Golang anatomy
From wikinotes
This page is a general getting started in go.
Project Structure
myproject/ go.mod # module name, requirements main.go # 'main' package's 'main()' function is optional CLI entrypoint printer.go # other 'main' package src are in toplevel dir internal/ # exported symbols from internal packages are only exposed within 'myproject' logger/ # subpackage logger.go math/ # subpackage division.go multiplication.gomyproject/go.mod
// myproject/go.mod module example.com/x/myproject go 1.18myproject/main.go
// myproject/main.go package main import ( "fmt" "os" "example.com/x/myproject/internal/logger" ) ErrEnvVarUnset = errors.New("Environment Variable Not Set") func getUserName() (name string, err error) { username := os.Getenv("USER") if username == "" { return nil, ErrEnvVarUnset; } return username, nil; } func main() { logger.Info.Println("a log statement"); name, err := getUserName(); // type inference if err != nil { panic(err); } var gid int16; // declare var gid = 1000; // assign typed var fmt.Printf("logged in as user: %s, with gid %i", name, gid); }myproject/internal/logger/logger.go
// myproject/internal/logger/logger.go package logger var Info *log.Logger func init() { Info = log.New(io.Stderr, "INFO: ", log.Ldate|log.Ltime|log.Llongfile) }
Tools
# project management go mod init foo.net/x/my-project # create new project $GOPRIVATE # glob-matches projects not published to public registry # requirements go get example.com/module@latest # add/update requirement (latest) go get example.com/module v1.1.1 # add/update/downgrade to target version # package management go install example.com/module@latest # install tool # documentation go doc io # functions/constants on 'io' go doc io.File # methods on 'io.File' # build/run main package go run . # test # build management go build go clean go install