GoLang

Guide to setup golang development environment on MacOS without admin privileges

You can use either JetBrains GoLand or VSCode as your go IDE.

Recommended tools/libs for Go projects:

Tools

1. GoReleaser - Cross-compile and Release to GitHub

2. protobuf - gRPC code gen tool and serialization library

3. ko - Build, sign and publish OCI images from source code.

Libraries

1. testify - Unit and integration testing

2. mockery - generate mocks for golang interfaces

3. entgo - An entity framework for Go

Install

brew install go
# verify 
go version                                                                                                                                                                          ☸ rancher-desktop on ☁️  
# go version go1.21.1 darwin/arm64

Multiple go versions

If you need multiple versions for testing...

brew install go@1.19
# brew switch
brew unlink go
brew link go@1.19
# back to 1.21
brew unlink go
brew link  go

Optional tools for GoLang Developers

# buf: proto tool https://buf.build/docs/tour-1
brew install bufbuild/buf/buf
# protobuf
brew install protobuf
# grpc cli client
brew install grpcurl
# postman is a UI client for gRPC (optional)
brew install --cask --appdir=~/Applications postman
# certs for mTLS
brew install step

## build & deploy
# ko is a tool for build/publish/deploy container images  for Go applications
brew install ko
brew install goreleaser
brew install skaffold
brew tap anchore/syft
brew install syft
brew install cosign

# Update outdated Go dependencies interactively
# Usage: go-mod-upgrade ./...
go install github.com/oligot/go-mod-upgrade@latest
# for static check/linter
go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
# mockery
go install github.com/vektra/mockery/v2@latest
# linter and tool for proto files
# *** (if you use brew to install buf, skip next line) ***
go install github.com/bufbuild/buf/cmd/buf@latest

# Install protoc plugins
go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
go install github.com/srikrsna/protoc-gen-gotag@latest
go install entgo.io/contrib/entproto/cmd/protoc-gen-entgrpc@latest

# Installing PGV can currently only be done from source: 
# from user's home directory, run
go get -d github.com/envoyproxy/protoc-gen-validate
cd ~/go/src/github.com/envoyproxy/protoc-gen-validate
git pull
make build

Make sure you have following in your ~/my/paths.zsh

# Executable scripts from GoLang packages you install will be put in here
export PATH=$PATH:$(go env GOPATH)/bin

for complete project example with VSCode settings, refer hello project

Workspace

~/go/bin, ~/go/pkg, ~/go/src are created automatically when you pull your first dependency.

Project

Your first project

create a project directory outside your GOPATH:

mkdir  -p ~/Developer/Work/go/hello

Initialize module

this will create go.mod file

cd ~/Developer/Work/go/hello

go mod init github.com/xmlking/hello

Write your code

$ cat <<EOF > hello.go
package main

import (
    "fmt"
    "rsc.io/quote"
)

func main() {
    fmt.Println(quote.Hello())
}
EOF

Build and Run

go build
# run
./hello
#  ./... pattern matches all the packages within the current module.
go build ./...

Note: The go.mod file was updated to include explicit versions for your dependencies In contrast, go build and go test will not remove dependencies from go.mod that are no longer required and only update go.mod based on the current build invocation's tags/OS/architecture.

Test

# test all the go files within the current directory
go test
# test all the packages within the current module
go test ./...
# tests for your module plus the tests for all direct and indirect dependencies to check for incompatibilities
go test all

Install

this will copy binary into $GOPATH/bin i.e., ~/go/bin

go install 

Release

recomdned steps for releasing modules

# to possibly prune any extraneous requirements
go mod tidy
#  test and  validate your module
go test all

Ensure your go.sum file is committed along with your go.mod file.

A new module version may be published by pushing a tag to the repository that contains the module source code.

Docs

# read docs
go doc rsc.io/quote
go help build

Format

format your source code with prettier or fmt

go fmt hello.go

Daily Workflow

Note there was no go get required in the example above.

Your typical day-to-day workflow can be:

• Add import statements to your .go code as needed.

• Standard commands like go build or go test will automatically add new dependencies as needed to satisfy imports (updating go.mod and downloading the new dependencies).

• When needed, more specific versions of dependencies can be chosen with commands such as go get foo@v1.2.3, go get foo@master, go get foo@e3702bed2, or by editing go.mod directly.

---

Go Commands

go env
#  View final versions that will be used in a build
go list -m all
#  View available minor and patch upgrades for all direct and indirect dependencies
go list -u -m all
#  List the available tagged versions of that module
go list -m -versions rsc.io/sampler
#  Update all direct and indirect dependencies to latest minor or patch upgrades
go get -u  # to use the latest minor or patch releases
go get -u=patch # to use the latest patch releases
#  Updates to the latest version of `foo` plus direct and indirect dependencies of `foo`
go get foo  # is equivalent to `go get foo@latest`
go get -u foo # solely gets the latest version of `foo`
#  Build or test all packages in the module when run from the module root directory
go build ./...
go test ./...
# lists all the commands go build invokes.
go build -x

go test -v context
go test -race
#  Prune any no-longer-needed dependencies from go.mod and add any dependencies needed
go mod tidy
#  If you are curious why a particular module is showing up in your go.mod, then run
go mod why -m <module>
#  Optional step to create a vendor directory (use special case only)
#  Go modules ignores the vendor/ directory by default. The idea is to eventually do away with vendoring
go mod vendor

Points

• A repository contains one or more Go modules.

• Each module contains one or more Go packages.

• Each package consists of one or more Go source files in a single directory.

• A module is defined by a tree of Go source files with a go.mod file in the tree's root directory.

• The import paths for all packages in a module share the module path as a common prefix.

• The module path and the relative path from the go.mod to a package's directory together determine a package's import path.

---

FAQ

What go build do?

What the go command does depends on whether we run it for a "normal" package or for the special "main" package.

For packages

• go build builds your package then discards the results.

• go install builds then installs the package in your $GOPATH/pkg directory.

For commands (package main)

• go build builds the command and leaves the result in the current working directory.

• go install builds the command in a temporary directory then moves it to $GOPATH/bin.

Basically you can use go build as a check that the packages can be built (along with their dependencies) while go install also (permanently) installs the results in the proper folders of your $GOPATH.

It is also worth noting that starting with Go 1.5 go install also removes executables created by go build

How to cross Compiling on MacOS For Linux runtime?

brew install FiloSottile/musl-cross/musl-cross

CGO_ENABLED=1 CC=x86_64-linux-musl-gcc CXX=x86_64-linux-musl-g++ \
ko resolve -P -f deploy/ > release.yaml

---

Learning

1. Signup for https://golangweekly.com/

2. Data Journey with Golang, GraphQL and Microservices. Ref: YouTube talks about BigTable --> Data Microservices (Go-Micro) --> GraphQL Gateway-gqlgen (ACL check permission at field level, codegen)

3. Interfaces , genarics (concrete types vs abstract types). Ref: YouTube Lessons Learned: "Always Return Concrete types, receive interfaces as perameters"

4. Heap vs Stack memory. Ref: YouTube Are pointers a performance optimization? Ref: medium

---

Reference

1. https://github.com/golang/go/wiki/Modules

2. https://blog.golang.org/using-go-modules

3. Project Layout

   1. https://github.com/golang-standards/project-layout

   2. https://code.fb.com/security/service-encryption/

4. https://medium.com/@amsokol.com/tutorial-how-to-develop-go-grpc-microservice-with-http-rest-endpoint-middleware-kubernetes-daebb36a97e9

5. goreleaser supply-chain-example