In previous versions of Splunk, panels such as the All indexed data panel provided statistics for a user's indexed data. Other panels gave a breakdown of data using three important pieces of metadata—Source, Sourcetype, and Hosts. In the current version—6.2.0—you access this information by clicking on the button labeled Data Summary, which presents the following to the user: This dialog splits the information into three tabs—Hosts, Sources and Sourcetypes. A host is a captured hostname for an event. In the majority of cases, the host field is set to the name of the machine where the data originated. There are cases where this is not known, so the host can also be configured arbitrarily. A source in Splunk is a unique path or name. In a large installation, there may be thousands of machines submitting data, but all data on the same path across these machines counts as one source. When the data source is not a file, the value of the source can be arbitrary, for instance, the name of a script or network port. A source type is an arbitrary categorization of events. There may be many sources across many hosts, in the same source type. For instance, given the sources /var/log/access.2012-03-01.log and /var/log/access.2012-03-02.log on the hosts fred and wilma, you could reference all these logs with source type access or any other name that you like. Let's move on now and discuss each of the Splunk widgets (just below the app name). The first widget is the navigation bar. As a general rule, within Splunk, items with downward triangles are menus. Items without a downward triangle are links. Next we find the Search bar. This is where the magic starts. We'll go into great detail shortly. Search Okay, we've finally made it to search. This is where the real power of Splunk lies. For our first search, we will search for the word (not case specific); error. Click in the search bar, type the word error, and then either press Enter or click on the magnifying glass to the right of the bar. Upon initiating the search, we are taken to the search results page. Note that the search we just executed was across All time (by default); to change the search time, you can utilize the Splunk time picker. Actions Let's inspect the elements on this page. Below the Search bar, we have the event count, action icons, and menus. Starting from the left, we have the following: The number of events matched by the base search. Technically, this may not be the number of results pulled from disk, depending on your search. Also, if your query uses commands, this number may not match what is shown in the event listing. Job: This opens the Search job inspector window, which provides very detailed information about the query that was run. Pause: This causes the current search to stop locating events but keeps the job open. This is useful if you want to inspect the current results to determine whether you want to continue a long running search. Stop: This stops the execution of the current search but keeps the results generated so far. This is useful when you have found enough and want to inspect or share the results found so far. Share: This shares the search job. This option extends the job's lifetime to seven days and sets the read permissions to everyone. Export: This exports the results. Select this option to output to CSV, raw events, XML, or JavaScript Object Notation (JSON) and specify the number of results to export. Print: This formats the page for printing and instructs the browser to print. Smart Mode: This controls the search experience. You can set it to speed up searches by cutting down on the event data it returns and, additionally, by reducing the number of fields that Splunk will extract by default from the data (Fast mode). You can, otherwise, set it to return as much event information as possible (Verbose mode). In Smart mode (the default setting) it toggles search behavior based on the type of search you're running. Timeline Now we'll skip to the timeline below the action icons. Along with providing a quick overview of the event distribution over a period of time, the timeline is also a very useful tool for selecting sections of time. Placing the pointer over the timeline displays a pop-up for the number of events in that slice of time. Clicking on the timeline selects the events for a particular slice of time. Clicking and dragging selects a range of time. Once you have selected a period of time, clicking on Zoom to selection changes the time frame and reruns the search for that specific slice of time. Repeating this process is an effective way to drill down to specific events. Deselect shows all events for the time range selected in the time picker. Zoom out changes the window of time to a larger period around the events in the current time frame The field picker To the left of the search results, we find the field picker. This is a great tool for discovering patterns and filtering search results. Fields The field list contains two lists: Selected Fields, which have their values displayed under the search event in the search results Interesting Fields, which are other fields that Splunk has picked out for you Above the field list are two links: Hide Fields and All Fields. Hide Fields: Hides the field list area from view. All Fields: Takes you to the Selected Fields window. Search results We are almost through with all the widgets on the page. We still have a number of items to cover in the search results section though, just to be thorough. As you can see in the previous screenshot, at the top of this section, we have the number of events displayed. When viewing all results in their raw form, this number will match the number above the timeline. This value can be changed either by making a selection on the timeline or by using other search commands. Next, we have the action icons (described earlier) that affect these particular results. Under the action icons, we have four results tabs: Events list, which will show the raw events. This is the default view when running a simple search, as we have done so far. Patterns streamlines the event pattern detection. It displays a list of the most common patterns among the set of events returned by your search. Each of these patterns represents the number of events that share a similar structure. Statistics populates when you run a search with transforming commands such as stats, top, chart, and so on. The previous keyword search for error does not display any results in this tab because it does not have any transforming commands. Visualization transforms searches and also populates the Visualization tab. The results area of the Visualization tab includes a chart and the statistics table used to generate the chart. Not all searches are eligible for visualization. Under the tabs described just now, is the timeline. Options Beneath the timeline, (starting at the left) is a row of option links that include: Show Fields: shows the Selected Fields screen List: allows you to select an output option (Raw, List, or Table) for displaying the search results Format: provides the ability to set Result display options, such as Show row numbers, Wrap results, the Max lines (to display) and Drilldown as on or off. NN Per Page: is where you can indicate the number of results to show per page (10, 20, or 50). To the right are options that you can use to choose a page of results, and to change the number of events per page. In prior versions of Splunk, these options were available from the Results display options popup dialog. The events viewer Finally, we make it to the actual events. Let's examine a single event. Starting at the left, we have: Event Details: Clicking here (indicated by the right facing arrow) opens the selected event, providing specific information about the event by type, field, and value, and allows you the ability to perform specific actions on a particular event field. In addition, Splunk version 6.2.0 offers a button labeled Event Actions to access workflow actions, a few of which are always available. Build Eventtype: Event types are a way to name events that match a certain query. Extract Fields: This launches an interface for creating custom field extractions. Show Source: This pops up a window with a simulated view of the original source. The event number: Raw search results are always returned in the order most recent first. Next to appear are any workflow actions that have been configured. Workflow actions let you create new searches or links to other sites, using data from an event. Next comes the parsed date from this event, displayed in the time zone selected by the user. This is an important and often confusing distinction. In most installations, everything is in one time zone—the servers, the user, and the events. When one of these three things is not in the same time zone as the others, things can get confusing. Next, we see the raw event itself. This is what Splunk saw as an event. With no help, Splunk can do a good job finding the date and breaking lines appropriately, but as we will see later, with a little help, event parsing can be more reliable and more efficient. Below the event are the fields that were selected in the field picker. Clicking on the value adds the field value to the search. Summary As you have seen, the Splunk GUI provides a rich interface for working with search results. We have really only scratched the surface and will cover more elements. Resources for Article: Further resources on this subject: The Splunk Web Framework [Article] Loading data, creating an app, and adding dashboards and reports in Splunk [Article] Working with Apps in Splunk [Article]
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article-image-introduction-wep
Packt
10 Aug 2015
4 min read
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An Introduction to WEP

Packt
10 Aug 2015
4 min read
In this article by Marco Alamanni, author of the book, Kali Linux Wireless Penetration Testing Essentials, has explained that the WEP protocol was introduced with the original 802.11 standard as a means to provide authentication and encryption to wireless LAN implementations. It is based on the RC4 (Rivest Cipher 4) stream cypher with a preshared secret key (PSK) of 40 or 104 bits, depending on the implementation. A 24 bit pseudo-random Initialization Vector (IV) is concatenated with the preshared key to generate the per-packet keystream used by RC4 for the actual encryption and decryption processes. Thus, the resulting keystream could be 64 or 128 bits long. (For more resources related to this topic, see here.) In the encryption phase, the keystream is XORed with the plaintext data to obtain the encrypted data, while in the decryption phase the encrypted data is XORed with the keystream to obtain the plaintext data. The encryption process is shown in the following diagram: Attacks against WEP First of all, we must say that WEP is an insecure protocol and has been deprecated by the Wi-Fi Alliance. It suffers from various vulnerabilities related to the generation of the keystreams, to the use of IVs and to the length of the keys. The IV is used to add randomness to the keystream, trying to avoid the reuse of the same keystream to encrypt different packets. This purpose has not been accomplished in the design of WEP, because the IV is only 24 bits long (with 2^24 = 16,777,216 possible values) and it is transmitted in clear-text within each frame. Thus, after a certain period of time (depending on the network traffic) the same IV, and consequently the same keystream, will be reused, allowing the attacker to collect the relative cypher texts and perform statistical attacks to recover the plain texts and the key. The first well-known attack against WEP was the Fluhrer, Mantin and Shamir (FMS) attack, back in 2001. The FMS attack relies on the way WEP generates the keystreams and on the fact that it also uses weak IVs to generate weak keystreams, making possible for an attacker to collect a sufficient number of packets encrypted with these keystreams, analyze them, and recover the key. The number of IVs to be collected to complete the FMS attack is about 250,000 for 40-bit keys and 1,500,000 for 104-bit keys. The FMS attack has been enhanced by Korek, improving its performances. Andreas Klein found more correlations between the RC4 keystream and the key than the ones discovered by Fluhrer, Mantin, and Shamir, that can used to crack the WEP key. In 2007, Pyshkin, Tews, and Weinmann (PTW) extended Andreas Klein's research and improved the FMS attack, significantly reducing the number of IVs needed to successfully recover the WEP key. Indeed, the PTW attack does not rely on weak IVs like the FMS attack does and is very fast and effective. It is able to recover a 104-bit WEP key with a success probability of 50 percent using less than 40,000 frames and with a probability of 95 percent with 85,000 frames. The PTW attack is the default method used by Aircrack-ng to crack WEP keys. Both the FMS and PTW attacks need to collect quite a large number of frames to succeed and can be conducted passively, sniffing the wireless traffic on the same channel of the target AP and capturing frames. The problem is that, in normal conditions, we will have to spend quite a long time to passively collect all the necessary packets for the attacks, especially with the FMS attack. To accelerate the process, the idea is to re-inject frames in the network to generate traffic in response so that we could collect the necessary IVs more quickly. A type of frame that is suitable for this purpose is the ARP request, because the AP broadcasts it and each time with a new IV. As we are not associated with the AP, if we send frames to it directly, they are discarded and a de-authentication frame is sent. Instead, we can capture ARP requests from associated clients and retransmit them to the AP. This technique is called the ARP Request Replay attack and is also adopted by Aircrack-ng for the implementation of the PTW attack. Summary In this article, we covered the WEP protocol, the attacks that have been developed to crack the keys. Resources for Article: Further resources on this subject: Kali Linux – Wireless Attacks [article] What is Kali Linux [article] Penetration Testing [article]
