Programming Backend with Go

Programming Backend with Go

Build robust and scalable backends for your applications using the efficient and powerful tools of the Go ecosystem

Julian Braun

Prologue

You have arrived at Programming Backend with Go. Hi! I'm Julian Braun, and I can't wait to show you all the cool stuff about Go backend development. Working with Go for many years has shown me how effective and efficient it is for building scalable, high-performance backend systems. I hope that this book will be useful to you whether you are an experienced developer or just getting your feet dipped in the world of backend programming. The Google Go language, also known as Golang, is known for its simplicity, efficiency, and dependability. When speed and scalability are of the utmost importance, it excels in backend development. We will build real-world apps and services that can handle the demands of modern web environments by exploring how to harness Go's full potential throughout this book.

To get things rolling, we'll setup our development environment and make sure you have everything you need to get things done. I'll show you how to set up Visual Studio Code, install Go, and use Go modules to manage dependencies. A well-configured environment can greatly enhance your productivity and development ease, so this foundational step must be taken for anyone interested in diving into Go programming. After everything is ready to go, we will learn using Go's net/http package to build web servers. The book will teach you the ins and outs of serving static files, responding to requests, and routing various URLs to their respective handlers. As a foundation for more advanced topics, these skills are the bedrock of web development.

In subsequent sections, we will learn more complex routing methods implemented within the gorilla/mux package. With this robust library, you can easily build sophisticated web applications with more expressive and flexible URL handling. Additionally, we will discuss error handling, custom handlers, and middleware to make sure your applications are strong and easy to maintain.

Extensive coverage of security will be provided, as it is an essential component of backend development. You will discover how to construct secure apps that safeguard users' and data's information, from incorporating user authentication with OAuth2 and JWT to protecting your apps from typical vulnerabilities such as SQL injection and XSS attacks.

Go stands out due to its top-notch concurrency and parallelism support. We'll make the most of this by creating and implementing microservices. You will discover how to create, launch, and oversee scalable microservices using tools like Gin and Kubernetes. In addition, we will go over REST and gRPC for inter-service communication, which will equip you to construct service-oriented architectures that are both efficient and cohesive.

The ability to efficiently manage data is fundamental to many applications, and GORM will teach you just that. The fundamentals of CRUD operations as well as more complex features like transactions, migrations, and concurrency control will all be covered. In addition, you will gain knowledge of message brokering with Apache Kafka  and NSQ, which will equip you to create apps that can manage asynchronous workloads with high throughput. We will learn tools like Delve, Testify, and GoMock, which are essential for any developer, to help with testing and debugging. You'll learn how to write thorough tests, mock dependencies, and debug applications to ensure reliability and bug-freeness.

At last, we'll talk about deployment strategies, such as blue-green, canary, and rolling. By learning how to automate your deployment process with AWS CodeDeploy, you can keep your applications running smoothly and up-to-date at all times. More than simply a book, Programming Backend with Go is an all-inclusive manual for turning you into an expert Go backend developer. The knowledge and abilities you acquire here will be very useful regardless of the complexity of the systems you're developing, be it simple web applications or complex distributed systems. Therefore, I say we jump right in and start making magic.

Copyright © 2024 by GitforGits

All rights reserved. This book is protected under copyright laws and no part of it may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without the prior written permission of the publisher. Any unauthorized reproduction, distribution, or transmission of this work may result in civil and criminal penalties and will be dealt with in the respective jurisdiction at anywhere in India, in accordance with the applicable copyright laws.

Published by: GitforGits

Publisher: Sonal Dhandre

www.gitforgits.com

[email protected]

Printed in India

First Printing: April 2024

Cover Design by: Kitten Publishing

For permission to use material from this book, please contact GitforGits at [email protected].

