Software Architecture with C# 9 and .NET 5 - Second Edition

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By Gabriel Baptista , Francesco Abbruzzese
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    Understanding the Importance of Software Architecture
About this book

Software architecture is the practice of implementing structures and systems that streamline the software development process and improve the quality of an app. This fully revised and expanded second edition, featuring the latest features of .NET 5 and C# 9, enables you to acquire the key skills, knowledge, and best practices required to become an effective software architect.

This second edition features additional explanation of the principles of Software architecture, including new chapters on Azure Service Fabric, Kubernetes, and Blazor. It also includes more discussion on security, microservices, and DevOps, including GitHub deployments for the software development cycle.

You will begin by understanding how to transform user requirements into architectural needs and exploring the differences between functional and non-functional requirements. Next, you will explore how to carefully choose a cloud solution for your infrastructure, along with the factors that will help you manage your app in a cloud-based environment.

Finally, you will discover software design patterns and various software approaches that will allow you to solve common problems faced during development.

By the end of this book, you will be able to build and deliver highly scalable enterprise-ready apps that meet your organization’s business requirements.

Publication date:
December 2020


Understanding the Importance of Software Architecture

Software architecture is one of the most discussed topics in the software industry today, and its importance will certainly grow more in the future. The more we build complex and fantastic solutions, the more we need great software architectures to maintain them. But the speed at which new features are added to these software solutions keeps increasing, and new architectural opportunities keep emerging. That is the reason why you decided to read this book; it's the reason why we decided to write its second edition.

It's not a simple task to write about this important topic, which offers so many alternative techniques and solutions. The main objective of this book is not to build an exhaustive and never-ending list of available techniques and solutions, but to show how various families of techniques are related, and how they impact, in practice, the construction of a maintainable and sustainable solution.

The need to keep our focus on creating actual, effective enterprise solutions keeps increasing; users always need more new features in their applications. Moreover, the need to deliver frequent application versions (due to a quickly changing market) increases our obligation to have sophisticated software architecture and development techniques.

The following topics will be covered in this chapter:

  • The understanding of what software architecture is
  • Some software development process models that may help you as a software architect
  • The process for gathering the right information to design high-quality software
  • Design techniques for helping in the process of development
  • Cases where the requirements impact the system results
  • An introduction to the case study of the book

The case study of this book will take you through the process of creating the software architecture for a travel agency called World Wild Travel Club (WWTravelClub). The purpose of this case study is to help you understand the theory explained in each chapter, and to provide an example of how to develop an enterprise application with Azure, Azure DevOps, C# 9, .NET 5, ASP.NET, and other technologies that will be introduced in this book.

By the end of this chapter, you will be able to understand exactly what the mission of software architecture is. You will also learn what Azure is, and how to create your account on the platform. You'll also get an overview of software processes, models, and other techniques that will enable you to conduct your team.


What is software architecture?

If you are reading this book today, you should thank the computer scientists who decided to consider software development as an engineering area. This happened in the last century, more specifically, at the end of the sixties, when they proposed that the way we develop software is quite like the way we construct buildings. That is why we have the name software architecture. Like an architect designs a building and oversees its construction based on that design, the main goal of a software architect is to ensure that the software application is implemented well; and good implementation requires the design of a great solution.

In a professional development project, you must do the following things:

  • Define the customer requirements for the solution
  • Design a great solution to meet those requirements
  • Implement the designed solution
  • Validate the solution with your customer
  • Deliver the solution in the working environment

Software engineering defines these activities as the software development life cycle. All the theoretical software development process models (waterfall, spiral, incremental, agile, and so on) are somehow related to this cycle. No matter which model you use, if you do not work with the essential tasks presented earlier during your project, you will not deliver acceptable software as a solution.

The main point about designing great solutions is foundational to the purpose of this book. You must understand that great real-world solutions bring with them a few fundamental constraints:

  • The solution needs to meet user requirements
  • The solution needs to be delivered on time
  • The solution needs to adhere to the project budget
  • The solution needs to deliver good quality
  • The solution needs to guarantee safe and effective future evolution

Great solutions need to be sustainable, and you must understand that there is no sustainable software without great software architecture. Nowadays, great software architectures depend on both modern tools and modern environments to perfectly fit users' requirements.

For this reason, this book will use some great tools provided by Microsoft. The company has announced .NET 5 as a unified platform for software development, which gives us a great opportunity to create fantastic solutions.

Introducing .NET 5 | .NET Blog

Figure 1.1: .NET 5 platform

NET 5 is delivered together with C# 9. Considering the .NET approach of targeting so many platforms and devices, C# is now one of the most used programming languages in the world and runs on small devices up to huge servers in different operating systems and environments.

The book will also use Azure, which is Microsoft's cloud platform, where you will find all the components the company provides to build advanced software architecture solutions. One of them is Azure DevOps, an application life cycle management environment where you can build solutions using the latest approach for developing software.

Being a software architect means understanding the aforementioned technologies, and a lot of others, too. This book will guide you on a journey where, as a software architect working in a team, you will provide optimal solutions with the tools listed. Let us start this journey by creating your Azure account.