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Packt
10 Aug 2015
4 min read
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Sending and Syncing Data

Packt
10 Aug 2015
4 min read
This article, by Steven F. Daniel, author of the book, Android Wearable Programming, will provide you with the background and understanding of how you can effectively build applications that communicate between the Android handheld device and the Android wearable. Android Wear comes with a number of APIs that will help to make communicating between the handheld and the wearable a breeze. We will be learning the differences between using MessageAPI, which is sometimes referred to as a "fire and forget" type of message, and DataLayerAPI that supports syncing of data between a handheld and a wearable, and NodeAPI that handles events related to each of the local and connected device nodes. (For more resources related to this topic, see here.) Creating a wearable send and receive application In this section, we will take a look at how to create an Android wearable application that will send an image and a message, and display this on our wearable device. In the next sections, we will take a look at the steps required to send data to the Android wearable using DataAPI, NodeAPI, and MessageAPIs. Firstly, create a new project in Android Studio by following these simple steps: Launch Android Studio, and then click on the File | New Project menu option. Next, enter SendReceiveData for the Application name field. Then, provide the name for the Company Domain field. Now, choose Project location and select where you would like to save your application code: Click on the Next button to proceed to the next step. Next, we will need to specify the form factors for our phone/tablet and Android Wear devices using which our application will run. On this screen, we will need to choose the minimum SDK version for our phone/tablet and Android Wear. Click on the Phone and Tablet option and choose API 19: Android 4.4 (KitKat) for Minimum SDK. Click on the Wear option and choose API 21: Android 5.0 (Lollipop) for Minimum SDK: Click on the Next button to proceed to the next step. In our next step, we will need to add Blank Activity to our application project for the mobile section of our app. From the Add an activity to Mobile screen, choose the Add Blank Activity option from the list of activities shown and click on the Next button to proceed to the next step: Next, we need to customize the properties for Blank Activity so that it can be used by our application. Here we will need to specify the name of our activity, layout information, title, and menu resource file. From the Customize the Activity screen, enter MobileActivity for Activity Name shown and click on the Next button to proceed to the next step in the wizard: In the next step, we will need to add Blank Activity to our application project for the Android wearable section of our app. From the Add an activity to Wear screen, choose the Blank Wear Activity option from the list of activities shown and click on the Next button to proceed to the next step: Next, we need to customize the properties for Blank Wear Activity so that our Android wearable can use it. Here we will need to specify the name of our activity and the layout information. From the Customize the Activity screen, enter WearActivity for Activity Name shown and click on the Next button to proceed to the next step in the wizard:   Finally, click on the Finish button and the wizard will generate your project and after a few moments, the Android Studio window will appear with your project displayed. Summary In this article, we learned about three new APIs, DataAPI, NodeAPI, and MessageAPIs, and how we can use them and their associated methods to transmit information between the handheld mobile and the wearable. If, for whatever reason, the connected wearable node gets disconnected from the paired handheld device, the DataApi class is smart enough to try sending again automatically once the connection is reestablished. Resources for Article: Further resources on this subject: Speeding up Gradle builds for Android [article] Saying Hello to Unity and Android [article] Testing with the Android SDK [article]
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07 Aug 2015
6 min read
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Bootstrap in a Box

Packt
07 Aug 2015
6 min read
In this article written by Snig Bhaumik, author of the book Bootstrap Essentails, we explain the concept of Bootstrap, responsive design patterns, navigation patterns, and the different components that are included in Bootstrap. (For more resources related to this topic, see here.) Responsive design patterns Here are the few established and well-adopted patterns in Responsive Web Design: Fluid design: This is the most popular and easiest option for responsive design. In this pattern, larger screen multiple columns layout renders as a single column in a smaller screen in absolutely same sequence. Column drop: In this pattern also, the page gets rendered in a single column; however, the order of blocks gets altered. That means, if a content block is visible first in order in case of a larger screen, that might be rendered as second or third in case of a smaller screen. Layout shifter: This is a complex but powerful pattern where the whole layout of the screen contents gets altered in case of a smaller screen. This means that you need to develop different page layouts for large, medium, and small screens. Navigation patterns You should take care of the following things while designing a responsive web page. These are essentially the major navigational elements that you would concentrate on while developing a mobile friendly and responsive website: Menu bar Navigation/app bar Footer Main container shell Images Tabs HTML forms and elements Alerts and popups Embedded audios and videos, and so on You can see that there are lots of elements and aspects you need to take care of to create a fully responsive design. While all of these are achieved by using various features and technologies in CSS3, it is of course not an easy problem to solve without a framework that could help you do so. Precisely, you need a frontend framework that takes care of all the pains of technical responsive design implementation and releases you only for your brand and application design. Now, we introduce Bootstrap that would help you design and develop a responsive web design in a much optimized and efficient way. Introducing Bootstrap Simply put, Bootstrap is a frontend framework for faster and easier web development in the new standard of mobile-first philosophy. It uses HTML, CSS, and JavaScript. In August 2010, Twitter released Bootstrap as Open Source. There are quite a few similar frontend frameworks available in the industry, but Bootstrap is arguably the most popular framework in the lot. It is evident when we see Bootstrap is the most starred project in GitHub since 2012. Until now, you must be in a position to fathom why and where we need to use Bootstrap for web development; however, just to recap, here are the points in short. The mobile-first approach A responsive design Automatic browser support and handling Easy to adapt and get going What Bootstrap includes The following diagram demonstrates the overall structure of Bootstrap: CSS Bootstrap comes with fundamental HTML elements styled, global CSS classes, classes for advanced grid patterns, and lots of enhanced and extended CSS classes. For example, this is how the HTML global element is configured in Bootstrap CSS: html { font-family: sans-serif; -webkit-text-size-adjust: 100%; -ms-text-size-adjust: 100%; } This is how a standard HR HTML element is styled: hr { height: 0; -webkit-box-sizing: content-box; -moz-box-sizing: content-box; box-sizing: content-box; } Here is an example of new classes introduced in Bootstrap: .glyphicon { position: relative; top: 1px; display: inline-block; font-family: 'Glyphicons Halflings'; font-style: normal; font-weight: normal; line-height: 1; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; } Components Bootstrap offers a rich set of reusable and built-in components, such as breadcrumbs, progress bars, alerts, and navigation bars. The components are technically custom CSS classes specially crafted for the specific purpose. For example, if you want to create a breadcrumb in your page, you simply add a DIV tag in your HTML using Bootstrap’s breadcrumb class: <ol class="breadcrumb"> <li><a href="#">Home</a></li> <li><a href="#">The Store</a></li> <li class="active">Offer Zone</li> </ol> In the background (stylesheet), this Bootstrap class is used to create your breadcrumb: .breadcrumb { padding: 8px 15px; margin-bottom: 20px; list-style: none; background-color: #f5f5f5; border-radius: 4px; } .breadcrumb > li { display: inline-block; } .breadcrumb > li + li:before { padding: 0 5px; color: #ccc; content: "/ 0a0"; } .breadcrumb > .active { color: #777; } Please note that these set of code blocks are simply snippets. JavaScript Bootstrap framework comes with a number of ready-to-use JavaScript plugins. Thus, when you need to create Popup windows, Tabs, Carousels or Tooltips, and so on, you just use one of the prepackaged JavaScript plugins. For example, if you need to create a tab control in your page, you use this: <div role="tabpanel"> <ul class="nav nav-tabs" role="tablist"> <li role="presentation" class="active"><a href="#recent" aria-controls="recent" role="tab" data-toggle="tab">Recent Orders</a></li> <li role="presentation"><a href="#all" aria-controls="al" role="tab" data-toggle="tab">All Orders</a></li> <li role="presentation"><a href="#redeem" aria-controls="redeem" role="tab" data-toggle="tab">Redemptions</a></li> </ul>   <div class="tab-content"> <div role="tabpanel" class="tab-pane active" id="recent"> Recent Orders</div> <div role="tabpanel" class="tab-pane" id="all">All Orders</div> <div role="tabpanel" class="tab-pane" id="redeem">Redemption History</div> </div> </div> To activate (open) a tab, you write this JavaScript code: $('#profileTab li:eq(1) a').tab('show'); As you could guess by looking at the syntax of this JavaScript line that the Bootstrap JS plugins are built on top of jQuery. Thus, the JS code you would write for Bootstrap are also all based on jQuery. Customization Even though Bootstrap offers most (if not all) standard features and functionalities for Responsive Web Design, there might be several cases when you would want to customize and extend the framework. One of the very basic requirements for customization would be to deploy your own branding and color combinations (themes) instead of the Bootstrap default ones. There can be several such use cases where you would want to change the default behavior of the framework. Bootstrap offers very easy and stable ways to customize the platform. When you use the Bootstrap CSS, all the global and fundamental HTML elements automatically become responsive and would properly behave as the client device on which the web page is browsed. The built-in components are also designed to be responsive. As the developer, you shouldn’t be worried about how these advanced components would behave in different devices and client agents. Summary In this article we have discussed the basics of Bootstarp along with a brief explanation on the design patterns and the navigation patterns. Resources for Article: Further resources on this subject: Deep Customization of Bootstrap [article] The Bootstrap grid system [article] Creating a Responsive Magento Theme with Bootstrap 3 [article]
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07 Aug 2015
4 min read
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The Camera API

Packt
07 Aug 2015
4 min read
