Go Programming Cookbook: Over 85 recipes to build modular, readable, and testable Golang applications across various domains. 2 Ed

 Cover....1 Title Page....2 Copyright and Credits....3 Dedication....4 About Packt....5 Contributors....6 Table of Contents....8 Preface....16 Chapter 1: I/O and Filesystems....22 Technical requirements....23 Using the common I/O interfaces....23 How to do it.......24 How it works.......27 Using the bytes and strings packages....27 How to do it.......28 How it works.......32 Working with directories and files....32 How to do it.......32 How it works.......36 Working with the CSV format....37 How to do it.......37 How it works.......42 Working with temporary files....42 How to do it.......43 How it works.......45 Working with text/template and html/template....45 How to do it.......45 How it works.......52 Chapter 2: Command-Line Tools....53 Technical requirements....54 Using command-line flags....54 How to do it.......54 How it works.......58 Using command-line arguments....58 How to do it.......59 How it works.......62 Reading and setting environment variables....63 How to do it.......63 How it works.......67 Configuration using TOML, YAML, and JSON....67 How to do it.......68 How it works.......74 Working with Unix pipes....74 How to do it.......75 How it works.......77 Catching and handling signals....77 How to do it.......77 How it works.......80 An ANSI coloring application....80 How to do it.......80 How it works.......83 Chapter 3: Data Conversion and Composition....84 Technical requirements....84 Converting data types and interface casting....85 How to do it.......85 How it works.......89 Working with numeric data types using math and math/big....89 How to do it.......89 How it works.......93 Currency conversions and float64 considerations....93 How to do it.......93 How it works.......97 Using pointers and SQL NullTypes for encoding and decoding....97 How to do it.......98 How it works.......103 Encoding and decoding Go data....103 How to do it.......103 How it works.......107 Structure tags and basic reflection in Go....108 How to do it.......108 How it works.......113 Implementing collections via closures....114 How to do it.......114 How it works.......118 Chapter 4: Error Handling in Go....119 Technical requirements....119 Handling errors and the Error interface....120 How to do it.......120 How it works.......123 Using the pkg/errors package and wrapping errors....123 How to do it.......124 How it works.......127 Using the log package and understanding when to log errors....127 How to do it.......128 How it works.......130 Structured logging with the apex and logrus packages....131 How to do it.......131 How it works.......135 Logging with the context package....135 How to do it.......135 How it works.......138 Using package-level global variables....139 How to do it.......139 How it works.......142 Catching panics for long-running processes....142 How to do it.......142 How it works.......144 Chapter 5: Network Programming....145 Technical requirements....145 Writing a TCP/IP echo server and client....146 How to do it.......146 How it works.......149 Writing a UDP server and client....150 How to do it.......150 How it works.......154 Working with domain name resolution....154 How to do it.......155 How it works.......157 Working with WebSockets....157 How to do it.......158 How it works.......162 Working with net/rpc for calling remote methods....163 How to do it.......163 How it works.......166 Using net/mail for parsing emails....167 How to do it.......167 How it works.......169 Chapter 6: All about Databases and Storage....170 Using the database/sql package with MySQL....170 Getting ready....171 How to do it.......171 How it works.......175 Executing a database transaction interface....176 Getting ready....176 How to do it.......176 How it works.......180 Connection pooling, rate limiting, and timeouts for SQL....180 Getting ready....180 How to do it.......181 How it works.......183 Working with Redis....184 Getting ready....184 How to do it.......184 How it works.......188 Using NoSQL with MongoDB....188 Getting ready....189 How to do it.......189 How it works.......192 Creating storage interfaces for data portability....192 Getting ready....193 How to do it.......193 How it works.......197 Chapter 7: Web Clients and APIs....198 Technical requirements....198 Initializing, storing, and passing http.Client structures....199 How to do it.......199 How it works.......203 Writing a client for a REST API....203 How to do it.......204 How it works.......207 Executing parallel and async client requests....207 How to do it.......207 How it works.......210 Making use of OAuth2 clients....210 Getting