Creating an Azure account

Microsoft Azure is one of the best cloud solutions currently available on the market. It is important to know that, inside Azure, we will find a selection of components that can help us define the architecture of twenty-first-century solutions.

If you want to check the variety of components Microsoft Azure has, just check this incredible website developed by Alexey Polkovnikov:

This subsection will guide you in creating an Azure account. If you already have one, you can skip this part.

Start your access into Azure using the website address There, you will find the information you need to start your subscription. Translation to your native language is usually set automatically.

  1. Once you have accessed this portal, it is possible to sign up. If you have never done this before, it is possible to Start free, so you will be able to use some Azure features without spending any money. Please check the options for free plans at
  2. The process for creating a free account is quite simple, and you will be guided by a form that requires you to have a Microsoft Account or GitHub Account.
  3. During the process you will also be asked for a credit card number, to verify your identity and to keep out spam and bots. However, you will not be charged unless you upgrade the account.
  4. To finish the assignment, you will need to accept the subscription agreement, offer details, and privacy statement.

Once you finish the form, you will be able to access the Azure portal. As you can see in the following screenshot, the panel shows a dashboard that you can customize, and a menu on the left, where you can set up the Azure components you are going to use in your solution. Throughout this book, we will come back to this screenshot to set up the components to help us create modern software architecture. To find the next page, just select the left-menu icon (hamburger menu) and click on All services.

Figure 1.2: The Azure portal

Once you have your Azure account created, you are ready to understand how a software architect can conduct a team to develop software, taking advantage of all the opportunities offered by Azure. However, it is important to keep in mind that a software architect needs to go beyond technologies because this role is played by people who are expected to define how the software will be delivered.

Today, a software architect not only architects the basis of a software, but also determines how the whole software development and deployment process is conducted. The next topic will cover some of the most widely used software development paradigms the world over. We'll start by describing what the community refers to as traditional software engineering. After that, we'll cover the agile models that have changed the way we build software nowadays.


Software development process models

As a software architect, it's important for you to understand some of the common development processes that are currently used in most enterprises. A software development process defines how people in a team produce and deliver software. In general, this process relates to a software engineering theory, called a software development process model. From the time software development was defined as an engineering process, many process models for developing software have been proposed. Let us review the traditional software models, and then look at the agile ones that are currently common.

Reviewing traditional software development process models

Some of the models introduced in the software engineering theory are already considered traditional and quite obsolete. This book does not aim to cover all of them, but here, we will give a brief explanation of the ones that are still used in some companies – waterfall and incremental models.

Understanding the waterfall model principles

This topic may appear strange in a software architecture book from 2020, but yes, you may still find companies where the most traditional software process model remains the guideline for software development. This process executes all fundamental tasks in sequence. Any software development project consists of the following steps:

  • Requirements, where a product requirement document is created, and it is the basis for the software development
  • Design, where the software architecture is developed according to requirements
  • Implementation, where the software is programmed
  • Verification, where tests are taken in the application
  • Maintenance, where the cycle starts again, after a delivery

Let us look at a diagrammatic representation of this:

Figure 1.3: The waterfall development cycle (

Often, the use of waterfall models causes problems related to delays in the delivery of a functional version of the software, and user dissatisfaction due to the distance between expectations and the final product delivered. Besides, in my experience, having application tests start only after the completion of development always feels terribly stressful.

Analyzing the incremental model

Incremental development is an approach that tries to overcome the biggest problem of the waterfall model: the user can test the solution only at the end of the project. The idea of this model is to give the users opportunities to interact with the solution as early as possible so that they can give useful feedback, which will help during the development of the software.

Figure 1.4: The incremental development cycle (

The incremental model presented in the preceding picture was introduced as an alternative to the waterfall approach. The idea of the model is to run for each increment a set of practices related to software development (Communication, Planning, Modeling, Construction, and Deployment). Although it mitigated the problems related to the lack of communication with the customer, for big projects, fewer increments were still a problem because the increments remained too long.

When the incremental approach was used on a large scale—mainly at the end of the last century—many problems related to project bureaucracy were reported, due to the large amount of documentation required. This clunky scenario caused the rise of a very important movement in the software development industry – agile.

Understanding agile software development process models

At the beginning of this century, developing software was considered one of the most chaotic activities in engineering. The percentage of software projects that failed was incredibly high, and this fact proved the need for a different approach to deal with the flexibility required by software development projects.

In 2001, the Agile Manifesto was introduced to the world, and from that time forward various agile process models were proposed. Some of them have survived up until now and are still very common.

The Agile Manifesto is translated into more than 60 languages. Please check out its link at

One of the biggest differences between agile models and traditional models is the way developers interact with the customer. The message that all agile models transmit is that the faster you deliver software to the user, the better. This idea is sometimes confusing for software developers who understand this as – let's try coding, and that's all, folks!

However, there is an important observation of the Agile Manifesto that many people do not read when they start working with agile:

Figure 1.5: Manifesto for Agile software development

A software architect always needs to remember this. Agile processes do not mean a lack of discipline. Moreover, when you use the agile process, you'll quickly understand that there is no way to develop good software without discipline. On the other hand, as a software architect, you need to understand that soft means flexibility. A software project that refuses to be flexible tends to ruin itself over time.

