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Course Introduction

Course Overview

Introduction to Go

A Quick Introduction to Go The Advantages of Go Accessing Go Documentation Writing Our First Program Running Go Code Important Characteristics of Go: Variables Important Characteristics of Go: Control Important Characteristics of Go: Loops Important Characteristics of Go: Getting User Input Important Characteristics of Go: Error Variables Important Characteristics of Go: Concurrency Model Developing the which(1) Utility in Go Logging Information I Logging Information II Overview of Go Generics Developing a Basic Phone Book Application Exercise: Introduction to Go Solution: Introduction to Go Recap: Introduction to Go

Basic Go Data Types

Introduction The error Data Type Numeric Data Types Non-Numeric Data Types Integer Conversions: Unicode vs. String Values The strings Package Times and Dates A Utility for Parsing Dates and Times Working with Different Time Zones Go Constants Grouping Similar Data: Arrays and Slices Slice: Length and Capacity Selecting a Part of a Slice Byte Slices Deleting an Element from a Slice Connection Between Slices and Arrays The copy() Function Sorting Slices Pointers Generating Random Numbers Generating Random Strings Generating Secure Random Numbers Updating the Phone Book Application Exercise: Basic Go Data Types Solution: Basic Go Data Types Recap: Basic Go Data Types

Composite Data Types

Introduction Maps Storing to a Nil Map Iterating over Maps Go Structures Slices of Structures Regular Expressions and Pattern Matching Matching Names and Surnames Matching Integers Matching the Fields of a Record Improving the Phone Book Application I Improving the Phone Book Application II Exercise 1: Composite Data Types Solution 1: Composite Data Types Exercise 2: Composite Data Types Solution 2: Composite Data Types Recap: Composite Data Types

Reflection and Interfaces

Introduction Reflection Learning the Internal Structure of a Go Structure Changing Structure Values Using Reflection Type Methods Interfaces The sort.Interface Interface The Empty Interface Type Assertions and Type Switches Safely Handling Arbitrary Data The error Data Type Writing Our Own Interfaces I Writing Our Own Interfaces II Working with Two Different CSV File Formats Limitations of Object-Oriented Programming in Go Updating the Phone Book Application I Updating the Phone Book Application II Exercise 1: Reflection and Interfaces Solution 1: Reflection and Interfaces Exercise 2: Reflection and Interfaces Solution 2: Reflection and Interfaces Recap: Reflection and Interfaces

Go Packages and Functions

Naming Return Values in Go Functions

Functions That Accept Other Functions as Parameters

Functions That Return Other Functions

Variadic Functions

The defer Keyword

Developing Our Own Packages

Using GitHub to Store Go Packages

A Package for Working with a Database

Getting to Know Our Database

The Design and Implementation of the Go Package

Testing the Go Package

Modules and Creating Better Packages

Generating Documentation

GitLab Runners and Go

GitHub Actions and Go

Versioning Utilities

Exercise 1: Go Packages and Functions

Solution 1: Go Packages and Functions

Exercise 2: Go Packages and Functions

Solution 2: Go Packages and Functions

Exercise 3: Go Packages and Functions

Solution 3: Go Packages and Functions

Recap: Go Packages and Functions

Telling a UNIX System What to Do

Introduction UNIX Operating System Handling UNIX Signals File I/O Buffered and Unbuffered File I/O Reading Text Files Reading a Text File Word by Word Reading a Text File Character by Character Reading from /dev/random Reading a Specific Amount of Data from a File Writing to a File Working with JSON Structures and JSON Reading and Writing JSON Data as Streams Pretty Printing JSON Records Working with XML Converting JSON to XML and Vice Versa Working with YAML The viper Package: Using Command-Line Flags The viper Package: Reading JSON Configuration Files The cobra Package I The cobra Package II Finding Cycles in a UNIX File System Embedding Files ReadDir and DirEntry The io/fs Package Updating the Phone Book Application Exercise 1: Telling a UNIX System What to Do Solution 1: Telling a UNIX System What to Do Exercise 2: Telling a UNIX System What to Do Solution 2: Telling a UNIX System What to Do Exercise 3: Telling a UNIX System What to Do Solution 3: Telling a UNIX System What to Do Exercise 4: Telling a UNIX System What to Do Solution 4: Telling a UNIX System What to Do Recap: Telling a UNIX System What to Do

Go Concurrency

Introduction Processes, Threads, and Goroutines The Go Scheduler The GOMAXPROCS Environment Variable Goroutines Creating Multiple Goroutines Waiting for Our Goroutines to Finish What If the Number of Add() and Done() Calls Differ?Creating Multiple Files with Goroutines Channels Receiving from a Closed Channel Channels as Function Parameters Race Conditions The select Keyword Timing Out a Goroutine Closing Go Channels Buffered Channels nil Channels Worker Pools Signal Channels Shared Memory and Shared Variables What Happens If We Forget to Unlock a Mutex?The sync.RWMutex Type The atomic Package Sharing Memory Using Goroutines Closured Variables and the go Statement The context Package Using context as a Key/Value Store The semaphore Package Exercise 1: Go Concurrency Solution 1: Go Concurrency Exercise 2: Go Concurrency Solution 2: Go Concurrency Exercise 3: Go Concurrency Solution 3: Go Concurrency Exercise 4: Go Concurrency Solution 4: Go Concurrency Exercise 5: Go Concurrency Solution 5: Go Concurrency Recap: Go Concurrency