In this article by Purusothaman Ramanujam, the author of PhoneGap Beginner's Guide Third Edition, we will look at the Camera API. The Camera API provides access to the device's camera application using the Camera plugin identified by the cordova-plugin-camera key. With this plugin installed, an app can take a picture or gain access to a media file stored in the photo library and albums that the user created on the device. The Camera API exposes the following two methods defined in the navigator.camera object: getPicture: This opens the default camera application or allows the user to browse the media library, depending on the options specified in the configuration object that the method accepts as an argument cleanup: This cleans up any intermediate photo file available in the temporary storage location (supported only on iOS) (For more resources related to this topic, see here.) As arguments, the getPicture method accepts a success handler, failure handler, and optionally an object used to specify several camera options through its properties as follows: quality: This is a number between 0 and 100 used to specify the quality of the saved image. destinationType: This is a number used to define the format of the value returned in the success handler. The possible values are stored in the following Camera.DestinationType pseudo constants: DATA_URL(0): This indicates that the getPicture method will return the image as a Base64-encoded string FILE_URI(1): This indicates that the method will return the file URI NATIVE_URI(2): This indicates that the method will return a platform-dependent file URI (for example, assets-library:// on iOS or content:// on Android) sourceType: This is a number used to specify where the getPicture method can access an image. The following possible values are stored in the Camera.PictureSourceType pseudo constants: PHOTOLIBRARY (0), CAMERA (1), and SAVEDPHOTOALBUM (2): PHOTOLIBRARY: This indicates that the method will get an image from the device's library CAMERA: This indicates that the method will grab a picture from the camera SAVEDPHOTOALBUM: This indicates that the user will be prompted to select an album before picking an image allowEdit: This is a Boolean value (the value is true by default) used to indicate that the user can make small edits to the image before confirming the selection; it works only in iOS. encodingType: This is a number used to specify the encoding of the returned file. The possible values are stored in the Camera.EncodingType pseudo constants: JPEG (0) and PNG (1). targetWidth and targetHeight: These are the width and height in pixels, to which you want the captured image to be scaled; it's possible to specify only one of the two options. When both are specified, the image will be scaled to the value that results in the smallest aspect ratio (the aspect ratio of an image describes the proportional relationship between its width and height). mediaType: This is a number used to specify what kind of media files have to be returned when the getPicture method is called using the Camera.PictureSourceType.PHOTOLIBRARY or Camera.PictureSourceType.SAVEDPHOTOALBUM pseudo constants as sourceType; the possible values are stored in the Camera.MediaType object as pseudo constants and are PICTURE (0), VIDEO (1), and ALLMEDIA (2). correctOrientation: This is a Boolean value that forces the device camera to correct the device orientation during the capture. cameraDirection: This is a number used to specify which device camera has to be used during the capture. The values are stored in the Camera.Direction object as pseudo constants and are BACK (0) and FRONT (1). popoverOptions: This is an object supported on iOS to specify the anchor element location and arrow direction of the popover used on iPad when selecting images from the library or album. saveToPhotoAlbum: This is a Boolean value (the value is false by default) used in order to save the captured image in the device's default photo album. The success handler receives an argument that contains the URI to the file or data stored in the file's Base64-encoded string, depending on the value stored in the encodingType property of the options object. The failure handler receives a string containing the device's native code error message as an argument. Similarly, the cleanup method accepts a success handler and a failure handler. The only difference between the two is that the success handler doesn't receive any argument. The cleanup method is supported only on iOS and can be used when the sourceType property value is Camera.PictureSourceType.CAMERA and the destinationType property value is Camera.DestinationType.FILE_URI. Summary In this article, we looked at the various properties available with the Camera API. Resources for Article: Further resources on this subject: Geolocation – using PhoneGap features to improve an app's functionality, write once use everywhere [article] Using Location Data with PhoneGap [article] iPhone JavaScript: Installing Frameworks [article]
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Packt
07 Aug 2015
9 min read
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NLTK for hackers

Packt
07 Aug 2015
9 min read
In this article written by Nitin Hardeniya, author of the book NLTK Essentials, we will learn that "Life is short, we need Python" that's the mantra I follow and truly believe in. As fresh graduates, we learned and worked mostly with C/C++/JAVA. While these languages have amazing features, Python has a charm of its own. The day I started using Python I loved it. I really did. The big coincidence here is that I finally ended up working with Python during my initial projects on the job. I started to love the kind of datastructures, Libraries, and echo system Python has for beginners as well as for an expert programmer. (For more resources related to this topic, see here.) Python as a language has advanced very fast and spatially. If you are a Machine learning/ Natural language Processing enthusiast, then Python is 'the' go-to language these days. Python has some amazing ways of dealing with strings. It has a very easy and elegant coding style, and most importantly a long list of open libraries. I can go on and on about Python and my love for it. But here I want to talk about very specifically about NLTK (Natural Language Toolkit), one of the most popular Python libraries for Natural language processing. NLTK is simply awesome, and in my opinion,it's the best way to learn and implement some of the most complex NLP concepts. NLTK has variety of generic text preprocessing tool, such as Tokenization, Stop word removal, Stemming, and at the same time,has some very NLP-specific tools,such as Part of speech tagging, Chunking, Named Entity recognition, and dependency parsing. NLTK provides some of the easiest solutions to all the above stages of NLP and that's why it is the most preferred library for any text processing/ text mining application. NLTK not only provides some pretrained models that can be applied directly to your dataset, it also provides ways to customize and build your own taggers, tokenizers, and so on. NLTK is a big library that has many tools available for an NLP developer. I have provided a cheat-sheet of some of the most common steps and their solutions using NLTK. In our book, NLTK Essentials, I have tried to give you enough information to deal with all these processing steps using NLTK. To show you the power of NLTK, let's try to develop a very easy application of finding topics in the unstructured text in a word cloud. Word CloudNLTK Instead of going further into the theoretical aspects of natural language processing, let's start with a quick dive into NLTK. I am going to start with some basic example use cases of NLTK. There is a good chance that you have already done something similar. First, I will give a typical Python programmer approach and then move on to NLTK for a much more efficient, robust, and clean solution. We will start analyzing with some example text content: >>>import urllib2>>># urllib2 is use to download the html content of the web link>>>response = urllib2.urlopen('http://python.org/')>>># You can read the entire content of a file using read() method>>>html = response.read()>>>print len(html)47020 For the current example, I have taken the content from Python's home page: https://www.python.org/. We don't have any clue about the kind of topics that are discussed in this URL, so let's say that we want to start an exploratory data analysis (EDA). Typically in a text domain, EDA can have many meanings, but will go with a simple case of what kinds of terms dominate the documents. What are the topics? How frequent are they? The process will involve some level of preprocessing we will try to do this in a pure Python wayand then we will do it using NLTK. Let's start with cleaning the html tags. One way to do this is to select just tokens, including numbers and character. Anybody who has worked with regular expression should be able to convert html string into a list of tokens: >>># regular expression based split the string>>>tokens = [tok for tok in html.split()]>>>print "Total no of tokens :"+ str(len(tokens))>>># first 100 tokens>>>print tokens[0:100]Total no of tokens :2860['<!doctype', 'html>', '<!--[if', 'lt', 'IE', '7]>', '<html', 'class="no-js', 'ie6', 'lt-ie7', 'lt-ie8', 'lt-ie9">', '<![endif]-->', '<!--[if', 'IE', '7]>', '<html', 'class="no-js', 'ie7', 'lt-ie8', 'lt-ie9">', '<![endif]-->', ''type="text/css"', 'media="not', 'print,', 'braille,' ...] As you can see, there is an excess of html tags and other unwanted characters when we use the preceding method. A cleaner version of the same task will look something like this: >>>import re>>># using the split function https://docs.python.org/2/library/re.html>>>tokens = re.split('W+',html)>>>print len(tokens)>>>print tokens[0:100]5787['', 'doctype', 'html', 'if', 'lt', 'IE', '7', 'html', 'class', 'no', 'js', 'ie6', 'lt', 'ie7', 'lt', 'ie8', 'lt', 'ie9', 'endif', 'if', 'IE', '7', 'html', 'class', 'no', 'js', 'ie7', 'lt', 'ie8', 'lt', 'ie9', 'endif', 'if', 'IE', '8', 'msapplication', 'tooltip', 'content', 'The', 'official', 'home', 'of', 'the', 'Python', 'Programming', 'Language', 'meta', 'name', 'apple' ...] This looks much cleaner now. But still you can do more; I leave it to you to try to remove as much noise as you can. You can still look for word length as a criteria and remove words that have a length one—it will remove elements,such as 7, 8, and so on, which are just noise in this case. Now let's go to NLTK for the same task. There is a function called clean_html() that can do all the work we were looking for: >>>import nltk>>># http://www.nltk.org/api/nltk.html#nltk.util.clean_html>>>clean = nltk.clean_html(html)>>># clean will have entire string removing all the html noise>>>tokens = [tok for tok in clean.split()]>>>print tokens[:100]['Welcome', 'to', 'Python.org', 'Skip', 'to', 'content', '&#9660;', 'Close', 'Python', 'PSF', 'Docs', 'PyPI', 'Jobs', 'Community', '&#9650;', 'The', 'Python', 'Network', '&equiv;', 'Menu', 'Arts', 'Business' ...] Cool, right? This definitely is much cleaner and easier to do. No analysis in any EDA can start without distribution. Let's try to get the frequency distribution. First, let's do it the Python way, then I will tell you the NLTK recipe. >>>import operator>>>freq_dis={}>>>for tok in tokens:>>>    if tok in freq_dis:>>>        freq_dis[tok]+=1>>>    else:>>>        freq_dis[tok]=1>>># We want to sort this dictionary on values ( freq in this case )>>>sorted_freq_dist= sorted(freq_dis.items(), key=operator.itemgetter(1), reverse=True)>>> print sorted_freq_dist[:25][('Python', 55), ('>>>', 23), ('and', 21), ('to', 18), (',', 18), ('the', 14), ('of', 13), ('for', 12), ('a', 11), ('Events', 11), ('News', 11), ('is', 10), ('2014-', 10), ('More', 9), ('#', 9), ('3', 9), ('=', 8), ('in', 8), ('with', 8), ('Community', 7), ('The', 7), ('Docs', 6), ('Software', 6), (':', 6),  ('3:', 5), ('that', 5), ('sum', 5)] Naturally, as this is Python's home page, Python and the >>> interpreters are the most common terms, also giving a sense about the website. A better and efficient approach is to use NLTK's FreqDist() function. For this, we will take a look at the same code we developed before: >>>import nltk>>>Freq_dist_nltk=nltk.FreqDist(tokens)>>>print Freq_dist_nltk>>>for k,v in Freq_dist_nltk.items():>>>    print str(k)+':'+str(v)<FreqDist: 'Python': 55, '>>>': 23, 'and': 21, ',': 18, 'to': 18, 'the': 14, 'of': 13, 'for': 12, 'Events': 11, 'News': 11, ...>Python:55>>>:23and:21,:18to:18the:14of:13for:12Events:11News:11 Let's now do some more funky things. Let's plot this: >>>Freq_dist_nltk.plot(50, cumulative=False)>>># below is the plot for the frequency distributions We can see that the cumulative frequency is growing, and at words such as other and frequency 400, the curve is going into long tail. Still, there is some noise, and there are words such asthe, of, for, and =. These are useless words, and there is a terminology for these words. These words are stop words,such asthe, a, and an. Article pronouns are generally present in most of the documents; hence, they are not discriminative enough to be informative. In most of the NLP and information retrieval tasks, people generally remove stop words. Let's go back again to our running example: >>>stopwords=[word.strip().lower() for word in open("PATH/english.stop.txt")]>>>clean_tokens=[tok for tok in tokens if len(tok.lower())>1 and (tok.lower() not in stopwords)]>>>Freq_dist_nltk=nltk.FreqDist(clean_tokens)>>>Freq_dist_nltk.plot(50, cumulative=False) This looks much cleaner now! After finishing this much, you should be able to get something like this using word cloud: Please go to http://www.wordle.net/advanced for more word clouds. Summary To summarize, this article was intended to give you a brief introduction toNatural Language Processing. The book does assume some background in NLP andprogramming in Python, but we have tried to give a very quick head start to Pythonand NLP. Resources for Article: Further resources on this subject: Hadoop Monitoring and its aspects [Article] Big Data Analysis (R and Hadoop) [Article] SciPy for Signal Processing [Article]
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07 Aug 2015
19 min read
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Storage Ergonomics

Packt
07 Aug 2015
19 min read