The 12 principles behind agile are foundational to this flexible approach:

  1. Continuously delivering valuable software to satisfy the customer must be the highest priority of any developer.
  2. Changing requirements needs to be understood as an opportunity to make the customer more competitive.
  3. Do use a weekly timescale to deliver software.
  4. A software team must be composed of business people and developers.
  5. A software team needs to be trusted and should have the correct environment to get the project done.
  6. The best way to communicate with a software team is face to face.
  7. You can understand the greatest software team achievement as when the software is really working on production.
  8. Agile is working properly when it delivers sustainable development.
  9. The more you invest in techniques and good design, the more agile you are.
  10. Simplicity is essential.
  11. The more self-organized the teams are, the better-quality delivery you will have.
  12. Software teams tend to improve their behavior from time to time, analyzing and adjusting their process.

Even 20 years after the launch of the Agile Manifesto, its importance and connection to the current needs of software teams remain intact. Certainly, there are many companies where this approach is not well accepted, but as a software architect you should understand this as an opportunity to transform practices and evolve the team with you are working.

There are many techniques and models that were presented to the software community with the agile approach. The next subtopics will discuss Lean software development, Extreme Programming, and Scrum, so that you can decide, as a software architect, which ones you might use to improve your software delivery.

Lean software development

After the Agile Manifesto, the approach of Lean software development was introduced to the community as an adaptation of a well-known movement in automobile engineering; Toyota's model for building cars. The worldwide Lean manufacturing method delivers a high level of quality even with few resources.

Mary and Tom Poppendieck listed seven Lean principles for software development, really connected to agile and to the approach of many companies of this century. I've listed them here:

  1. Eliminate waste: You may consider waste to be anything that will interfere with the delivery of the real need of a customer.
  2. Build quality in: An organization that wants to guarantee quality needs to promote it in processes that build code from the beginning, instead of only consider it after code is being tested.
  3. Create knowledge: Companies that achieved excellence have a common pattern of generating new knowledge by disciplined experimentation, documenting it, and guaranteeing that this knowledge is spread all over the organization.
  4. Defer commitment: Plan decisions to its last chance before causing damage to the project.
  5. Deliver fast: The faster you deliver software, the more elimination of waste you have. Companies that compete using time frequency have significant advantages over their competitors.
  6. Respect people: Giving reasonable objectives to the team, together with plans that will guide them to self-organize their routine, is a matter of respecting people that you work with.
  7. Optimize the whole: A Lean company improves all the cycle of value; from the moment it receives a new requirement up to the one it delivers when the software is done.

The Lean principles cause a team or company approach to improve the quality of the features that the customer really needs. It also creates a reduction in time spent on features that will not be used by the time the software is delivered to the customer. In Lean, deciding the features that are important to the customer guides the team in delivering software that matters, and this is exactly what the Agile Manifesto intends to promote in software teams.

Extreme Programming

Just before the release of the Agile Manifesto, some of the participants who designed the document, especially Kent Beck, presented to the world the Extreme Programming (XP) methodology for developing software.

XP is based on values of simplicity, communication, feedback, respect, and courage. It was considered later as a social change in programming, according to Beck in his second book about the topic. It certainly promotes a huge change in the flow of development.

XP indicates that every team should have the simplicity to do only what it was asked for, communicating face to face daily, demonstrating the software early to get feedback, respecting the expertise of each member of the team, and having the courage to tell the truth about progress and estimates, considering the team's work as a whole.

XP also delivers a set of rules. These rules may be changed by the team if they detect something is not working properly, but it's important to always maintain the values of the methodology.

These rules are divided into planning, managing, designing, coding, and testing. Don Wells has mapped XP at the site Although some of the ideas of the methodology were criticized strongly by many companies and specialists, there are many good practices that are used today:

  • Writing software requirements using user stories: User stories are considered an agile approach to describe user needs, together with the acceptance tests that will be used to guarantee the correct implementation.
  • Divide software into iterations and deliver small releases: The practice of iterating in software development is defended by all methodologies after waterfall. The fact of delivering faster versions decreases the risks of not achieving the customer's expectations.
  • Avoid working overtime and guarantee a sustainable velocity: Although this must be one of the hardest tasks a software architect may deal with, overtime working indicates something is not working properly in the process.
  • Keep things simple: While developing solutions, it is quite common to try to anticipate features that the customer would like to have. This approach increases the complexity of the development and the time to market the solution. A different approach will cause high costs, and probably a low level of features that are actually used, in the system you are developing.
  • Refactoring: The approach of refactoring the code continuously is good because it enables the evolution of your software and guarantees the design improvement that will truly be necessary due to the normal technical changes of the platforms you use to develop.
  • Keep the customer always available: If you follow the rule from XP, you should have an expert customer inside your team. This is certainly something that is hard to get and deal with, but the main idea of this approach is guaranteeing that the customer is involved in all parts of development. As another bonus, having the customer close to your team means they understand the difficulties and expertise the team has, enabling an increase of the trust between the parties.
  • Continuous integration: This practice is one of the bases of the current DevOps approach. The less difference you have between your personal code repository and the main code repository, the better.
  • Code the unit test first: A unit test is an approach where you program specific code for testing a single unit (class/method) of your project. This is discussed in a current development methodology called Test-Driven Development (TDD). The main goal here is to guarantee that every business rule has its own unit test case.
  • Code must be written to agreed standards: The need of determining standards for coding is connected to the idea that no matter which developer you have working on a specific part of the project, the code must be written so that any of them will understand it.
  • Pair programming: Pair programming is another difficult approach to achieve in every single minute of a software project, but the technique itself—one programmer coding and the other actively observing and offering comments, criticism, and advice—is useful in critical scenarios.
  • Acceptance tests: The adoption of acceptance tests to meet user stories is a good way to guarantee that new released versions of the software do not cause damage to its current needs. An even better option is to have these acceptance tests automated.