Content

Preface

GitforGits

Acknowledgement

Chapter 1: Understanding Go for Backend Development

Chapter Overview

Go and its Ecosystem

Core Features

Standard Library

Go Modules and Package Management

Popular Libraries for Backend Development

Messaging and Stream Processing

Security and Authentication

Containerization and Virtualization

Networking and Protocols

Testing and Deployment

Installing Go

Preparation and Download

Installation

Setting up the Environment

Verification

Setting up Visual Studio Code

Installing VS Code and Go Extension

Configuring Go Extension

Setting up the Workspace

Debugging Setup

Testing Integration

Go Modules for Package Management

What are Go Modules?

Setting up New Module

Adding Dependencies

Understanding go.mod File

Using go.sum File

Managing Upgrades and Downgrades

Basics of a Go program

Basic Structure of a Go Program

Variables and Types

Control Structures

If statement

For loop

Switch statement

Arrays, Slices, and Maps

Arrays

Slices

Maps

Functions

Concurrency with Goroutines

Introduction to ‘gitforgits.com’ Project

Project Overview

Functional Requirements

Technical Requirements

Design Considerations

Quick Project Code Structure

Git for Version Control

Why use Git?

Basic Git Commands

Adding Files and Committing Changes

Branching

Viewing Changes and Logs

Merging Branches

Handling Merge Conflicts

Using Git with Remote Repositories

Docker Basics

What are Docker Containers?

Images and Containers

Dockerfile

Building and Running Docker Containers

Docker Compose

Starting and Managing Project Containers

Volumes and Networks

Summary

Chapter 2: Building a Basic Web Server with net/http

Chapter Overview

Introduction to ‘net/http’ Package

Core Components of net/http

Working with HTTP Servers

Deep Dive into HTTP Handlers

Understanding Request and Response

Creating your first web server

Setup Basic HTTP Server

Handling Different Routes

Handling HTTP Methods

Query Parameters and URL Fragments

Running and Testing Server

Understanding Request and Response Structures

HTTP Request Structure

HTTP Response Structure

Flow of Request and Response

Client Request

Server Handling

Server Response

Client Receives

Handling of Requests and Responses

Basics of Routing with http.ServeMux

Understanding Routing

Introduction to http.ServeMux

Features of http.ServeMux

Sample Program: Routing with http.ServeMux

Handling Different HTTP Methods

HTTP Methods

GET

POST

PUT

DELETE

PATCH

HEAD

OPTIONS

TRACE

CONNECT

Sample Program: Implementing Handlers

Query Parameters and URL Fragments

Importance of Query Parameters and URL Fragments

Query Parameters

URL Fragments

Sample Program: Utilizing Query Parameters and URL Fragments

Handling Query Parameters

URL Fragments for Client-Side Handling

Testing Implementation

Serving Static Files and Assets

Types of Static Files and Assets

Serving Static Files

Structuring Static Directory

Testing Static File Serving

Structuring Go Web Application

Project Structure Overview

Directories Overview

Sample Program: Adopting Structure in gitforgits.com

Summary

Chapter 3: Advanced Routing with gorilla/mux

Chapter Overview

Introduction to gorilla/mux

Why Gorilla Mux?

Up and Running with Gorilla Mux

Advanced Routing Techniques

Regular Expression Constraints

Subdomain Routing

Query Parameter Routing

Path Variables

Defining Path Variables

Accessing Path Variables

Managing Path Variables

Regex-based Routing

Understanding Regex

Advantages of Regex-Based Routing

Implementing Regex-Based Routing

Testing Regex-Based Routing

Custom Handlers and Middleware

Purpose of Custom Handlers and Middleware

Creating Custom Handlers and Middleware in Gorilla Mux

Custom Handlers

Middleware

Sample Program: Manage Routing with Custom Handlers

Error Handling and HTTP Status Codes

Understanding HTTP Status Codes

Implementing Error Handling

Custom Error Handler

Using Middleware for Error Handling

Sample Program: Handling Specific Errors

Perform RESTful Routing

Understanding RESTful Routing

Implementing RESTful Routing using Gorilla Mux

Setting up Gorilla Mux Router

Defining Handler Functions

Building CRUD Operations

Setting up the Environment

Defining Book Model

Building Handlers

Create (POST)

Read (GET)

Update (PUT)

Delete (DELETE)

Assembling the Router and Starting the Server

Summary

Chapter 4: User Authentication with Oauth2 and JWT

Chapter Overview

Basics of User Authentication

What is User Authentication?