Building Web Services

Introduction The net/http Package Creating a Web Server Updating the Phone Book Application Using Prometheus for Performance Evaluation Exposing Metrics Creating a Docker Image for a Go Server Exposing the Desired Metrics Using Prometheus and Grafana to Visualize the Metrics Developing Web Clients Using http.NewRequest() to Improve the Client Creating a Client for the Phone Book Service Creating File Servers Downloading the Contents of the Phone Book Application Timing Out HTTP Connections Setting the Timeout Period on the Client Side Setting the Timeout Period on the Server Side Exercise 1: Building Web Services Solution 1: Building Web Services Exercise 2: Building Web Services Solution 2: Building Web Services Exercise 3: Building Web Services Solution 3: Building Web Services Exercise 4: Building Web Services Solution 4: Building Web Services Recap: Building Web Services

Working with TCP/IP and WebSocket

Introduction TCP/IP Developing a TCP Client Developing a TCP Client That Uses net.DialTCP()Developing a TCP Server Developing a TCP Server That Uses net.ListenTCP()Developing a UDP Client Developing a UDP Server Developing Concurrent TCP Servers Working with UNIX Domain Sockets A UNIX Domain Socket Client Creating a WebSocket Server The Implementation of the Server Using JavaScript Creating a WebSocket Client Exercise 1: Working with TCP/IP and WebSocket Solution 1: Working with TCP/IP and WebSocket Exercise 2: Working with TCP/IP and WebSocket Solution 2: Working with TCP/IP and WebSocket Exercise 3: Working with TCP/IP and WebSocket Solution 3: Working with TCP/IP and WebSocket Exercise 4: Working with TCP/IP and WebSocket Solution 4: Working with TCP/IP and WebSocket Exercise 5: Working with TCP/IP and WebSocket Solution 5: Working with TCP/IP and WebSocket Recap: Working with TCP/IP and WebSocket

Working with REST APIs

Introduction An Introduction to REST Developing RESTful Servers and Clients A RESTful Server A RESTful Client Creating a Functional RESTful Server Working with the Database Testing the restdb Package Implementing the RESTful Server Testing the RESTful Server Creating a RESTful Client Uploading and Downloading Binary Files Using Swagger for REST API Documentation Exercise 1: Working with REST APIs Solution 1: Working with REST APIs Exercise 2: Working with REST APIs Solution 2: Working with REST APIs Exercise 3: Working with REST APIs Solution 3: Working with REST APIs Exercise 4: Working with REST APIs Solution 4: Working with REST APIs Recap: Working with REST APIs

Code Testing and Profiling

Introduction Benchmarking Code I Benchmarking Code II Profiling Code I Profiling Code II The go tool trace Utility Tracing a Web Server from a Client Visiting All Routes of a Web Server Testing Go Code The TempDir Function The testing/quick Package Testing Code Coverage Finding Unreachable Go Code Testing an HTTP Server with a Database Backend Fuzzing Cross-Compilation Using go:generate Creating Example Functions Exercise 1: Code Testing and Profiling Solution 1: Code Testing and Profiling Exercise 2: Code Testing and Profiling Solution 2: Code Testing and Profiling Exercise 3: Code Testing and Profiling Solution 3: Code Testing and Profiling Exercise 4: Code Testing and Profiling Solution 4: Code Testing and Profiling Exercise 5: Code Testing and Profiling Solution 5: Code Testing and Profiling Recap: Code Testing and Profiling

Working with gRPC

Introduction Introduction to gRPC Defining an Interface Definition Language File Developing a gRPC Server Developing a gRPC Client Exercise 1: Working with gRPC Solution 1: Working with gRPC Exercise 2: Working with gRPC Solution 2: Working with gRPC Exercise 3: Working with gRPC Solution 3: Working with gRPC Exercise 4: Working with gRPC Solution 4: Working with gRPC Exercise 5: Working with gRPC Solution 5: Working with gRPC Recap: Working with gRPC

Go Generics

Introduction Our First Generic Function Constraints Creating Constraints Defining New Data Types with Generics Using Generics in Go Structures Interfaces vs. Generics Reflection vs. Generics Exercise 1: Go Generics Solution 1: Go Generics Exercise 2: Go Generics Solution 2: Go Generics Exercise 3: Go Generics Solution 3: Go Generics Exercise 4: Go Generics Solution 4: Go Generics Recap: Go Generics

Conclusion

Appendix A—Go Garbage Collector

Introduction Garbage Collection The Tricolor Algorithm More About the Operation of the Go Garbage Collector Maps, Slices, and the Go Garbage Collector

Advanced Techniques in Go Programming/

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Versioning Utilities

Versioning Utilities

Let’s learn about the versioning utilities.

We'll cover the following...

Coding example
Let’s try our code

One of the most difficult tasks is to automatically and uniquely version command-line utilities, especially when using a CI/CD system. This lesson presents a technique that uses a GitHub value to version a command-line utility on the local machine.

Note: We can apply the same technique to GitLab—we need to search for the available GitLab variables and values and choose one that fits our needs.

This technique is used by both the docker and kubectl utilities, among others:

# docker version
Client: Docker Engine - Community
 Cloud integration: 1.0.4
 Version: 20.10.0
 API version: 1.41
 Go version: go1.13.15
 Git commit: 7287ab3
 Built: Tue Dec 8 18:55:43 2020
 OS/Arch: darwin/amd64
...

The output above shows that docker uses the Git commit value for versioning—we are going to use a slightly different value that is longer than the one used by docker. ...