It is worth mentioning that many of these rules are today considered vital practices in different software development methodologies, including DevOps and Scrum. We will discuss DevOps later in this book, in Chapter 20, Understanding DevOps Principles. Let's get into the Scrum model right now.

Getting into the Scrum model

Scrum is an agile model for the management of software development projects. The model comes from Lean principles and is one of the widely used approaches for developing software nowadays.

Please check this link for more information about the Scrum framework:

As you can see in the following figure, the basis of Scrum is that you have a flexible backlog of user requirements (Product Backlog) that needs to be discussed in each agile cycle, called a Sprint. The Sprint goal (Sprint Backlog) is determined by the Scrum Team, composed of the Product Owner, the Scrum Master, and the Development Team. The Product Owner is responsible for prioritizing what will be delivered in that Sprint. During the Sprint, this person will help the team to develop the required features. The person who leads the team in the Scrum process is called the Scrum Master. All the meetings and processes are conducted by this person.

Figure 1.6: The Scrum process

It is important to notice that the Scrum process does not discuss how the software needs to be implemented, nor which activities will be done. Again, you must remember the basis of software development, discussed at the beginning of this chapter; that means Scrum needs to be implemented together with a process model. DevOps is one of the approaches that may help you use a software development process model together with Scrum. Check Chapter 20, Understanding DevOps Principles, to understand it better.


Gathering the right information to design high-quality software

Fantastic! You just started a software development project. Now, it's time to use all your knowledge to deliver the best software you can. Your first question is probably – How do I start? Well, as a software architect, you're going to be the one to answer it. And you can be sure your answer is going to evolve with each software project you lead.

Defining a software development process is the first task. This is generally done during the project planning process, or might happen before it starts.

Another very important task is to gather the software requirements. No matter which software development process you decide to use, collecting real user needs is part of a difficult and continuous job. Of course, there are techniques to help you with this, and you can be sure that gathering requirements will help you to define important aspects of your software architecture.

These two tasks are considered by most experts in software development as the keys to success at the end of the development project journey. As a software architect, you need to enable them so that you can avoid as many problems as possible while guiding your team.

Understanding the requirements gathering process

There are many different ways to represent the requirements. The most traditional approach consists of you having to write a perfect specification before the beginning of the analysis. Agile methods suggest instead that you need to write user stories, as soon as you are ready to start a development cycle.

Remember: You do not write requirements just for the user; you write them for you and your team too.

The truth is, that no matter the approach you decide to adopt in your projects, you will have to follow some steps to gather requirements. This is what we call requirements engineering.

Figure 1.7: Requirements engineering process

During this process, you need to be sure that the solution is feasible. In some cases, the feasibility analysis is part of the project planning process too, and by the time you start the requirements elicitation, you will have the feasibility report already done. So, let us check the other parts of this process, which will give you a lot of important information for the software architecture.

Detecting exact user needs

There are a lot of ways to detect what exactly the user needs for a specific scenario. This process is known as elicitation. In general, this can be done using techniques that will help you to understand what we call user requirements. Here, you have a list of common techniques:

  • The power of imagination: If you are an expert in the area where you are providing solutions, you may use your own imagination to find new user requirements. Brainstorming can be conducted together so that a group of experts can define user needs.
  • Questionnaires: This tool is useful for detecting common and important requirements such as the number and kind of users, peak system usage, and the commonly used operating system (OS) and web browser.
  • Interviews: Interviewing the users helps you as an architect to detect user requirements that perhaps questionnaires and your imagination will not cover.
  • Observation: There is no better way to understand the daily routine of a user than being with them for a day.

As soon as you apply one or more of these techniques, you will have great and valuable information about the user's needs.

Remember: You can use these techniques in any situation where the real need is to gather requirements, no matter if it is for the whole system or for a single story.

At that moment, you will be able to start analyzing these user needs, and detecting the user and system requirements. Let's see how to do so in the next section.

Analyzing requirements

When you've detected the user needs, it's time to begin analyzing the requirements. To do so, you can use techniques such as the following:

  • Prototyping: Prototypes are fantastic to clarify and to materialize the system requirements. Today, we have many tools that can help you to mock interfaces. A nice open source tool is the Pencil Project. You will find further information about it at
  • Use cases: The Unified Modeling Language (UML) use case model is an option if you need detailed documentation. The model is composed of a detailed specification and a diagram. ArgoUML is another open source tool that can help you out with this. You can see the model created in Figure 1.8:

Figure 1.8: Use case diagram example

While you are analyzing the requirements of the system, you will be able to clarify exactly what the users' needs are. This is helpful when you're not sure about the real problem you need to solve, and is much better than just starting to program the system and hoping for the best. Time invested in requirements analysis is time invested in better code later.