In this article by Saurabh Grover, author of the book Designing Hyper-V Solutions, we will be discussing the last of the basics to get you equipped to create and manage a simple Hyper-V structure. No server environment, physical or virtual, is complete without a clear consideration and consensus over the underlying storage. In this article, you will learn about the details of virtual storage, how to differentiate one from the other, and how to convert one to the other and vice versa. We will also see how Windows Server 2012 R2 removes dependencies on raw device mappings by way of pass-through or iSCSI LUN, which were required for guest clustering. VHDX can now be shared and delivers better results than pass-through disks. There are more merits to VHDX than the former, as it allows you to extend the size even if the virtual machine is alive. Previously, Windows Server 2012 added a very interesting facet for storage virtualization in Hyper-V when it introduced virtual SAN, which adds a virtual host bus adapter (HBA) capability to a virtual machine. This allows a VM to directly view the fibre channel SAN. This in turn allows FC LUN accessibility to VMs and provides you with one more alternative for shared storage for guest clustering. Windows Server 2012 also introduced the ability to utilize the SMI-S capability, which was initially tested on System Center VMM 2012. Windows 2012 R2 carries the torch forward, with the addition of new capabilities. We will discuss this feature briefly in this article. In this article, you will cover the following: Two types of virtual disks, namely VHD and VHDX Merits of using VHDX from Windows 2012 R2 onwards Virtual SAN storage Implementing guest clustering using shared VHDX Getting an insight into SMI-S (For more resources related to this topic, see here.) Virtual storage A virtual machine is a replica of a physical machine in all rights and with respect to the building components, regardless of the fact that it is emulated, resembles, and delivers the same performance as a physical machine. Every computer ought to have storage for the OS or application loading. This condition applies to virtual machines as well. If VMs are serving as independent servers for roles such as domain controller or file server, where the server needs to maintain additional storage apart from the OS, the extended storage can be extended for domain user access without any performance degradation. Virtual machines can benefit from multiple forms of storage, namely VHD/VHDX, which are file-based storage; iSCSI LUNs; pass-through LUNs, which are raw device mappings; and of late, virtual-fibre-channel-assigned LUNs. There have been enhancements to each of these, and all of these options have a straightforward implementation procedure. However, before you make a selection, you should identify the use case according to your design strategy and planned expenditure. In the following section, we will look at the storage choices more closely. VHD and VHDX VHD is the old flag bearer for Microsoft virtualization ever since the days of virtual PC and virtual server. The same was enhanced and employed in early Hyper-V releases. However, as a file-based storage that gets mounted as a normal storage for a virtual machine, VHD had its limitations. VHDX, a new feature addition to Windows Server 2012, was built further upon the limitations of its predecessor and provides greater storage capacity, support for large sector disks, and better protection against corruption. In the current release of Windows Server 2012 R2, VHDX has been bundled with more ammo. VHDX packed a volley of feature enhancements when it was initially launched, and with Windows Server 2012 R2, Microsoft only made it better. If we compare the older, friendlier version of VHD with VHDX, we can draw the following inferences: Size factor: VHD had an upper size limit of 2 TB, while VHDX gives you a humungous maximum capacity of 64 TB. Large disk support: With the storage industry progressing towards 4 KB sector disks from the 512 bytes sector, for applications that still may depend on the older sector format, there are two offerings from the disk alignment perspective: native 4 KB disk and 512e (or 512 byte emulation disks). The operating system, depending on whether it supports native 4 KB disk or not, will either write 4 KB chunks of data or inject 512 bytes of data into a 4 KB sector. The process of injecting 512 bytes into a 4 KB sector is called RMW, or Read-Write-Modify. VHDs are generically supported on 512e disks. Windows Server 2012 and R2 both support native 4 KB disks. However, the VHD driver has a limitation; it cannot open VHD files on physical 4 KB disks. This limitation is checked by enabling VHD to be aligned to 4 KB and RMW ready, but if you are migrating from the older Hyper-V platform, you will need to convert it accordingly. VHDX, on the other hand, is the "superkid". It can be used on all disk forms, namely 512, 512e, and the native 4 KB disk as well, without any RMW dependency. Data corruption safety: In the event of power outages or failures, the possibility of data corruption is reduced with VHDX. Metadata inside the VHDX is updated via a logging process that ensures that the allocations inside VHDX are committed successfully. Offloaded data transfers (ODX): With Windows Server 2012 Hyper-V supporting this feature, data transfer and moving and sizing of virtual disks can be achieved at the drop of a hat, without host server intervention. The basic prerequisite for utilizing this feature is to host the virtual machines on ODX-capable hardware. Thereafter, Windows Server 2012 self-detects and enables the feature. Another important clause is that virtual disks (VHDX) should be attached to the SCSI, not IDE. TRIM/UNMAP: Termed by Microsoft in its documentation as efficiency in representing data, this feature works in tandem with thin provisioning. It adds the ability to allow the underlying storage to reclaim space and maintain it optimally small. Shared VHDX: This is the most interesting feature in the collection released with Windows Server 2012 R2. It made guest clustering (failover clustering in virtual machines) in Hyper-V a lot simpler. With Windows Server 2012, you could set up a guest cluster using virtual fibre channel or iSCSI LUN. However, the downside was that the LUN was exposed to the user of the virtual machine. Shared VHDX proves to be the ideal shared storage. It gives you the benefit of storage abstraction, flexibility, and faster deployment of guest clusters, and it can be stored on an SMB share or a cluster-shared volume (CSV). Now that we know the merits of using VHDX over VHD, it is important to realize that either of the formats can be converted into the other and can be used under various types of virtual disks, allowing users to decide a trade-off between performance and space utilization. Virtual disk types Beyond the two formats of virtual hard disks, let's talk about the different types of virtual hard disks and their utility as per the virtualization design. There are three types of virtual hard disks, namely dynamically expanding, fixed-size, and differencing virtual hard disks: Dynamically expanding: Also called a dynamic virtual hard disk, this is the default type. It gets created when you create a new VM or a new VHD/VHDX. This is Hyper-V's take on thin provisioning. The VHD/VHDX file will start off from a small size and gradually grow up to the maximum defined size for the file as and when chunks of data get appended or created inside the OSE (short for operating system environment) hosted by the virtual disk. This disk type is quite beneficial, as it prevents storage overhead and utilizes as much as required, rather than committing the entire block. However, due to the nature of the virtual storage, as it spawns in size, the actual file gets written in fragments across the Hyper-V CSV or LUN (physical storage). Hence, it affects the performance of the disk I/O operations of the VM. Fixed size: As the name indicates, the virtual disk type commits the same block size on the physical storage as its defined size. In other words, if you have specified a fixed size 1 TB, it will create a 1 TB VHDX file in the storage. The creation of a fixed size takes a considerable amount of time, commits space on the underlying storage, and does allow SAN thin provisioning to reclaim it, somewhat like whitespaces in a database. The advantage of using this type is that it delivers amazing read performance and heavy workloads from SQL, and exchange can benefit from it. Differencing: This is the last of the lot, but quite handy as an option when it comes to quick deployment of virtual machines. This is by far an unsuitable option, unless employed for VMs with a short lifespan, namely pooled VDI (short for virtual desktop infrastructure) or lab testing. The idea behind the design is to have a generic virtual operating system environment (VOSE) in a shut down state at a shared location. The VHDX of the VOSE is used as a parent or root, and thereafter, multiple VMs can be spawned with differencing or child virtual disks that use the generalized OS from the parent and append changes or modifications to the child disk. So, the parent stays unaltered and serves as a generic image. It does not grow in size; on the contrary, the child disk keeps on growing as and when data is added to the particular VM. Unless used for short-lived VMs, the long-running VMs could enter an outage state or may be performance-stricken soon due to the unpredictable growth pattern of a differencing disk. Hence, these should be avoided for server virtual machines without even a second thought. Virtual disk operations Now we will apply all of the knowledge gained about virtual hard disks, and check out what actions and customizations we can perform on them. Creating virtual hard disks This goal can be achieved in different ways: You can create a new VHD when you are creating a new VM, using the New Virtual Machine Wizard. It picks up the VHDX as the default option. You can also launch the New Virtual Hard Disk Wizard from a virtual machine's settings. This can be achieved by PowerShell cmdlets as well:New-VHD You may employ the Disk Management snap-in to create a new VHD as well. The steps to create a VHD here are pretty simple: In the Disk Management snap-in, select the Action menu and select Create VHD, like this: Figure 5-1: Disk Management – Create VHD This opens the Create and Attach Virtual Hard Disk applet. Specify the location to save the VHD at, and fill in Virtual hard disk format and Virtual hard disk type as depicted here in figure 5-2: Figure 5-2: Disk Management – Create and Attach Virtual Hard Disk The most obvious way to create a new VHD/VHDX for a VM is by launching New Virtual Hard Disk Wizard from the Actions pane in the Hyper-V Manager console. Click on New and then select the Hard Disk option. It will take you to the following set of screens: On the Before You Begin screen, click on Next, as shown in this screenshot: Figure 5-3: New Virtual Hard Disk Wizard – Create VHD The next screen is Choose Disk Format, as shown in figure 5-4. Select the relevant virtual hard disk format, namely VHD or VHDX, and click on Next. Figure 5-4: New Virtual Hard Disk Wizard – Virtual Hard Disk Format In the screen for Choose Disk Type, select the relevant virtual hard disk type and click on Next, as shown in the following screenshot: Figure 5-5: New Virtual Hard Disk Wizard– Virtual Hard Disk Type The next screen, as shown in figure 5-6, is Specify Name and Location. Update the Name and Location fields to store the virtual hard disk and click on Next. Figure 5-6: New Virtual Hard Disk Wizard – File Location The Configure Disk screen, shown in figure 5-7, is an interesting one. If needs be, you can convert or copy the content of a physical storage (local, LUN, or something else) to the new virtual hard disk. Similarly, you can copy the content from an older VHD file to the Windows Server 2012 or R2 VHDX format. Then click on Next. Figure 5-7: New Virtual Hard Disk Wizard – Configure Disk On the Summary screen, as shown in the following screenshot, click on Finish to create the virtual hard disk: Figure 5-8: New Virtual Hard Disk Wizard – Summary Editing virtual hard disks There may be one or more reasons for you to feel the need to modify a previously created virtual hard disk to suit a purpose. There are many available options that you may put to use, given a particular virtual disk type. Before you edit a VHDX, it's a good practice to inspect the VHDX or VHD. The Inspect Disk option can be invoked from two locations: from the VM settings under the IDE or SCSI controller, or from the Actions pane of the Hyper-V Manager console. Also, don't forget how to do this via PowerShell: Get-VHD -Path "E:Hyper-VVirtual hard disks1.vhdx" You may now proceed with editing a virtual disk. Again, the Edit Disk option can be invoked in exactly the same fashion as Inspect Disk. When you edit a VHDX, you are presented with four options, as shown in figure 5-9. It may sound obvious, but not all the options are for all the disk types: Compact: This operation is used to reduce or compact the size of a virtual hard disk, though the preset capacity remains the same. A dynamic disk, or differencing disk, grows as data elements are added, though deletion of the content does not automatically reclaim the storage capacity. Hence, a manual compact operation becomes imperative reduce the file size. PowerShell cmdlet can also do this trick, as follows: Optimize-VHD Convert: This is an interesting one, and it almost makes you change your faith. As the name indicates, this operation allows you to convert one virtual disk type to another and vice versa. You can also create a new virtual disk of the desired format and type at your preferred location. The PowerShell construct used to help you achieve the same goal is as follows: Convert-VHD