What this book covers
Chapter 1, A Quick Introduction to Go, begins by talking about the history of Go, the important characteristics of Go, and the advantages of Go, before describing the godoc and go doc utilities and explaining how we can compile and execute Go programs. Afterward, the chapter talks about printing output and getting user input, working with command-line arguments, and using log files. Lastly, we develop a basic version of a phone book application that we are going to keep improving in forthcoming chapters.
Chapter 2, Basic Go Data Types, discusses the basic data types of Go, both numeric and non-numeric, as well as arrays and slices that allow you to group data of the same data type. It also considers Go pointers, constants, and working with dates and times. The last part of the chapter is about generating random numbers and populating the phone book application with random data.
Chapter 3, Composite Data Types, begins with maps, before going into structures and the struct keyword. Additionally, it talks about regular expressions, pattern matching, and working with CSV files. Lastly, we improve the phone book application by adding data persistency to it.
Chapter 4, Reflection and Interfaces, is about reflection, interfaces and type methods, which are functions attached to data types. The chapter also includes the use of the sort.Interface interface for sorting slices, the use of the empty interface, type assertions, type switches, and the error data type. Additionally, we discuss how Go can mimic some object-oriented concepts before improving the phone book application.
Chapter 5, Go Packages and Functions, is all about packages, modules, and functions, which are the main elements of packages. Among other things, we create a Go package for interacting with a PostgreSQL database, create documentation for it, and explain the use of the sometimes tricky defer keyword. This chapter also includes information about the use of GitLab Runners and GitHub Actions for automation and how to create a Docker image for a Go binary.
Chapter 6, Telling a UNIX System What to Do, is about systems programming, which includes subjects such as working with command-line arguments, handling UNIX signals, file input and output, the io.Reader and io.Writer interfaces, and the use of the viper and cobra packages. Additionally, we talk about working with JSON, XML, and YAML files, create a handy command-line utility for discovering cycles in a UNIX filesystem, and discuss embedding files in Go binaries as well as the os.ReadDir() function, the os.DirEntry type, and the io/fs package. Lastly, we update the phone book application to use JSON data and convert it into a proper command-line utility with the help of the cobra package.
Chapter 7, Go Concurrency, discusses goroutines, channels, and pipelines. We learn about the differences between processes, threads, and goroutines, the sync package, and the way the Go scheduler operates. Additionally, we explore the use of the select keyword and we discuss the various "types" of Go channels as well as shared memory, mutexes, the sync.Mutex type, and the sync.RWMutex type. The rest of the chapter talks about the context package, the semaphore package, worker pools, how to time out goroutines, and how to detect race conditions.
Chapter 8, Building Web Services, discusses the net/http package, the development of web servers and web services, exposing metrics to Prometheus, visualizing metrics in Grafana, creating web clients and creating file servers. We also convert the phone book application into a web service and create a command-line client for it.
Chapter 9, Working with TCP/IP and WebSocket, is about the net package, TCP/IP, and the TCP and UDP protocols, as well as UNIX sockets and the WebSocket protocol. We develop lots of network servers and clients in this chapter.
Chapter 10, Working with REST APIs, is all about working with REST APIs and RESTful services. We learn how to define REST APIs and develop powerful concurrent RESTful servers as well as command-line utilities that act as clients to RESTful services. Lastly, we introduce Swagger for creating documentation for REST APIs and learn how to upload and download binary files.
Chapter 11, Code Testing and Profiling, discusses code testing, code optimization, and code profiling as well as cross-compilation, benchmarking Go code, creating example functions, the use of go:generate, and finding unreachable Go code.
Chapter 12, Working with gRPC, is all about working with gRPC in Go. gRPC is an alternative to RESTful services that was developed by Google. This chapter teaches you how to define the methods and the messages of a gRPC service, how to translate them into Go code, and how to develop a server and a client for that gRPC service.
Chapter 13, Go Generics, is about generics and how to use the new syntax to write generic functions and define generic data types. Generics is coming to Go 1.18, which, according to the Go development cycle, is going to be officially released during February 2022.
Appendix A, Go Garbage Collector, talks about the operation of the Go garbage collector and illustrates how this Go component can affect the performance of your code.