Writing the specifications

After you finish the analysis, it's important to register it as a specification. The specification document can be written using traditional requirements, or user stories, which are commonly used in agile projects.

A requirements specification represents the technical contract between the user and the team. There are some basic rules that this document needs to follow:

  • All stakeholders need to understand exactly what is written in the technical contract, even if they are not technicians.
  • The document needs to be clear.
  • You need to classify each requirement.
  • Use simple future tense to represent each requirement:
    • Bad example: A common user registers himself.
    • Good example: A common user shall register himself.
  • Ambiguity and controversy need to be avoided.

Some additional information can help the team to understand the context of the project they are going to work on. Here are some tips about how to add useful information:

  • Write an introductory chapter to give a full idea of the solution.
  • Create a glossary to make understanding easier.
  • Describe the kind of user the solution will cover.
  • Write functional and non-functional requirements:
    • Functional requirements are quite simple to understand because they describe exactly what the software will do. On the other hand, non-functional requirements determine the restrictions related to the software, which means scalability, robustness, security, and performance. We will cover these aspects in the next section.
  • Attach documents that can help the user to understand rules.

If you decide to write user stories, a good tip to follow is to write short sentences representing each moment in the system with each user, as follows:

As <user>, I want <feature>, so that <reason>

This approach will explain exactly the reason why that feature will be implemented. It's also a good tool to help you analyze the stories that are most critical, and prioritize the success of the project. They can also be great for informing the automated acceptance tests that should be built.

Understanding the principles of scalability, robustness, security, and performance

Detecting requirements is a task that will let you understand the software you are going to develop. However, as a software architect, you have to pay attention to more than just the functional requirements for that system. Understanding the non-functional requirements is important, and one of the earliest activities for a software architect.

We are going to look at this in more detail in Chapter 2, Non-Functional Requirements, but at this point, it's important to know that the principles of scalability, robustness, security, and performance need to be applied for the requirements gathering process. Let us look at each concept:

  • Scalability: As a software developer, globalization gives you the opportunity to have your solution running all over the world. This is fantastic, but you, as a software architect, need to design a solution that provides that possibility. Scalability is the possibility for an application to increase its processing power as soon as it is necessary, due to the number of resources that are being consumed.
  • Robustness: No matter how scalable your application is, if it is not able to guarantee a stable and always-on solution, you are not going to get any peace. Robustness is important for critical solutions, where you do not have the opportunity for maintenance at any time due to the kind of problem that the application solves. In many industries, the software cannot stop, and lots of routines run when nobody is available (overnight, holidays, and so on). Designing a robust solution will give you the freedom to live while your software is running well.
  • Security: This is another really important area that needs to be discussed after the requirements stage. Everybody worries about security, and different laws dealing with it are in place and being proposed in different parts of the world. You, as a software architect, must understand that security needs to be provided by design. This is the only way to cope with all the needs that the security community is discussing right now.
  • Performance: The process of understanding the system you are going to develop will probably give you a good idea of what you'll need to do to get the desired performance from the system. This topic needs to be discussed with the user, to identify most of the bottlenecks you will face during the development stage.

It is worth mentioning that all these concepts are requirements for the new generation of solutions that the world needs. What differentiates good software from incredible software is the amount of work done to meet the project requirements.

Reviewing the specification

Once you have the specification written, it is time to confirm with the stakeholders whether they agree with it. This can be done in a review meeting, or can be done online using collaboration tools.

This is when you present all the prototypes, documents, and information you have gathered. As soon as everybody agrees with the specification, you are ready to start studying the best way to implement this part of your project.

It is worth mentioning that you might use the process described here for both the complete software or for a small part of it.


Using design techniques as a helpful tool

Defining a solution is not easy. Determining its technology increases the difficulty of doing so. It is true that, during your career as a software architect, you will find many projects where your customer will bring you a solution ready for development. This can get quite complicated if you consider that solution as the correct solution; most of the time, there will be architectural and functional mistakes that will cause problems in the solution in the future.

There are some cases where the problem is worse—when the customer does not know the best solution for the problem. Some design techniques can help us with this, and we will introduce two of them here: Design Thinking and Design Sprint.

What you must understand is that these techniques can be a fantastic option to discover real requirements. As a software architect, you are committed to helping your team to use the correct tools at the correct time, and these tools may be the right options to ensure the project's success.

Design Thinking

Design Thinking is a process that allows you to collect data directly from the users, focusing on achieving the best results to solve a problem. During this process, the team will have the opportunity to discover all personas that will interact with the system. This will have a wonderful impact on the solution since you can develop the software by focusing on the user experience, which can have a fantastic impact on the results.

The process is based on the following steps:

  • Empathize: In this step, you must execute field research to discover the users' concerns. This is where you find out about the users of the system. The process is good for making you understand why and for whom you are developing this software.
  • Define: Once you have the users' concerns, it is time to define their needs to solve them.
  • Ideate: The needs will provide an opportunity to brainstorm some possible solutions.
  • Prototype: These solutions can be developed as mock-ups to confirm whether they are good ones.
  • Test: Testing the prototypes will help you to understand the prototype that is most connected to the real needs of the users.

