golang

Golang Learning resources

Software engineering is a craft that should be honed, debated, and continuously improved.

Golang Installation or Upgradation

go version
which go

wget https://go.dev/dl/go1.17.7.linux-amd64.tar.gz

sudo rm -rf /usr/local/go

sudo tar -xzf go1.17.7.linux-amd64.tar.gz

sudo mv go /usr/local

export PATH=$PATH:/usr/local/go/bin

source $HOME/.profile

go version

Data type detection

dataFields interface{}

dtype := reflect.TypeOf(dataFields).Kind().String()

var c Company

fmt.Println(reflect.ValueOf(&c).Kind().String()) //ptr
fmt.Println(reflect.ValueOf([]string{"aid", "cid", "type"}).Kind().String()) //slice

How to get the name of a struct?

func structName(myvar interface{}) string {
	if t := reflect.TypeOf(myvar); t.Kind() == reflect.Ptr {
		return t.Elem().Name()
	} else {
		return t.Name()
	}
}

type Achead struct{
 ID int
 Code string
}

fmt.Println(structName(Achead{}))
fmt.Println(structName(&Achead{})) //Achead

Linux terminal build for windows

Syntax: env GOOS=target-OS GOARCH=target-architecture go build package-import-path
$ env GOOS=windows go build

Windows terminal build

set GOOS=linux
go build -o appName

Windows powershell build

If you're using PowerShell, then changing values of environment variables should be done like: $Env:<variable-name> = "<new-value>"

$Env:GOOS = "linux"; $Env:GOARCH = "amd64"; go build -o hello

$Env:GOOS="linux";$Env:GOARCH="amd64"; go build -ldflags '-w -s'

Cache clean command

go clean --cache

Trouble-shooting

Cleaning the go caches once fixed some “unknown import path”/“cannot find module providing package” errors

go clean -cache -modcache -i -r

Testing command

$Env:GOOS="windows";go test .\utility\

$Env:GOOS="windows";go test -timeout 30s -run ^TestSsPLNT$ graphmysql/utility

$Env:GOOS="windows";go test ./...

Golang How to upgrade to Go 1.17

go mod tidy -go=1.17 go mod edit -go 1.20

Module on by default

go env -w GO111MODULE=auto

fmt.Println("NumGoroutine:", runtime.NumGoroutine())
GODEBUG=gctrace=1 ./chaldal

Go Module Create

mkdir encdec && cd encdec
go mod init mateors.com/encdec
write your source code & save the file

This command deletes the cache downloaded along with unpacked code dependencies

go clean -modcache

Go Module, Call your code from anothe module

import (
     ...
    "mateors.com/encdec"
)

go mod edit -replace mateors.com/encdec=../encdec
go get mateors.com/encdec

Resource

• https://golang.org/doc/tutorial/call-module-code
• https://go.dev/blog/go116-module-changes
• https://maelvls.dev/go111module-everywhere/
• https://hasura.io/graphql/database/
• https://nats.io/
• https://github.com/hasura/graphql-engine
• https://hasura.io/graphql/database/
• https://lecstor.com/go-cheatsheet
• https://github.com/boyter/scc