Expand: This operation comes in handy, similar to Extend a LUN. You end up increasing the size of a virtual hard disk, which happens visibly fast for a dynamic disk and a bit slower for its fixed-size cousins. After this action, you have to perform the follow-up action inside the virtual machine to increase the volume size from disk management. Now, for the PowerShell code: Resize-VHD Merge: This operation is disk-type-specific—differencing virtual disks. It allows two different actions. You can either merge the differencing disk with the original parent, or create a new merged VHD out of all the contributing VHDs, namely the parent and the child or the differencing disk. The latter is the preferred way of doing it, as in utmost probability, there would be more than differencing to a parent. In PowerShell, the alternative the cmdlet is this: Merge-VHD Figure 5-9: Edit Virtual Hard Disk Wizard – Choose Action Pass-through disks As the name indicates, these are physical LUNs or hard drives passed on from the Hyper-V hosts, and can be assigned to a virtual machine as a standard disk. A once popular method on older Hyper-V platforms, this allowed the VM to harness the full potential of the raw device bypassing the Hyper-V host filesystem and also not getting restricted by the 2 TB limit of VHDs. A lot has changed over the years, as Hyper-V has matured into a superior virtualization platform and introduced VHDX, which went past the size limitation. with Windows Server 2012 R2 can be used as a shared storage for Hyper-V guest clusters. There are, however, demerits to this virtual storage. When you employ a pass-through disk, the virtual machine configuration file is stored separately. Hence, the snapshotting becomes unknown to this setup. You would not be able to utilize the dynamic disk's or differential disk's abilities here too. Another challenge of using this form of virtual storage is that when using a VSS-based backup, the VSS writer ignores the pass-through and iSCSI LUN. Hence, a complex backup plan has to be implemented by involving a running backup within VM and on the virtualization host separately. The following are steps, along with a few snapshots, that show you how to set up a pass-through disk: Present a LUN to the Hyper-V host. Confirm the LUN in Disk Management and ensure that it stays in the Offline State and as Not Initialized. Figure 5-10: Hyper-V Host Disk Management In Hyper-V Manager, right-click on the VM you wish to assign the pass-through to and select Settings. Figure 5-11: VM Settings – Pass-through disk placement Select SCSI Controller (or IDE in the case of Gen-1 VM) and then select the Physical hard disk option, as shown in the preceding screenshot. In the drop-down menu, you will see the raw device or LUN you wish to assign. Select the appropriate option and click on OK. Check Disk Management within the virtual machine to confirm that the disk has visibility. Figure 5-12: VM Disk Management – Pass-through Assignment Bring it online and initialize. Figure 5-13: VM Disk Management – Pass-through Initialization As always the preceding path can be chalked out with the help of a PowerShell cmdlet: Add-VMHardDiskDrive -VMName VM5 –ControllerType SCSI – ControllerNumber 0 –ControllerLocation 2 –DiskNumber 3 Virtual fibre channel Let's move on to the next big offering in Windows Server 2012 and R2 Hyper-V Server. There was pretty much a clamor for direct FC connectivity to virtual machines, as pass-through disks were supported only via iSCSI LUNs (with some major drawbacks not with FC). Also, needless to say, FC is faster. Enterprises with high-performance workloads relying on the FC SAN refrained from virtualizing or migrating to the cloud. Windows Server 2012 introduced the virtual fibre channel SAN ability in Hyper-V, which extended the HBA (short for host bus adapter) abilities to a virtual machine, granting them a WWN (short for world wide node name) and allowing access to a fibre channel SAN over a virtual SAN. The fundamental principle behind the virtual SAN is the same as the Hyper-V virtual switch, wherein you create a virtual SAN that hooks up to the SAN fabric over the physical HBA of the Hyper-V host. The virtual machine has new synthetic hardware for the last piece. It is called a virtual host bus adapter or vHBA, which gets its own set of WWNs, namely WWNN (node name) and WWPN (port name). The WWN is to the FC protocol as MAC is to the Ethernet. Once the WWNs are identified at the fabric and the virtual SAN, the storage admins can set up zoning and present the LUN to the specific virtual machine. The concept is straightforward, but there are prerequisites that you will need to ensure are in place before you can get down to the nitty-gritty of the setup: One or more Windows Server 2012 or R2 Hyper-V hosts. Hosts should have one or more FC HBAs with the latest drivers, and should support the virtual fibre channel and NPIV. NPIV may be disabled at the HBA level (refer to the vendor documentation prior to deployment). The same can be enabled using command-line utilities or GUI-based such as OneCommand manager, SANSurfer, and so on. NPIV should be enabled on the SAN fabric or actual ports. Storage arrays are transparent to NPIV, but they should support devices that present LUNs. Supported guest operating systems for virtual SAN are Windows 2008, Windows 2008 R2, Windows 2012, and Windows 2012 R2. The virtual fibre channel does not allow boot from SAN, unlike pass-through disks. We are now done with the prerequisites! Now, let's look at two important aspects of SAN infrastructure, namely NPIV and MPIO. N_Port ID virtualization (NPIV) An ANSI T11 standard extension, this feature allows virtualization of the N_Port (WWPN) of an HBA, allowing multiple FC initiators to share a single HBA port. The concept is popular and is widely accepted and promoted by different vendors. Windows Server 2012 and R2 Hyper-V utilizes this feature to the best, wherein each virtual machine partaking in the virtual SAN gets assigned a unique WWPN and access to the SAN over a physical HBA spawning its own N_Port. Zoning follows next, wherein the fabric can have the zone directed to the VM WWPN. This attribute leads to a very small footprint, and thereby, easier management and operational and capital expenditure. Summary It is going to be quite a realization that we have covered almost all the basic attributes and aspects required for a simple Windows Server 2012 R2 Hyper-V infrastructure setup. If we revise the contents, we will notice this: we started off in this article by understanding and defining the purpose of virtual storage, and what the available options are for storage to be used with a virtual machine. We reviewed various virtual hard disk types, formats, and associated operations that may be required to customize a particular type or modify it accordingly. We recounted how the VHDX format is superior to its predecessor VHD and which features were added with the latest Window Server releases, namely 2012 and 2012 R2. We discussed shared VHDX and how it can be used as an alternative to the old-school iSCSI or FC LUN as a shared storage for Windows guest clustering. Pass-through disks are on their way out, and we all know the reason why. The advent of the virtual fibre channel with Windows Server 2012 has opened the doors for virtualization of high-performance workloads relying heavily on FC connectivity, which until now was a single reason and enough of a reason to decline consolidation of these workloads. Resources for Article: Further resources on this subject: Hyper-V Basics [article] Getting Started with Hyper-V Architecture and Components [article] Hyper-V building blocks for creating your Microsoft virtualization platform [article]
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Packt
06 Aug 2015
18 min read
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Detecting Touchscreen Gestures

Packt
06 Aug 2015
18 min read
In this article by Kyle Mew author of the book, Android 5 Programming by Example, we will learn how to: Add a GestureDetector to a view Add an OnTouchListener and an OnGestureListener Detect and refine fling gestures Use the DDMS Logcat to observe the MotionEvent class Edit the Logcat filter configuration Simplify code with a SimpleOnGestureListener Add a GestureDetector to an Activity Edit the Manifest to control launch behavior Hide UI elements Create a splash screen Lock screen orientation (For more resources related to this topic, see here.) Adding a GestureDetector to a view Together, view.GestureDetector and view.View.OnTouchListener are all that are required to provide our ImageView with gesture functionality. The listener contains an onTouch() callback that relays each MotionEvent to the detector. We are going to program the large ImageView so that it can display a small gallery of related pictures that can be accessed by swiping left or right on the image. There are two steps to this task as, before we implement our gesture detector, we need to provide the data for it to work on. Adding the gallery data As this app is for demonstration and learning purposes, and so we can progress as quickly as possible, we will only provide extra images for one or two of the ancient sites in the project. Here is how it's done: Open the Ancient Britain project. Open the MainData.java file. Add the following arrays: static Integer[] hengeArray = {R.drawable.henge_large, R.drawable.henge_2, R.drawable.henge_3, R.drawable.henge_4}; static Integer[] horseArray = {}; static Integer[] wallArray = {R.drawable.wall_large, R.drawable.wall_2}; static Integer[] skaraArray = {}; static Integer[] towerArray = {}; static Integer[][] galleryArray = {hengeArray, horseArray, wallArray, skaraArray, towerArray}; Either download the project files from the Packt website or find four of your own images (around 640 x 480 px). Name them henge_2, henge_3, henge_4, and wall_2 and place them in your res/drawable directory. This is all very straightforward, and the code that will accompany it allows you to have individual arrays of any length. This is all we need to add to our gallery data. Now, we need to code our GestureDetector and OnTouchListener. Adding the GestureDetector Along with the OnTouchListener that we will define for our ImageView, the GestureDetector has its own listeners. Here we will use GestureDetector.OnGestureListener to detect a fling gesture and collect the MotionEvent that describe it. Follow these steps to program your ImageView to respond to fling gestures: Open the DetailActivity.java file. Declare the following class fields: private static final int MIN_DISTANCE = 150; private static final int OFF_PATH = 100; private static final int VELOCITY_THRESHOLD = 75; private GestureDetector detector; View.OnTouchListener listener; private int ImageIndex; In the onCreate() method assigns both the detector and listener like this: detector = new GestureDetector(this, new GalleryGestureDetector()); listener = new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { return detector.onTouchEvent(event); } }; Beneath this, add the following line: ImageIndex = 0; Beneath the line detailImage = (ImageView) findViewById(R.id.detail_image);, add the following line: detailImage.setOnTouchListener(listener); Create the following inner class: class GalleryGestureDetector implements GestureDetector.OnGestureListener { } Before dealing with the errors this generates, add the following field to the class: private int item; { item = MainActivity.currentItem; } Click anywhere on the line registering the error and press Alt + Enter. Then select Implement Methods, making sure that you have the Copy JavaDoc and Insert @Override boxes checked. Complete the onDown() method like this: @Override public boolean onDown(MotionEvent e) { return true; } Fill in the onShowPress() method: @Override public void onShowPress(MotionEvent e) { detailImage.setElevation(4); } Then fill in the onFling() method: @Override public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) { if (Math.abs(event1.getY() - event2.getY()) > OFF_PATH) return false; if (MainData.galleryArray[item].length != 0) { // Swipe left if (event1.getX() - event2.getX() > MIN_DISTANCE && Math.abs(velocityX) > VELOCITY_THRESHOLD) { ImageIndex++; if (ImageIndex == MainData.galleryArray[item].length) ImageIndex = 0; detailImage.setImageResource(MainData .galleryArray[item][ImageIndex]); } else { // Swipe right if (event2.getX() - event1.getX() > MIN_DISTANCE && Math.abs(velocityX) > VELOCITY_THRESHOLD) { ImageIndex--; if (ImageIndex < 0) ImageIndex = MainData.galleryArray[item].length - 1; detailImage.setImageResource(MainData .galleryArray[item][ImageIndex]); } } } detailImage.setElevation(0); return true; } Test the project on an emulator or handset. The process of gesture detection in the preceding code begins when the OnTouchListener listener's onTouch() method is called. It then passes that MotionEvent to our gesture detector class, GalleryGestureDetector, which monitors motion events, sometimes stringing them together and timing them until one of the recognized gestures is detected. At this point, we can enter our own code to control how our app responds as we did here with the onDown(), onShowPress(), and onFling() callbacks. It is worth taking a quick look at these methods in turn. It may seem, at the first glance, that the onDown() method is redundant; after all, it's the fling gesture that we are trying to catch. In fact, overriding the onDown() method and returning true from it is essential in all gesture detections as all the gestures begin with an