The focus of a technique like this one is to accelerate the process of detecting the right product, considering the minimum viable product (MVP). For sure, the prototype process will help stakeholders to understand the final product and, at the same time, engage the team to deliver the best solution.

Design Sprint

Design Sprint is a process focused on solving critical business questions through design in a five-day sprint. This technique was presented by Google, and it is an alternative that allows you to quickly test and learn from an idea, needing to build and launch a solution to market.

The process is based on a week dedicated by experts to solve the problem mentioned, in a war room prepared for that purpose. The week is separated like this:

  • Monday: The focus of this day is to identify the target of the sprint and map the challenge to achieve it.
  • Tuesday: After understanding the goal of the sprint, participants start sketching solutions that may solve it. It is time to find customers to test the new solution that will be provided.
  • Wednesday: This is when the team needs to decide the solutions that have the greatest chance to solve the problem. Besides, on Wednesday the team must draw these solutions into a storyboard, preparing a plan for the prototype.
  • Thursday: It is time to prototype the idea planned on the storyboard.
  • Friday: Having completed the prototype, the team presents it to customers, learning by getting information from their reaction to the solution designed.

As you can see in both techniques, the acceleration of collecting reactions from customers comes from prototypes that will materialize your team's ideas into something more tangible for the end-user.


Common cases where the requirements gathering process impacted system results

All the information discussed up to this point in the chapter is useful if you want to design software following the principles of good engineering. This discussion is not related to developing by using traditional or agile methods, but focuses on building software professionally or as an amateur.

It's also a good idea to know about some cases where failing to perform the activities you read about caused some trouble for the software project. The following cases intend to describe what could go wrong, and how the preceding techniques could have helped the development team to solve the problems.

In most cases, simple action could have guaranteed better communication between the team and the customer, and this easy communication flow would have transformed a big problem into a real solution. Let's examine three common cases where the requirements gathering impacted the results of performance, functionality, and usability.

Case 1 – my website is too slow to open that page!

Performance is one of the biggest problems that you as a software architect will deal with during your career. The reason why this aspect of any software is so problematic is that we do not have infinite computational resources to solve problems. Besides, the cost of computation is still high, especially if you are talking about software with a high number of simultaneous users.

You cannot solve performance problems by writing requirements. However, you will not end up in trouble if you write them correctly. The idea here is that requirements must present the desired performance of a system. A simple sentence, describing this, can help the entire team that works on the project:

Non-functional requirement: Performance – any web page of this software shall respond in at least 2 seconds, even when 1,000 users are accessing it concurrently.

The preceding sentence just makes everybody (users, testers, developers, architects, managers, and so on) sure that any web page has a target to achieve. This is a good start, but it's not enough. A great environment to both develop and deploy your application is also important. This is where .NET 5 can help you a lot; especially if you are talking about web apps, ASP.NET Core is considered one of the fastest options to deliver solutions today.

If you talk about performance, you, as a software architect, should consider the use of the techniques listed in the following sections together with specific tests to guarantee this non-functional requirement. It's also important to mention that ASP.NET Core will help you to use them easily, together with some Platform as a Service (PaaS) solutions delivered by Microsoft Azure.

Understanding caching

Caching is a great technique to avoid queries that can consume time and, in general, give the same result. For instance, if you are fetching the available car models in a database, the number of cars in the database can increase, but they will not change. Once you have an application that constantly accesses car models, a good practice is to cache that information.

It is important to understand that a cache is stored in the backend and that cache is shared by the whole application (in-memory caching). A point to focus on is that when you are working on a scalable solution, you can configure a distributed cache to solve it using the Azure platform. In fact, ASP.NET provides both, so you can decide on the one that bests fits your needs. Chapter 2, Non-Functional Requirements, covers scalability aspects in the Azure platform.

Applying asynchronous programming

When you develop ASP.NET applications, you need to keep in mind that your app needs to be designed for simultaneous access by many users. Asynchronous programming lets you do this simply, giving you the keywords async and await.

The basic concept behind these keywords is that async enables any method to run asynchronously. On the other hand, await lets you synchronize the call of an asynchronous method without blocking the thread that is calling it. This easy-to-develop pattern will make your application run without performance bottlenecks and better responsiveness. This book will cover more about this subject in Chapter 2, Non-Functional Requirements.

Dealing with object allocation

One very good tip to avoid a lack of performance is to understand how the Garbage Collector (GC) works. The GC is the engine that will free memory automatically when you finish using it. There are some very important aspects of this topic, due to the complexity that the GC has.

Some types of objects are not collected by the GC if you do not dispose of them. The list includes any object that interacts with I/O, such as files and streaming. If you do not correctly use the C# syntax to create and destroy this kind of object, you will have memory leaks, which will deteriorate your application performance.

