Go for DevOps: Learn how to use the Go language to automate servers, the cloud, Kubernetes, GitHub, Packer, and Terraform

Cover
Title Page
Copyright
Dedication
Contributors
Table of Contents
Preface

Section 1: Getting Up and Running with Go
Chapter 1: Go Language Basics
____Technical requirements
____Using the Go Playground
____Utilizing Go packages
________Declaring a package
________Importing a package
________Using a package
________Package name conflicts
________Packages must be used
________A Go Hello World
____Using Go\'s variable types
________Go\'s types
________Declaring variables
________Variable scopes and shadowing
________Function/statement variable must be used
____Looping in Go
________C style
________Removing the init statement
________Remove the post statement too and you have a while loop
________Creating an infinite loop
____Using conditionals
________if statements
________else
____Learning about functions
________Returning multiple values and named results
________Variadic arguments
________Anonymous functions
____Defining public and private
____Using arrays and slices
________Arrays
________Slices
________Extracting all values
________Understanding maps
________Declaring a map
________Accessing values
________Adding new values
________Extracting all values
____Understanding Go pointers
________Memory addresses
________Function arguments are copies
________Pointers to the rescue
____Getting to know about structs
________Declaring a struct
________Declaring a custom type
________Custom struct types
________Adding methods to a type
________Changing a field\'s value
________Changing a field\'s value in a method
________Constructors
____Comprehending Go interfaces
________Defining an interface type
________Important things about interfaces
________The blank interface – Go\'s universal value
________Type assertion
____Summary

Chapter 2: Go Language Essentials
____Handling errors in Go
________Creating an error
________Using an error
________Creating named errors
________Custom errors
________Wrapping errors
____Utilizing Go constants
________Declaring a constant
________Enumeration via constants
________Printing enumerators
____Using defer, panic, and recover
________defer
________panic
________recover
____Utilizing goroutines for concurrency
________Starting a goroutine
________Synchronization
________WaitGroups
________Channels
________Sending/receiving
________select statements
________Channels as an event signal
________Mutexes
________RWMutex
____Understanding Go\'s Context type
________Using a Context to signal a timeout
________Honoring a context when receiving
________Context in the standard library
________Context to pass values
________Best practices
____Utilizing Go\'s testing framework
________Creating a basic test file
________Creating a simple test
________Table Driven Tests (TDT)
________Creating fakes with interfaces
________Third-party testing packages
____Generics – the new kid on the block
________Type parameters
________Using type constraints
________We could do better with constraints
________Current built-in constraints
________Type constraints with methods
________Adding type parameters to struct types
________Specifying the type when calling a generic function
________Gotchas to watch for
________When to use generics
____Summary

Chapter 3: Setting Up Your Environment
____Technical requirements
____Installing Go on your machine
________macOS installation using the package installer
________macOS installation via Homebrew
________Windows installation using MSI
________Linux
________Other platforms
________A note on Go compiler version compatibility
____Building code locally
________Creating a module directory and go.mod file
________Updating a module when adding dependencies
________Adding a hello world
________Running our first program
____Summary

Chapter 4: Filesystem Interactions
____All I/O in Go are files
________I/O interfaces
____Reading and writing to files
________Reading local files
________Writing local files
________Reading remote files
____Streaming file content
________Stdin/Stdout/Stderr are just files
________Reading data out of a stream
________Writing data into a stream
____OS-agnostic pathing
________What OS/platform am I running?
________Using filepath
________Relative and absolute pathing
____OS-agnostic filesystems
________io.fs filesystems
________embed
________Walking our filesystem
________The io/fs future
____Summary

Chapter 5: Using Common Data Formats
____Technical requirements
____CSV files
________Basic value separation using the strings package
________Using the encoding/csv package
________Using excelize when dealing with Excel
____Popular encoding formats
________The Go field tags
________JSON
________YAML encoding
____Summary

Chapter 6: Interacting with Remote Data Sources
____Technical requirements
____Accessing SQL databases
________Connecting to a Postgres database
________Querying a Postgres database
________Null values
________Writing data to Postgres
________Transactions
________Postgres-specific types
________Other options
________Storage abstractions
________Case study – data migration of an orchestration system – Google
____Developing REST services and clients
________REST for RPCs
____Developing gRPC services and clients
________Protocol buffers
________Stating the prerequisites
________Generating your packages
________Writing a gRPC client
________Writing a gRPC server
________Creating a server binary
________Creating a client binary
________Company-standard RPC clients and servers
____Summary

Chapter 7: Writing Command-Line Tooling
____Technical requirements
____Implementing application I/O
________The flag package
________Custom flags
________Basic flag error handling
________Shorthand flags
________Accessing non-flag arguments
________Retrieving input from STDIN
____Using Cobra for advanced CLI applications
________Code organization
________The optional Cobra generator
________The command package
____Handling OS signals
________Capturing an OS signal
________Using Context to cancel
____Summary