Working of User Authentication

Credential Verification

Session Creation and Management

Using Authentication to Protect Routes

Using OAuth2 with Go

Setting up OAuth2

Register the Application

Setting up OAuth2 Client

Flows in OAuth2

Integration with Social Media Logins

Integration with Google Login

Integration with Facebook Login

Setting up Facebook OAuth Configuration

Handling Facebook Callback

Integration with Email Login

Implementing JWT for Secure APIs

Advantages of JWT for Secure APIs

Implementing JWT

Install the JWT Go Package

Create the JWT Token

Setup HTTP Endpoint to use JWT

Create Middleware to Protect Routes

Sessions and Cookie Management

Understanding Sessions and Cookies

Managing Cookie-Based User Sessions

Secure Session Management Techniques

User registration and Password Management

Creating System for User Registration and Password Mgmt

User Registration API

Managing and Protecting Passwords

Defining Password Policies

Rate Limiting and Abuse Prevention

Understanding Rate Limiting

Implementing Custom Rate Limiting

Define Rate Limiter Structure

Integrating Rate Limiting

Protecting against DDoS Attacks

Summary

Chapter 5: Integrating Databases with GORM

Chapter Overview

Setting up GORM for ORM

Introduction to GORM

Setting up GORM in Development Environment

Install GORM

Connect to the Database

Define Models

Perform Migrations

Database Selection for Application

Common Databases used in Go Apps

Choosing PostgreSQL

Designing Database Schema

Integrating PostgreSQL with GORM

Database CRUD Operations

Setting up the Environment

CRUD Operations in GORM

Create (Inserting Data)

Read (Querying Data)

Update (Modifying Data)

Delete (Removing Data)

Advanced GORM Features

Understanding Hooks in GORM

Commonly Used GORM Hooks

Sample Program: Implementing a Hook

Understanding Scopes in GORM

Putting Hooks and Scopes into Practice

Auto-Logging Changes

Advanced Scopes for Complex Queries

Managing Database Migrations

Understanding Database Migrations

GORM's Migration Features

Sample Program: Migration with GORM

Initial Setup

Adding New Model with Relationships

Modifying Existing Schema

Transactions and Concurrency Control

Understanding Transactions

Using GORM to Manage Transactions

Concurrency Control

Managing Concurrency

Summary

Chapter 6: Creating Microservices in Go

Chapter Overview

Design Principles for Microservices

Decomposition by Business Capability

Independence and Decentralization

Failure Isolation

Automate Everything

Observability

Setting up Microservices Environment

Introduction to Gin Framework

Capabilities of Gin

Setting up Gin for gotforgits.com

Install Gin

Create a Basic Gin Server

Test Your Setup

Inter-service Communication with REST and gRPC

Overview

Choosing Communication Protocols: REST vs. gRPC

REST for Inter-service Communication

gRPC for Inter-service Communication

Setting up REST and gRPC

Install Necessary Packages

Creating ProductService with REST

Creating ProductService with gRPC

Creating ClientService

Conclusion

Using gRPC and Protocol Buffers

Introduction to Protocol Buffers and gRPC

What are Protocol Buffers?

Why gRPC?

Service Interfaces and Message Structures with Protocol Buffers

Install Protocol Buffers Compiler

Define Proto File

Compile Proto File

How gRPC utilizes Protocol Buffers?