The incorrect way of working with I/O objects is:

System.IO.StreamWriter file = new System.IO.StreamWriter(@"C:\sample.txt");
file.WriteLine("Just writing a simple line");

The correct way of working with I/O objects is:

using (System.IO.StreamWriter file = new System.IO.StreamWriter(@"C:\sample.txt"))
file.WriteLine("Just writing a simple line");

It might be worth noting that this correct approach also ensures the file gets written (it calls Flush). In the incorrect example, the contents might not even be written to the file. Even though the preceding practice is mandatory for I/O objects, it is totally recommended that you keep doing this in all disposable objects. Indeed, using code analyzers in your solutions with warnings as errors will prevent you from accidentally making these mistakes! This will help the GC and will keep your application running with the right amount of memory. Depending on the type of object, mistakes here can snowball, and you could end up with other bad things at scale, for instance, port/connection exhaustion.

Another important aspect that you need to know about is that the time spent by the GC to collect objects will interfere with the performance of your app. Because of this, avoid allocating large objects; otherwise, it can cause you trouble waiting for the GC to finish its task.

Getting better database access

One of the most common performance Achilles' heels is database access. The reason why this is still a big problem is the lack of attention while writing queries or lambda expressions to get information from the database. This book will cover Entity Framework Core in Chapter 8, Interacting with Data in C# – Entity Framework Core, but it is important to know what to choose and the correct data information to read from a database. Filtering columns and lines is imperative for an application that wants to deliver on performance.

The good thing is that best practices related to caching, asynchronous programming, and object allocation fit completely into the environment of databases. It's only a matter of choosing the correct pattern to get better-performance software.

Case 2 – the user's needs are not properly implemented

The more that technology is used in a wide variety of areas, the more difficult it is to deliver exactly what the user needs. Maybe this sentence sounds weird to you, but you must understand that developers, in general, study how to develop software, but they rarely study to deliver the needs of a specific area. Of course, it is not easy to learn how to develop software, but it is even more difficult to understand a specific need in a specific area. Software development nowadays delivers software to all possible types of industries. The question here is how can a developer, whether a software architect or not, evolve enough to deliver software in the area they are responsible for?

Gathering software requirements will help you in this tough task; writing them will make you understand and organize the architecture of the system. There are several ways to minimize the risks of implementing something different from what the user really needs:

  • Prototyping the interface to achieve an understanding of the user interface faster
  • Designing the data flow to detect gaps between the system and the user operation
  • Frequent meetings to be updated on the user's current needs and aligned to incremental deliveries

Again, as a software architect, you will have to define how the software will be implemented. Most of the time, you are not going to be the one who programs it, but you will always be the one responsible for this. For this reason, some techniques can be useful to avoid the wrong implementation:

  • Requirements are reviewed with the developers to guarantee that they understand what they need to develop.
  • Code inspection to validate a predefined code standard. We will cover this in Chapter 19, Using Tools to Write Better Code.
  • Meetings to eliminate impediments.

Remember, the implementation matching the user needs is your responsibility. Use every tool you can to meet it.

Case 3 – the usability of the system does not meet user needs

Usability is a key point for the success of a software project. The way the software is presented and how it solves a problem can help the user to decide whether they want to use it or not. As a software architect, you must keep in mind that delivering software with good usability is mandatory nowadays.

There are basic concepts of usability that this book does not intend to cover, but a good way to meet the correct user needs when it comes to usability is by understanding who is going to use the software. Design Thinking can help you a lot with that, as was discussed earlier in this chapter.

Understanding the user will help you to decide whether the software is going to run on a web page, or a cell phone, or even in the background. This understanding is very important to a software architect because the elements of a system will be better presented if you correctly map who will use them.

On the other hand, if you do not care about that, you will just deliver software that works. This can be good for a short time, but it will not exactly meet the real needs that made a person ask you to architect the software. You must keep in mind the options and understand that good software is designed to run on many platforms and devices.

You will be happy to know that .NET 5 is an incredible cross-platform option for that. So, you can develop solutions to run your apps in Linux, Windows, Android, and iOS. You can run your applications on big screens, tablets, cell phones, and even drones! You can embed apps on boards for automation or in HoloLens for mixed reality. Software architects must be open-minded to design exactly what their users need.


Case study – introducing World Wild Travel Club

As we mentioned at the beginning of this chapter, the case study of this book will take you on a journey of creating the software architecture for a travel agency called World Wild Travel Club (WWTravelClub).

WWTravelClub is a travel agency that was created to change the way people make decisions about their vacations and other trips around the world. To do so, they are developing an online service where every detail of a trip experience will be assisted by a club of experts specifically selected for each destination.

The concept of this platform is that you can be both a visitor and a destination expert at the same time. The more you participate as an expert in a destination, the higher the points you will score. These points can be exchanged for tickets that people buy online using the platform.

The customer came with the following requirements for the platform. It is important to know that, in general, customers do not bring the requirements ready for development. That is why the requirements gathering process is so important:

  • Common user view:
    • Promotional packages on the home page
    • Search for packages
    • Details for each package:
      • Buy a package
      • Buy a package with a club of experts included:
        • Comment on your experience
        • Ask an expert
        • Evaluate an expert
      • Register as a common user
  • Destination expert view:
    • The same view as the common user view
    • Answer the questions asking for your destination expertise
    • Manage the points you scored answering questions:
    • Exchange points for tickets
  • Administrator view:
    • Manage packages
    • Manage common users
    • Manage destination experts

To finish this, it is important to note that WWTravelClub intends to have more than 100 destination experts per package and will offer around 1,000 different packages all over the world.