onDown() event. The purpose of the onShowPress() method may also appear unclear as it seems to do a little more than onDown(). As the JavaDoc states, this method is handy for adding some form of feedback to the user, acknowledging that their touch has been received. The Material Design guidelines strongly recommend such feedback and here we have raised the view's elevation slightly. Without including our own code, the onFling() method will recognize almost any movement across the bounding view that ends in the user's finger being raised, regardless of direction or speed. We do not want very small or very slow motions to result in action; furthermore, we want to be able to differentiate between vertical and horizontal movement as well as left and right swipes. The MIN_DISTANCE and OFF_PATH constants are in pixels and VELOCITY_THRESHOLD is in pixels per second. These values will need tweaking according to the target device and personal preference. The first MotionEvent argument in onFling() refers to the preceding onDown() event and, like any MotionEvent, its coordinates are available through its getX() and getY() methods. The MotionEvent class contains dozens of useful classes for querying various event properties—for example, getDownTime(), which returns the time in milliseconds since the current onDown() event. In this example, we used GestureDetector.OnGestureListener to capture our gesture. However, the GestureDetector has three such nested classes, the other two being SimpleOnGestureListener and OnDoubleTapListener. SimpleOnGestureListener provides a more convenient way to detect gestures as we only need to implement those methods that relate to the gestures we are interested in capturing. We will shortly edit our Activity so that it implements the SimpleOnGestureListener instead, allowing us to tidy our code and remove the four callbacks that we do not need. The reason for taking this detour, rather than applying the simple listener to begin with, was to get to see all of the gestures available to us through a gesture listener and demonstrate how useful JavaDoc comments can be, particularly if we are new to the framework. For example, take a look at the following screenshot: Another very handy tool is the Dalvik Debug Monitor Server (DDMS), which allows us to see what is going on inside our apps while they are running. The workings of our gesture listener are a good place to do this as most of its methods operate invisibly. Viewing gesture activity with DDMS To view the workings of our OnGestureListener with DDMS, we need to first create a tag to identify our messages and then a filter to view them. The following steps demonstrate how to do this: Open the DetailActivity.java file. Declare the following constant: private static final String DEBUG_TAG = "tag"; Add the following line inside the onDown() method: Log.d(DEBUG_TAG, "onDown"); Add the line Log.d(DEBUG_TAG, "onShowPress"); to the onShowPress() method and do the same for each of our OnGestureDetector methods. Add the following lines to the appropriate clauses in onFling(): Log.d(DEBUG_TAG, "left"); Log.d(DEBUG_TAG, "right"); Open the Android DDMS pane from the Android tab at the bottom of the window or by pressing Alt + 6. If logcat is not visible, it can be opened with the icon to the right of the top-right drop-down menu. Click on this drop-down menu and select Edit Filter Configuration. Complete the dialog as shown in the following screenshot: You can now run the project on a handset or emulator and view, in the Logcat, which gestures are being triggered and how. Your output should resemble the one here: 02-17 14:39:00.990 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onDown 02-17 14:39:01.039 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onSingleTapUp 02-17 14:39:03.503 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onDown 02-17 14:39:03.601 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onShowPress 02-17 14:39:04.101 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onLongPress 02-17 14:39:10.484 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onDown 02-17 14:39:10.541 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onScroll 02-17 14:39:11.091 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onScroll 02-17 14:39:11.232 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onFling 02-17 14:39:11.680 1430- 1430/com.example.kyle.ancientbritain D/tag﹕ right 02-17 14:39:01.039   1430- 1430/com.example.kyle.ancientbritain D/tag﹕ onSingleTapUp DDMS is an invaluable tool when it comes to debugging our apps and seeing what is going on beneath the hood. Once a Log Tag has been defined in the code, we can then create a filter for it so that we see only the messages we are interested in. The Log class contains several methods to report information based on its level of importance. We used Log.d, which stands for debug. All these methods work with the same two parameters: Log.[method](String tag, String message). The full list of these methods is as follows: Log.v: Verbose Log.d: Debug Log.i: Information Log.w: Warning Log.e: Error Log.wtf: Unexpected error It is worth noting that most debug messages will be ignored during the packaging for distribution except for the verbose messages; thus, it is essential to remove them before your final build. Having seen a little more of the inner workings of our gesture detector and listener, we can now strip our code of unused methods by implementing GestureDetector.SimpleOnGestureListener. Implementing a SimpleOnGestureListener It is very simple to convert our gesture detector from one class of listener to another. All we need to do is change the class declaration and delete the unwanted methods. To do this, perform the following steps: Open the DetailActivity file. Change the class declaration for our gesture detector class to the following: class GalleryGestureDetector extends GestureDetector.SimpleOnGestureListener { Delete the onShowPress(), onSingleTapUp(), onScroll(), and onLongPress() methods. This is all you need to do to switch to the SimpleOnGestureListener. We have now successfully constructed and edited a gesture detector to allow the user to browse a series of images. You will have noticed that there is no onDoubleTap() method in the gesture listener. Double-taps can, in fact, be handled with the third GestureDetector listener, OnDoubleTapListener, which operates in a very similar way to the other two. However, Google, in its UI guidelines, recommends that a long press should be used instead, whenever possible. Before moving on to multitouch events, we will take a look at how to attach a GestureDetector listener to an entire Activity by adding a splash screen to our project. In the process, we will also see how to create a Full-Screen Activity and how to edit the Maniftest file so that our app launches with the splash screen. Adding a GestureDetector to an Activity The method we have employed so far allows us to attach a GestureDetector listener to any view or views and this, of course, applies to ViewGroups such as Layouts. There are times when we may want to detect gestures to be applied to the whole screen. For this purpose, we will create a splash screen that can be dismissed with a long press. There are two things we need to do before implementing the gesture detector: creating a layout and editing the Manifest file so that the app launches with our splash screen. Designing the splash screen layout The main difference between processing gestures for a whole Activity and an individual widget, is that we do not need an OnTouchListener as we can override the Activity's own onTouchEvent(). Here is how it is done: Create a new Blank Activity from the Project Explorer context menu called SplashActivity.java. The Activity wizard should have created an associated XML layout called activity_splash.xml. Open this and view it using the Text tab. Remove all the padding properties from the root layout so that it looks similar to this: <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.kyle.ancientbritain .SplashActivity"> Here we will need an image to act as the background for our splash screen. If you have not downloaded the project files from the Packt website, find an image, roughly of the size and aspect of your target device's screen, upload it to the project drawable folder, and call it splash. The file I used is 480 x 800 px. Remove the TextView that the wizard placed inside the layout and replace it with this ImageView: <ImageView android:id="@+id/splash_image" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/splash"/> Create a TextView beneath this, such as the following: <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" android:layout_marginBottom="40dp" android:gravity="center_horizontal" android:textAppearance="?android:attr/ textAppearanceLarge" android:textColor="#fffcfcbd"/> Add the following text property: android:text="Welcome to <b>Ancient Britain</b>npress and hold nanywhere on the screennto start" To save time adding string resources to the strings.xml file, enter a hardcoded string such as the preceding one and heed the warning from the editor to have the string extracted for you like this: There is nothing in this layout that we have not encountered before. We removed all the padding so that our splash image will fill the layout; however, you will see from the preview that this does not appear to be the case. We will deal with this next in our Java code, but we need to edit our Manifest first so that the app gets launched with our SplashActivity. Editing the Manifest It is very simple to configure the AndroidManifest file so that an app will get launched with whichever Activity we choose; the way it does so is with an intent. While we are editing the Manifest, we will also configure the display to fill the screen. Simply follow these steps: Open the res/values-v21/styles.xml file and add the following style: <style name="SplashTheme" parent="android:Theme.Material. NoActionBar.Fullscreen"> </style> Open the AndroidManifest.xml file. Cut-and-paste the <intent-filter> element from MainActivity to SplashActivity. Include the following properties so that the entire <activity> node looks similar to this: <activity android:name=".SplashActivity" android:theme="@style/SplashTheme" android:screenOrientation="portrait" android:configChanges="orientation|screenSize" android:label="Old UK" > <intent-filter> <action android_name="android.intent.action.MAIN" /> <category android_name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> We have encountered themes and styles before and, here, we took advantage of a built-in theme designed for full screen activities. In many cases, we might have designed a landscape layout here but, as is often the case with splash screens, we locked the orientation with the android:screenOrientation property. The android:configChanges line is not actually needed here, but is included as it is useful to know about it. Configuring any attribute such as this prevents the system from automatically reloading the Activity whenever the device is rotated or the screen size changed. Instead of the Activity restarting, the onConfigurationChanged() method is called. This was not needed here as the screen size and orientation were taken care of in the previous lines of code and this line was only included as a point of interest. Finally, we changed the value of android:label. You may have noticed that, depending on the screen size of the device you are using, the name of our app is not displayed in full on the home screen or apps drawer. In such cases, when you want to use a shortened name for your app, it can be inserted here. With everything else in place, we can get on with adding our gesture detector. This is not dissimilar to the way we did this before but, this time, we will apply the detector to the whole screen and will be listening for a long press, rather than a fling. Adding the GestureDetector Along with implementing a gesture detector for the entire Activity here, we will also take the final step in configuring our splash screen so that the image fills the screen, but maintains its aspect ratio. Follow these steps to complete the app splash screen. Open the SplashActivity file. Declare a GestureDetector as we did in the earlier exercise: private GestureDetector detector; In the onCreate() method, assign and configure our splash image and gesture detector like this: ImageView imageView = (ImageView) findViewById(R.id.splash_image); imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); detector = new GestureDetector(this, new SplashListener()); Now, override the Activity's onTouchEvent() like this: @Override public boolean onTouchEvent(MotionEvent event) { this.detector.onTouchEvent(event); return super.onTouchEvent(event); } Create the following SimpleOnGestureListener class: private class SplashListener extends GestureDetector. SimpleOnGestureListener { @Override public boolean onDown(MotionEvent e) { return true; } @Override public void onLongPress(MotionEvent e) { startActivity(new Intent(getApplicationContext(), MainActivity.class)); } } Build and run the app on your phone or an emulator. The way a gesture detector is implemented across an entire Activity should be familiar by this point, as should the capturing of the long press event. The ImageView.setScaleType(ImageView.ScaleType) method is essential here; it is a very useful method in general. The CENTER_CROP constant scales the image to fill the view while maintaining the aspect ratio, cropping the edges when necessary. There are several similar ScaleTypes, such