Implementing Service

Creating the Client

Implementing API Gateways

Introduction to API Gateways

Significance of an API Gateway

Implementing an API Gateway

Install Kong

Configure Service Routing

Handling Failures

Implementing Aggregations

Authentication and Authorization in Microservices

Introduction to Authentication and Authorization

Strategies for Securing Microservices

Centralized Identity and Access Management

Using API Gateways for Security

Implementing Authentication and Authorization

Setup Authentication at the API Gateway

Microservice Authorization

Containerize Microservices with Kubernetes

Introduction to Kubernetes and Containerization

Setting up Kubernetes

Install Minikube and kubectl

Start Minikube

Understanding Containerization

Install Docker

Containerizing Microservices using Gin

Create a Dockerfile

Build and Run Your Docker Container

Deploying to Kubernetes

Summary

Chapter 7: Message Brokering with NSQ and Apache Kafka

Chapter Overview

Introduction to Message Brokering

Concept of Message Brokering

What is a Message Broker?

Benefits of Asynchronous Communication

Setting up NSQ

Key Features of NSQ

Setting up NSQ in Development Environment

Install NSQ

Run ‘nsqlookupd’

Run ‘nsqd’

Run ‘nsqadmin’

Testing NSQ Setup

Integrating Apache Kafka with Go

Installing Apache Kafka

Integrating Kafka with Go

Install Kafka Go Client Library

Writing a Kafka Producer

Writing a Kafka Consumer

Handling Message Patterns

Understanding Pub/Sub and Queues

Implementing Pub/Sub and Queues

Implementing Pub/Sub with Kafka

Implementing Queues with NSQ

Ensuring Message Delivery and System Resilience

Key Concepts

Message Delivery Guarantees

System Resilience

Implementation Strategies

Scenario 1: Ensuring At-Least-Once Delivery in Kafka

Scenario 2: Handling Failures and Redundancies in NSQ

Scaling and Managing Brokers

Scaling NSQ

Scaling Kafka Horizontally

Adding More Brokers

Partition Rebalancing

Replication Factor

Monitoring and Managing Performance

Summary

Chapter 8: Securing Go Applications

Chapter Overview

Secure Coding Practices

Source Code and Binaries Checks

Source Code Analysis

Binaries Analysis

Updating Dependencies and Go

Fuzz Testing

Race Detection

Using Go's Vet Command

Using HTTPS with Crypto/TLS

Understanding crypto/tls Package

Setting up HTTPS Server with TLS

Generate TLS Certificates

Configure HTTPS Server

Test HTTPS Server

Securing Headers and Cookies

Configuring HTTP Headers Securely

Content-Security-Policy (CSP)

X-Content-Type-Options

X-Frame-Options

Strict-Transport-Security

Securely Configuring Cookies

Sample Program: Configuring Headers and Cookies

Preventing SQL Injections and XSS Attacks

Prevent SQL Injections

Use Prepared Statements (Parameterized Queries)

Escaping All User Inputs

Prevent XSS Attacks

Encoding and Escaping User Input

Use Content Security Policy (CSP)

OAuth2 and JWT for Secure Data Access

Implementing OAuth2

Implementing JWT for Secure Data Access

Summary

Chapter 9: Testing and Debugging Go Applications

Chapter Overview

Unit Testing with Testify

What is Testify?

Installing Testify

Writing First Test with Testify

Define Book Service

Setup Test Files and Write Tests

Running Tests

Mocking Dependencies with GoMock

What is GoMock?

Installing GoMock

Setting up GoMock for Project

Writing Tests using GoMock

Profiling Go Apps using ‘pprof’

What is pprof?

Setting up Profiling

Integrate pprof with Go Application

Running Your Application

Accessing Profiling Data

Analyzing Profile Data

Run Logging with Zerolog

Installing Zerolog

Setting up Zerolog

Sample Program: Logging using Zerolog

Debugging and Troubleshooting with Delve

Installing Delve

Sample Program: Debugging Scenarios

Scenario