Chapter 8: Automating Command-Line Tasks
____Technical requirements
____Using os/exec to automate local changes
________Determining the availability of essential tools
____Using SSH in Go to automate remote changes
________Connecting to another system
____Designing safe, concurrent change automations
________Components of a change
________Writing a concurrent job
________Case study – Network rollouts
____Writing a system agent
________Designing a system agent
________Implementing Install
________Implementing SystemPerf
____Summary

Section 2: Instrumenting, Observing, and Responding

Chapter 9: Observability with OpenTelemetry
____Technical requirements
____An introduction to OpenTelemetry
________Reference architecture for OpenTelemetry
________OpenTelemetry components
____Logging with context
________Our first log statement
________Structured and leveled logs with Zap
________Ingesting, transforming, and exporting logs using OpenTelemetry
____Instrumenting for distributed tracing
________The life cycle of a distributed trace
________Correlating traces and logs
________Adding log entries to spans
____Instrumenting for metrics
________The life cycle of a metric
________Client/server metrics with OpenTelemetry
____Alerting on metrics abnormalities
________Adding and configuring Alertmanager
____Summary

Chapter 10: Automating Workflows with GitHub Actions
____Technical requirements
____Understanding the basics of GitHub Actions
________Exploring the components of a GitHub Action
________How to build and trigger your first GitHub Action
____Building a continuous integration workflow
________Introducing the tweeter command-line tool
________Goals of the tweeter continuous integration workflow
________Continuous integration workflow for tweeter
____Building a release workflow
________GitHub releases
________Release automation for tweeter
____Creating a custom GitHub Action using Go
________Basics of custom actions
________Goals for the tweeter custom GitHub Action
________Creating the tweeter action
____Publishing a custom Go GitHub Action
________The basics of publishing actions
________Goals for publishing the tweeter custom action
________Managing action semantic versioning
________Publishing the tweeter action to the GitHub Marketplace
____Summary

Chapter 11: Using ChatOps to Increase Efficiency
____Technical requirements
____Environment architecture
____Using an Ops service
____Building a basic chatbot
____Creating event handlers
________Case Study – Regexes versus Lexer and Parser
____Creating our Slack application
________Running the applications
____Summary

Section 3: Cloud ready Go

Chapter 12: Creating Immutable Infrastructure Using Packer
____Technical requirements
____Building an Amazon Machine Image
________Setting up an AWS source
________Defining a build block and adding some provisioners
________Executing a Packer build
____Validating images with Goss
________Creating a spec file
________Adding a Packer provisioner
____Customizing Packer with plugins
________Writing your own plugin
________Releasing a plugin
________Using our plugin in a build
________Debugging a Packer plugin
____Summary

Chapter 13: Infrastructure as Code with Terraform
____Technical requirements
____An introduction to IaC
____Understanding the basics of Terraform
________Initializing and applying infrastructure specs using Terraform
____Understanding the basics of Terraform providers
________Defining and provisioning cloud resources
____Building a pet store Terraform provider
________Resources for building custom providers
________The pet store provider
________Publishing custom providers
____Summary

Chapter 14: Deploying and Building Applications in Kubernetes
____Technical requirements
____Interacting with the Kubernetes API
________Creating a KinD cluster
________Using kubectl to interact with the API
____Deploying a load-balanced HTTP application using Go
________It all starts with main
________Creating a ClientSet
________Creating a namespace
________Deploying the application into the namespace
________Creating the NGINX deployment
________Waiting for ready replicas to match desired replicas
________Creating a Service to load-balance
________Creating an ingress to expose our application on a local host port
________Streaming pod logs for the NGINX application
____Extending Kubernetes with custom resources and operators
________Custom Resource Definitions
________Controllers
________Standing on the shoulders of giants
____Building a pet store operator
________Initializing the new operator
____Summary

Chapter 15: Programming the Cloud
____Technical requirements
____What is the cloud?
____Learning the basics of the Azure APIs
________A background on cloud APIs and SDKs
________Microsoft Azure identity, RBAC, and resource hierarchy
________Creating an Azure account and accessing the API
____Building infrastructure using Azure Resource Manager
________Azure SDK for Go
________Setting up your local environment
________Building an Azure virtual machine
____Using provisioned Azure infrastructure
________Building an Azure Storage account
____Summary

Chapter 16: Designing for Chaos
____Technical requirements
____Using overload prevention mechanisms
________Case study – AWS client requests overwhelm the network
________Using circuit breakers
________Using backoff implementations
________Combining circuit breakers with backoff
____Using rate limiters to prevent runaway workflows
________Case study – Google satellite disk erase
________Channel-based rate limiter
________Token-bucket rate limiter
____Building workflows that are repeatable and never lost
________Building idempotent workflows
________Using three-way handshakes to prevent workflow loss
____Using policies to restrict tools
________Defining a gRPC workflow service
________Creating a policy engine
________Writing a policy
________Cautions on policy engines
____Building systems with an emergency stop
________Understanding emergency stops
________Building an emergency-stop package
________Using the emergency-stop package
________Case study – Google\'s network backbone emergency stop
____Summary

Index
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