Preface

The book begins with an introduction to the new features of C# 7 and .NET Core 2.0, and how they help improve the performance of your application. The book will then help you understand the core internals of .NET Core, which includes the compilation process, garbage collection, utilizing multiple cores of the CPU to develop highly-performant applications, and measuring performance using a powerful library for benchmarking applications named BenchmarkDotNet. We will learn about developing applications and programs using multithreading and asynchronous programming, and how to use those concepts to build efficient applications for faster execution. Next, you'll understand the importance of data structure optimization and how it can be used efficiently. We move on to the patterns and best practices to use when designing applications in .NET Core, along with how to utilize memory in an effective way and avoid memory leakage. After that, we'll talk about implementing security and resiliency in .NET Core applications, and we'll use the Polly framework to implement a circuit breaker, and retry and fallback patterns, along with certain middleware to harden the HTTP pipeline. We'll also implement security such as authorization and authentication using the Identity framework. Moving ahead, we will learn about the microservices architecture and see how we can use it to create applications that are modular, highly scalable, and independently deployable. We end with App Metrics, and will learn how to use it to monitor the performance of your application.

Who this book is for

This book is for .NET developers who want to improve the speed of their application's code or who simply want to take their skills to the next level, where they can develop and produce quality applications that are not only performant but also adhere to the industry best practices. Basic C# knowledge is assumed.

What this book covers

Chapter 1, What's New in .NET Core 2 and C# 7?, discusses the .NET Core Framework and covers some improvements that were introduced with .NET Core 2.0. We will also look into the new features of C# 7 and see how we can write cleaner code and simplify syntactic expressions. Lastly, we cover the topic of writing quality code. We'll see how we can leverage the Code analysis feature of Visual Studio 2017 to add analyzers to our project and improve code quality.

Chapter 2, Understanding .NET Core Internals and Measuring Performance, discusses the core concepts of .NET Core, including the compilation process, garbage collection, building highly-performant .NET Core applications utilizing multiple cores of the CPU, and publishing an application using a release build. We will also explore the benchmarking tool that is highly used for code optimization and provides results specific to in-memory objects.

Chapter 3, Multithreading and Asynchronous Programming in .NET Core, explores the core fundamentals of multithreaded and asynchronous programming. The chapter starts with the basic differences between multithreaded and asynchronous programming and walks you through the core concepts. It explores APIs and how to use them when writing a multithreaded application. We will learn how the Task Programming Library can be used to serve asynchronous operations, and how to implement the Task Asynchronous pattern. Lastly, we will explore parallel programming techniques and some of the best design patterns being used.

Chapter 4, Data Structures and Writing Optimized Code in C#, outlines the core concepts of data structures, the types of data structure, and their advantages and disadvantages, followed by the best possible scenarios to which each data structure is suited. We also learn about the Big O notation, which is one of the core topics to consider when writing code and helps developers check the quality of the code and performance. Lastly, we will look into some best practices and cover topics such as boxing and unboxing, string concatenation, exception handling, for and foreach, and delegates.

Chapter 5, Designing Guidelines for .NET Core Application Performance, showcases some coding principles that make application code look clean and easy to understand. If the code is clean, it offers other developers a way to understand it completely and helps in many other ways. We will learn some basic design principles that are considered to be part of the core principles when designing applications. Principles such as KISS, YAGNI, DRY, Separation of Concerns, and SOLID are highly essential in software design, and caching and choosing the right data structure have a significant impact on performance, and can improve performance if they are properly used. Lastly, we will learn some best practices that should be considered when handling communication, resource management, and concurrency.

Chapter 6, Memory Management Techniques in .NET Core, outlines the underlying process of how memory management is done in .NET. We will explore the debugging tool, which can be used by developers to investigate the object's memory allocation on the heap. We will also learn about memory fragmentation, finalizers, and how to implement a dispose pattern to clean up resources by implementing the IDisposable interface.

Chapter 7, Securing and Implementing Resilience in .NET Core Applications, takes you through resiliency, which is a very important factor when developing highly-performant applications in .NET Core. We will learn different policies and use the Polly framework to use those policies in .NET Core. We will also learn about safe storage mechanisms and how to use them in the development environment in order to keep sensitive information separate from the project repository. At the end of this chapter, we will learn some security fundamentals, which include SSL, CSRF, CORS, security headers, and the ASP.NET Core Identity framework, in order to protect ASP.NET Core applications.

Chapter 8, Microservices Architecture, looks at the most quickly evolving software architecture for developing highly performant and scalable applications for the cloud based on microservices. We will learn some of the core fundamentals of the microservices architecture, its benefits, and patterns and practices used when designing the architecture. We will discuss certain challenges faced when decomposing enterprise applications into the microservices architecture style and learn patterns such as API composition and CQRS in order to address them. Later in the chapter, we will develop a basic application in .NET Core and discuss the solution's structure and the components of microservices. Then we will develop identity and vendor services.

Chapter 9, Monitoring Application Performance Using Tools, dives into key performance metrics that are essential for monitoring an application's performance. We will explore and set up App Metrics, which is a free tool that is cross-platform and provides various extensions that can be used to achieve extensive reporting. We will go through a step-by-step guide on how to configure and set up App Metrics and related components, such as InfluxDb and Grafana, which is used to store and view telemetry in the Grafana web-based tool and integrate it with ASP.NET Core application.

To get the most out of this book

The readers should be equipped with the following configurations of the environment:

1. Development Environment: Visual Studio 2015/2017 Community Edition
2. Execution Environment: .NET Core
3. OS Environment: Windows or Linux

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Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Mount the downloaded WebStorm-10*.dmg disk image file as another disk on your system."

A block of code is set as follows:

public static IWebHost BuildWebHost(string[] args) => 
  WebHost.CreateDefaultBuilder(args) 
    .UseMetrics() 
    .UseStartup<Startup>() 
    .Build(); 

Any command-line input or output is written as follows:

Install-Package App.Metrics 
Install-Pacakge App.Metrics.AspnetCore.Mvc 

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