Understanding user needs and system requirements

To summarize the user needs of WWTravelClub, you can read the following user stories:

  • US_001: As a common user, I want to view promotional packages on the home page, so that I can easily find my next vacation
  • US_002: As a common user, I want to search for packages I cannot find on the home page so that I can explore other trip opportunities
  • US_003: As a common user, I want to see the details of a package, so that I can decide which package to buy
  • US_004: As a common user, I want to register myself, so that I can start buying the package
  • US_005: As a registered user, I want to process the payment, so that I can buy a package
  • US_006: As a registered user, I want to buy a package with an expert recommendation included, so that I can have an exclusive trip experience
  • US_007: As a registered user, I want to ask for an expert, so that I find out the best things I can do on my trip
  • US_008: As a registered user, I want to comment on my experience, so that I can give feedback from my trip
  • US_009: As a registered user, I want to evaluate an expert who helps me, so that I can share with others how fantastic they were
  • US_010: As a registered user, I want to register as a destination expert view, so that I can help people who travel to my city
  • US_011: As an expert user, I want to answer questions about my city, so that I can score points to be exchanged in the future
  • US_012: As an expert user, I want to exchange points for tickets, so that I can travel around the world more
  • US_013: As an administrator user, I want to manage packages, so that users can have fantastic opportunities to travel
  • US_014: As an administrator user, I want to manage registered users, so that WWTravelClub can guarantee good service quality
  • US_015: As an administrator user, I want to manage expert users, so that all of the questions regarding our destinations are answered
  • US_016: As an administrator user, I want to offer more than 1,000 packages around the world, so that different countries can experience the WWTravelClub service
  • US_017: As the CEO, I want to have more than 1,000 users simultaneously accessing the website, so that the business can scale effectively
  • US_018: As a user, I want to access WWTravelClub in my native language, so that I can easily understand the package offered
  • US_019: As a user, I want to access WWTravelClub in the Chrome, Firefox, and Edge web browsers, so that I can use the web browser of my preference
  • US_020: As a user, I want to know my credit card information is stored securely, so I can buy packages safely

Notice that while you start writing the stories, information related to non-functional requirements such as security, environment, performance, and scalability can be included.

However, some system requirements may be omitted when you write user stories and need to be included in the software specification. These requirements can be related to legal aspects, hardware, and software prerequisites, or even points of attention for the correct system delivery. They need to be mapped and listed as well as user stories. The WWTravelClub system requirements are presented in the following list. Notice that requirements are written in the future because the system does not exist yet:

  • SR_001: The system shall use Microsoft Azure components to deliver the scalability required
  • SR_002: The system shall respect General Data Protection Regulation (GDPR) requirements
  • SR_003: The system shall run on the Windows, Linux, iOS, and Android platforms
  • SR_004: Any web page of this system shall respond in at least 2 seconds with a 1,000-user concurrently access

The idea of having this list of user stories and system requirements is to help you understand how complex the development of a platform might be if you think about it from an architectural perspective.



In this chapter, you learned the purpose of a software architect in a software development team. Also, this chapter covered the basics of software development process models and the requirements gathering process. You also had the opportunity to learn about how to create your Azure account, which will be used during the case study of this book, which was presented to you in the previous section. Moreover, you even learned about functional and non-functional requirements and how to create them using user stories. These techniques will help you deliver a better software project.

In the next chapter, you will have the opportunity to understand how important functional and non-functional requirements are for software architecture.



  1. What is the expertise that a software architect needs to have?
  2. How can Azure help a software architect?
  3. How does a software architect decide the best software development process model to use in a project?
  4. How does a software architect contribute to gathering requirements?
  5. What kind of requirements does a software architect need to check in a requirement specification?
  6. How do Design Thinking and Design Sprint help a software architect in the process of gathering requirements?
  7. How do user stories help a software architect in the process of writing requirements?
  8. What are good techniques to develop very good performance software?
  9. How does a software architect check whether a user requirement is correctly implemented?
About the Authors
  • Gabriel Baptista

    Gabriel Baptista is a software architect who leads technical teams for Microsoft products across numerous projects for retail and industry. He is an Azure Platform-as-a-Service (PaaS) solutions specialist, a computing professor, a co-founder of a start-up for developing mobile applications, and also a speaker on the Channel 9 community.

    Browse publications by this author
  • Francesco Abbruzzese

    Francesco Abbruzzese has built the tool - MVC Controls Toolkit. He has contributed to the evangelization of the Microsoft web stack since the first version of ASP.NET MVC through tutorials, articles, and tools that can be found on his blog, Dot Net Programming, and in various online magazines. His company, Mvcct Team, implements and offers web applications and AI software associated with the Microsoft stack.

    Browse publications by this author
Latest Reviews (2 reviews total)
Bom material editorial. Boa qualidade gráfica.
Very comprehensive book covering a wide range of topics in the new .NET universe.
Software Architecture with C# 9 and .NET 5 - Second Edition
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