Go Module Development

Basic Steps

1. Install Golang (version 1.18.6)

curl -LO https://go.dev/dl/go1.18.6.linux-amd64.tar.gz
tar -C /usr/local -xzf go1.18.6.linux-amd64.tar.gz

Add the following Go environment to .bashrc and source .bashrc to apply

export GOROOT=/usr/local/go
export GOPATH=$HOME/go
export PATH=$GOPATH/bin:$GOROOT/bin:$PATH

2. Pick a module name and create the folder by its name

E.g., module name alnair-profiler, mkdir alnair-profiler

3. Create the module

Create a go module reference.

cd alnair-profiler
go mod init alnair-profiler

4. Sample Directory Structure

Create sub-folder pkg for package source code, which can be sorted into multiple packages

Import external package, use go mod tidy automatically download the package and update the go.mod and go.sum file

Create sub-folder cmd to call the package as the main entry, reference

In this way, package and cmd can be easily extended.

alnair-profiler/
---pkg/
   ---profiler/
      server.go
---cmd/
   ---profiler/
      main.go
---go.mod
---go.sum

server.go example

package profiler

import log

func SayHi(){
    log.Println("Hi")
}

main.go example

package main
import (
    "alnair-profiler/pkg/profiler"
)

func main() {
    profiler.SayHi()
}

To run the program go run cmd/profiler/main.go. Complete example module go can be found here

5. Use VScode as IDE, SSH to a remote server

Install Go Nightly extension to enable rich language support, e.g., auto list methods of structs, check unused library, etc.

6. Kubernetes client-go example

• Connect to the cluster 1: in-cluster client configuration
• Connect to the cluster 2: out-of-cluster client configuration, download the kubeconfig file and provide absolute path to the file.

Golang Conventions

1. Callable functions outside the package starts with Capital letters. Functions started with small letters are not callable outside package.