详解如何在Go项目中输出版本信息

➜ ~ docker version
Client: Docker Engine - Community
 Version:   18.09.2
 API version:  1.39
 Go version:  go1.10.8
 Git commit:  6247962
 Built:    Sun Feb 10 04:12:39 2019
 OS/Arch:   darwin/amd64
 Experimental:  false
➜ ~

package main

import (
 "flag"
 "fmt"
 "os"
)

//需要赋值的变量
var version = ""

//通过flag包设置-version参数
var printVersion bool

func init() {
 flag.BoolVar(&printVersion, "version", false, "print program build version")
 flag.Parse()
}

func main() {
 if printVersion {
  println(version)
  os.Exit(0)
 }
 fmt.Printf("example for print version")
}

go build -ldflags "-X main.version=v0.1" -o example

➜ ./example
version=v0.1

-ldflags '[pattern=]arg list'
 arguments to pass on each go tool link invocation.

-X importpath.name=value
 Set the value of the string variable in importpath named name to value.
 Note that before Go 1.5 this option took two separate arguments.
 Now it takes one argument split on the first = sign.

package main

import (
  "flag"

  "github.com/go-demo/version"
)

//通过flag包设置-version参数
var printVersion bool

func init() {
  flag.BoolVar(&printVersion, "version", false, "print program build version")
  flag.Parse()
}

func main() {
  if printVersion {
    version.PrintVersion()
  }
}

#!/bin/sh
version="v0.1"
path="github.com/go-demo/version"
flags="-X $path.Version=$version -X '$path.GoVersion=$(go version)' -X '$path.BuildTime=`date +"%Y-%m-%d %H:%m:%S"`' -X $path.GitCommit=`git rev-parse HEAD`"
go build -ldflags "$flags" -o example example-version.go

➜ sh build.sh
➜ ./example -version
Version: v0.1
Go Version: go version go1.13.1 darwin/amd64
Git Commit: a775ecd27c5e78437b605c438905e9cc888fbc1c
Build Time: 2020-01-09 19:01:51