as CENTER_INSIDE, which scales the image to the maximum size possible without cropping it, and CENTER, which does not scale the image at all. The beauty of CENTER_CROP is that it means that we don't have to design a separate image for every possible aspect ratio on the numerous devices our apps will end up running on. Provided that we make allowances for very wide or very narrow screens by not including essential information too close to the edges, we only need to provide a handful of images of varying pixel densities to maintain the image quality on large, high-resolution devices. The scale type of ImageView can be set from within XML with android:scaleType="centerCrop", for example. You may have wondered why we did not use the built-in Full-Screen Activity from the wizard; we could easily have done so. The template code the wizard creates for a Full-Screen Activity provides far more features than we needed for this exercise. Nevertheless, the template is worth taking a look at, especially if you want a fullscreen that brings the status bar and other components into view when the user interacts with the Activity. That brings us to the end of this article. Not only have we seen how to make our apps interact with touch events and gestures, but also how to send debug messages to the IDE and make a Full-Screen Activity. Summary We began this article by adding a GestureDetector to our project. We then edited it so that we could filter out meaningful touch events (swipe right and left, in this case). We went on to see how the SimpleOnGestureListener can save us a lot of time when we are only interested in catching a subset of the recognized gestures. We also saw how to use DDMS to pass debug messages during runtime and how, through a combination of XML and Java, the status and action bars can be hidden and the entire screen be filled with a single view or view group. Resources for Article: Further resources on this subject: Speeding up Gradle builds for Android [Article] Saying Hello to Unity and Android [Article] Testing with the Android SDK [Article]
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article-image-rundown-example
Packt
06 Aug 2015
10 min read
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Rundown Example

Packt
06 Aug 2015
10 min read
In this article by Miguel Oliveira, author of the book Microsoft System Center Orchestrator 2012 R2 Essentials, we will learn to get started on the creational process. We will be able to driven on how to address and connect all the pieces together in order to successfully create a Runbook. (For more resources related to this topic, see here.) Runbook for Active Directory User Account Provisioning Now, for this Runbook, we've been challenged by our HR department to come out with a solution for them to be able to create new user accounts for recently joined employees. The request was specifically drawn with the target for them (HR) to be able to: Provide the first and last name Provide the department name Get that user added to the proper department group and get all the information of the user Send the newly created account to the IT department to provide a machine, a phone, and an e-mail address With these requirements at the back of our heads, let's see which activities we need to get into our Runbook. I'll place these in steps for this example, so it's easy to follow: Data input: So, we definitely need an activity to allow the HR to feed the information into the Runbook. For this, we can use the Initialize Data activity (Runbook control category), or we could work along with a monitored file and read the data from a line, or even from a SharePoint list. But to keep it simple for now, let's use the Initialize Data. Data processing: In here, the idea would be to retrieve the Department given by the HR and process it to retrieve the group (the Get Group activity from the Active Directory category) and include our user (the Add User To Group activity from the Active Directory category) into the group we've retrieved; but in between, we'll need to create the user account (Create User activity from the Active Directory category), and generate a password (the Generate Random Text activity from the Utilities category). Data output: At the very end of all this, send an e-mail (the Send Email activity from the Email category) back to HR with the account information and status of its creation and inform our IT department (for security reasons) too about the account that has been created. We're also going to closely watch for errors with a few activities that will show us whether an error occurs. Let's see the look of this Runbook from a structured point (and actually almost how it's going to look in the end) and we'll detail the activities and options within them step by step from there. Here's the aspect of the Runbook structured with the activities properly linked between them allowing the data bus to flow and transport the published data from the beginning to the end: As described in the steps, we start with an Initialize Data activity in which we're going to request some inputs from the person executing the Runbook. To create a user, we'll need his First Name and Last Name and also the Department. For that, we'll fill in the following information in the Fetch User Details activity seen in the previous screenshot. For the sake of avoiding errors, the HR department should have a proper list of departments that we know will translate into a proper group in the upcoming activities. After filling the information, the processing of the information begins and with it, our automation process that will find the group for that department, create our user account, set a password, change password on the first login, add the user to the group, and enable the account. For that, we'll start with the Get Group activity in which we'll fill in the following: Set up the proper configuration in the Get Group Properties window for the Active Directory Domain in which you'll want this to execute, and in the Filters options, set to filter Sam Account Name of the group as the Department filled by the HR department. Now we'll set another prerequisite to create the account—the password! For this, we'll get the Generate Random Text activity and set it with the following parameters: These values should be set to accordingly accommodate your existing security policy and minimum password requirements for your domain. These previous activities are all we need to have the necessary values to proceed with the account creation by using the Create User activity. These should be the parameters filled in. All of these parameters are actually being retrieved from the Published Data from the last activities. As the list is long, we'll detail them here for your better understanding. Everything that's between {} is Published Data: Common Name: {First Name from "Fetch User Details"} {Last Name from "Fetch User Details"} Department: {Display Name from "Get Group"} Display Name: {First Name from "Fetch User Details"} {Last Name from "Fetch User Details"} First Name: {First Name from "Fetch User Details"} Last Name: {Last Name from "Fetch User Details"} Password: {Random text from "Generate Random Text"} User Must Change Password: True SAM Account Name: {First Name from "Fetch User Details"}.{Last Name from "Fetch User Details"} User Principal Name: {First Name from "Fetch User Details"}.{Last Name from "Fetch User Details"}@test.local Email: {First Name from "Fetch User Details"}.{Last Name from "Fetch User Details"}@test.com Manager: {Managed By from "Get Group"} As said previously, most of the data comes from the Published Data and we've created subscriptions in all these fields to retrieve it. The only two fields that have data different from Published Data are the User Must Change Password, User Principal Name (UPN), and Email. The User Must Change Password is a Boolean field that will display only Yes or No, and in the UPN and e-mail we've added the domain information (@test.local and @test.com) to the Published Data. Depending on the Create User activity's output, it will trigger a different activity. For now, let's assume that the activity returns a success on the execution, this will make the Runbook follow the smart link that goes on with the Get User activity. The Get User activity will retrieve all the information concerning the newly created user account that will be useful for the next activities down the line. In order to retrieve the proper information, we'll need to configure the following in the Filters area within the activity: You'll need to add a filter, selecting Sam Account Name and Relation as Equals for Value under the subscribed data from Sam Account Name that comes out of the Create User activity. From here, we'll link with the activity that Add User to Group (here renamed to Add User to Department) and within that activity we're going to specify the group and the user so the activity can add the user into the group. It should look exactly like the screenshot that follows: We'll once again assume that everything's running as expected and prepare our next activity that is to enable user account and for this one, we'll use the Enable User activity. The configuration of the activity can be seen in the next screenshot: Once again, we'll get the information out of the Published Data and feed it into the activity. After this activity is completed, we're going to log the execution and information output into the platform with the Send Platform Event activity so we can see any necessary information available from the execution. Here is a sample of the configuration for the message output: To get the Details text box expanded this way, right-click on it and select Expand… from the menu, then you can format and include the data that you feel is more important for you to see it. Then we'll send an e-mail for the HR team with the account creation details so they can communicate to the newly arrived employee and another e-mail for the IT department only with the account name and the department (plus the group name) for security reasons. Here are the samples of these two activities, starting with the HR e-mail: Let's go point by point on this configuration sample. In the Details section, we've settled the following: Subject: Account {Sam Account Name from "Get User"} Created Recipients: to: hr.dept@test.com Message: The message description is given in the following screenshot: Message option that consists of choosing the Priority of the message (high, normal, or low), and set the necessary SMTP authentication parameters (account, password, and domain) so you can send the message through your e-mail service. If you have an application e-mail service relay, you can leave the SMTP authentication without any configuration. In connect Connect option, you'll find the place to configure the e-mail address that you want the user to see and the SMTP connection (server, port, and SSL) through which you'll send your messages. Now our Send Email IT activity will be more or less the same, with the exception for the destination and the message itself. It should be something a little more or less like the following screenshot: By now you've got the idea and you're pumped to create new Runbooks, but we still have to do some error control on some of these tasks; although they're chained, if one fails, everything fails. So for this Runbook, we'll create error control on two tasks that if we observe well, are more or less the only two that can fail! One is the Create User Account activity, which can fail due to the user account existing or by some issue with privileges on its creation. The other is Add User To Department that might fail to add the user into the group for some reason. So for this, we'll create two notification activities called Send Event and Log Message that we'll rename to User Account Error and Group Error respectively. If we look into the User Account Error activity, we'll set something more or less like the following screenshot: A quick explanation of the settings is as follows: Computer: This is the computer to which Windows Event Viewer we're going to write the event into. In this case, we'll concentrate over our Management Server, but you might have a logging server for this. Message: The message gets logged into the windows event viewer. Here, we can subscribe for the error data coming out of the last activity executed. Severity: This is usually an Error. You can set Information or Warning if you are deploying these activities to keep a track on each given step. So for our Group Error Properties the philosophy will be the same. Now that we are all set, we'll need to work our smart links so that they can direct the Runbook execution flow into the following activity depending on the previous activity output (success or error). In the end, your Runbook should look a little bit more like this: That's it for the Runbook for Active Directory User Account Provisioning. We'll now speed up a little bit more on the other Runbooks as you'll have a much clearer understanding after this first sample. Summary We've seen one of the Runbook samples these Runbooks should serve as the base for real case scenarios in the environment and help us in the creativity process and also to better understand the configurations necessary on each activity in order to proceed successfully. Resources for Article: Further resources on this subject: Unpacking System Center 2012 Orchestrator [article] Working with VMware Infrastructure [article] Unboxing Docker [article]
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Cody A.