ready....211 How to do it.......211 How it works.......214 Implementing an OAuth2 token storage interface....214 Getting ready....215 How to do it.......215 How it works.......220 Wrapping a client in added functionality and function composition....221 How to do it.......222 How it works.......225 Understanding GRPC clients....226 Getting ready....226 How to do it.......226 How it works.......230 Using twitchtv/twirp for RPC....230 Getting ready....231 How to do it.......231 How it works.......235 Chapter 8: Microservices for Applications in Go....236 Technical requirements....237 Working with web handlers, requests, and ResponseWriter instances....237 How to do it.......238 How it works.......241 Using structures and closures for stateful handlers....241 How to do it.......242 How it works.......246 Validating input for Go structures and user inputs....246 How to do it.......246 How it works.......250 Rendering and content negotiation....251 How to do it.......251 How it works.......254 Implementing and using middleware....254 How to do it.......255 How it works.......259 Building a reverse proxy application....259 How to do it.......259 How it works.......263 Exporting GRPC as a JSON API....263 Getting ready....263 How to do it.......264 How it works.......270 Chapter 9: Testing Go Code....271 Technical requirements....271 Mocking using the standard library....272 How to do it.......272 How it works.......276 Using the Mockgen package to mock interfaces....276 Getting ready....277 How to do it.......277 How it works.......280 Using table-driven tests to improve coverage....281 How to do it.......281 How it works.......283 Using third-party testing tools....284 Getting ready....284 How to do it.......284 How it works.......288 Behavior testing using Go....289 Getting ready....289 How to do it.......290 How it works.......293 Chapter 10: Parallelism and Concurrency....295 Technical requirements....296 Using channels and the select statement....296 How to do it.......296 How it works.......299 Performing async operations with sync.WaitGroup....300 How to do it.......300 How it works.......304 Using atomic operations and mutex....304 How to do it.......305 How it works.......308 Using the context package....309 How to do it.......309 How it works.......312 Executing state management for channels....312 How to do it.......313 How it works.......316 Using the worker pool design pattern....317 How to do it.......317 How it works.......322 Using workers to create pipelines....322 How to do it.......322 How it works.......327 Chapter 11: Distributed Systems....328 Technical requirements....328 Using service discovery with Consul....329 How to do it.......329 How it works.......332 Implementing basic consensus using Raft....333 How to do it.......333 How it works.......340 Using containerization with Docker....341 Getting ready....341 How to do it.......341 How it works.......345 Orchestration and deployment strategies....345 How to do it.......346 How it works.......349 Monitoring applications....349 How to do it.......349 How it works.......353 Collecting metrics....353 Getting ready....354 How to do it.......354 How it works.......357 Chapter 12: Reactive Programming and Data Streams....358 Technical requirements....358 Using Goflow for data flow programming....359 How to do it.......359 How it works.......362 Using Kafka with Sarama....363 Getting ready....363 How to do it.......363 How it works.......366 Using async producers with Kafka....366 Getting ready....367 How to do it.......367 How it works.......370 Connecting Kafka to Goflow....370 Getting ready....371 How to do it.......371 How it works.......374 Writing a GraphQL server in Go....375 How to do it.......375 How it works.......381 Chapter 13: Serverless Programming....382 Go programming on Lambda with Apex....382 Getting ready....383 How to do it.......383 How it works.......387 Apex serverless logging and metrics....387 Getting ready....388 How to do it.......388 How it works.......391 Google App Engine with Go....391 Getting ready....392 How to do it.......392 How it works.......396 Working with Firebase using firebase.google.com/go....397 Getting ready....397 How to do it.......398 How it works.......401 Chapter 14: Performance Improvements, Tips, and Tricks....402 Technical requirements....402 Using the pprof tool....403 How to do it.......403 How it works.......407 Benchmarking and finding bottlenecks....408 How to do it.......408 How it works.......412 Memory allocation and heap management....412 How to do it.......412 How it works.......415 Using fasthttprouter and fasthttp....416 How to do it.......416 How it works.......419 Other Books You May Enjoy....420 Index....423