06 Aug 2015
8 min read
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Simplify Deployment with an Infrastructure Manifest, Part 2

Cody A.
06 Aug 2015
8 min read
This is the second part of a post on using a Manifest of your infrastructure for automation. The first part described how to use your Cloud API to transform Application Definitions into an Infrastructure Manifest. This post will show examples of automation tools built using an Infrastructure Manifest. In particular, we'll explore application deployment and load balancer configuration management. Recall our example Infrastructure Manifest from Part 1: { "prod": { "us-east-1": { "appserve01ea1": { "applications": [ "appserve" ], "zone": "us-east-1a", "fqdn": "ec2-1-2-3-4.compute-1.amazonaws.com", "private ip": "10.9.8.7", "public ip": "1.2.3.4", "id": "i-a1234bc5" }, ... }, ... } As I mentioned previously, this Manifest can form the basis for numerous automations. Some tools my team at Signal has built on top of this concept are automated deployments, load balancing, security group management, and DNS. Application Deployment Let's see how an Infrastructure Manifest can simplify application deployment. Although we'll use Fabric as the basis for our deployment system, the concept should work with Chef and many other push-based deployment systems as well. from json import load as json_decode from urllib2 import urlopen MANIFEST = json_decode(urlopen(env.manifest)) for hostname, meta in MANIFEST.iteritems(): for role in meta['roles']: env.roledefs[role].append(hostname) Note: For this to work, you must set the manifest URL in Fabric's environment as env.manifest. For example, you can set this in the ~/.fabricrc file or pass it on the command-line. manifest=http://manifest:5000/api/prod/us-east-1/manifest That's all Fabric really requires to know where to deploy each application! Given the manifest above, this would add the "appserve" role so that you can run tasks on these instances simultaneously. For example, to deploy the "appserve" application to all the hosts with this role: @task @roles('appserve') def deploy_appserve(): # standard Fabric deploy logic here Now calling fab deploy_appserve will run the commands to deploy the "appserve application on each host with the "appserve" role. Easy, right? You might want to deploy some applications to every host in your infrastructure. Instead of adding these special roles to every Application Definition, you can include them here. For example, if you have a custom monitoring application ("mymon"), then you can read the list of all hosts from the Manifest and add them to the "mymon" role. # set up special cases for roledefs: env.roledefs = defaultdict(list, { 'mymon': list(MANIFEST.keys()), }) Now, after adding a deploy_mymon task, you'll be able to easily deploy "mymon" to all hosts in your infrastructure. Even if you auto-deploy using a specialized git receiver, Jenkins hooks, or similar, this approach will enable you to make your deployments cloud-aware, to deploy each application to the appropriate hosts in your cloud. That's it! Deployments can't be much simpler than this. Load Balancer Configuration Management A common challenge in cloud environments is maintaining the list of all hosts for load balancer configurations. If you don't want to lock in to a vendor or cloud-specific solution such as Amazon ELB, you may choose an open source software load balancer such as HAProxy. However, this leaves you with the challenge of maintaining the configurations as hosts appear and disappear in your cloud-based infrastructure. This problem is amplified when you use software-based load balancers between each set of services (or each tier) in your application. Using the Infrastructure Manifest, a first-pass solution can be quite simple. You can revision-control the configuration templates and interpolate the application ports and host information from the Manifest. Then periodically update the generated configuration files and distribute them using your existing configuration management software (such as Puppet or Chef). Let's say you want to generate a HAProxy configuration for your load balancer. The complete configuration file might look like this: global user haproxy group haproxy daemon frontend main_vip bind *:80 # ACLs for basic name-based virtual-hosts acl appserve_host hdr_beg(host) -i app.example.com acl uiserve_host hdr_beg(host) -i portal.example.com use_backend appserve if appserve_host use_backend uiserve if uiserve_host default_backend uiserve backend appserve balance roundrobin option httpclose option httpchk GET /hc http-check disable-on-404 server appserve01ea1 10.42.1.91:8080 check server appserve02ea1 10.42.1.92:8080 check server appserve03ea1 10.42.1.93:8080 check backend uiserve balance roundrobin option httpclose option httpchk GET /hc server uiserve01ea1 10.42.1.111:8082 check server uiserve02ea1 10.42.1.112:8082 check The simplest way to produce this configuration file is to generate it from a template. There are many templating solutions from which to choose. I'm fond of Jinja2, so we'll use that for exploring this solution in Python. We want to load the template from a file located in a "templates" directory, so we start by creating a Jinja2 loader and environment: from jinja2 import Environment, FileSystemLoader import os loader = FileSystemLoader(os.path.join(os.path.dirname(__file__), 'templates')) environment = Environment(loader=loader, lstrip_blocks=True) The template corresponding to this output could look like this. We'll call it 'lb.txt' since it's for the lb server group. global user haproxy group haproxy daemon frontend main_vip bind *:80 # ACLs for basic name-based virtual-hosts acl appserve_host hdr_beg(host) -i app.example.com acl uiserve_host hdr_beg(host) -i portal.example.com use_backend appserve if appserve_host use_backend uiserve if uiserve_host default_backend uiserve backend appserve balance roundrobin option httpclose option httpchk GET {{ vips.appserve.healthcheck_resource }} http-check disable-on-404 {%- for server in vips.appserve.servers %} server {{ server['name'] }} {{ server.details['private_ip'] }}:{{ vips.appserve.backend_port }} check {%- endfor %} backend uiserve balance roundrobin option httpclose option httpchk GET {{ vips.uiserve.healthcheck_resource }} {%- for server in vips.uiserve.servers %} server {{ server['name'] }} {{ server.details['private_ip'] }}:{{ vips.uiserve.backend_port }} check {%- endfor %} You can see by examining the template that it only expects a single variable: vips. This is a map of application names to their load balancer configuration. Specifically, each vip contains a backend port, a healthcheck resource (i.e., HTTP path), and a list of servers (with server name and private IP address for each). Coincidentally, all of this information is available in the Infrastructure Manifest and Application Definitions we developed in Part 1. We can easily fetch this information from the webapp. from requests import get def main(manifest_host, env, region, server_group): manifest = get('http://%s/api/%s/%s/manifest' % (manifest_host, env, region)).json() applications = get('http://%s/api/applications' % manifest_host).json() print generate_haproxy(manifest, applications, server_group) Note: we didn't actually add the /api/applications endpoint last week, so its left as an exercise for the reader; hint: jsonify(config()['APPLICATIONS']). Now we can dive into the meat of this tool, the generate_haproxy function. As you might guess, this uses the Jinja2 environment to render the template. But first it must merge the Application Definitions and Manifest into the vips variable that the template expects. def generate_haproxy(manifest, applications, server_group): apps = {} for application, meta in applications.iteritems(): app_object = { 'servers': [], 'frontend_port': meta['frontend'], 'backend_port': meta['backend'], 'healthcheck_resource': meta['healthcheck']['resource'] } for server in manifest: if application in manifest[server]['applications']: app_object['servers'].append({'name': server, 'details': manifest[server]}) app_object['servers'].sort(key=lambda e: e['name']) apps[application] = app_object return environment.get_template("%s.txt" % server_group).render(vips=apps) There's not much going on here. We iterate through all the applications and create a vip (app_object) with all the needed variables for each one. Then we render the server_group's template with Jinja2. Finally, we can call the main we created above to see this in action: main('localhost:5000', 'prod', 'us-east-1', 'lb') This will print the HAProxy configuration for the lb load balancer group for your production us-east-1 region. (It assumes that the Manifest webapp is running on the same host.) Depending on what hosts you have in your cloud infrastructure, this should print something like the complete HAProxy configuration file shown at the top. To easily keep your load balancer configurations up-to-date, you could run this regularly for each environment and region. Then the generated files could be distributed using your existing configuration management system. Alternatively, if your load balancers support programmatic rule updates, that would be even cleaner than this simple first-pass approach which relies on configuration file updates. I hope this spurs your imagination and shows the benefit of using an Infrastructure Manifest to automate all the things. About the author Cody A. Ray is an inquisitive, tech-savvy, entrepreneurially-spirited dude. Currently, he is a software engineer at Signal, an amazing startup in downtown Chicago, where he gets to work with a dream team that's changing the service model underlying the Internet.
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