使用 Go 管理版本

時間 2019-11-05

標籤使用管理版本简体版

原文原文鏈接

簡介

若是你曾經運行過 docker version, 就會發現它提供了不少信息:linux

PS C:\Users\tzh> docker version
Client: Docker Engine - Community
 Version:           19.03.4
 API version:       1.40
 Go version:        go1.12.10
 Git commit:        9013bf5
 Built:             Thu Oct 17 23:44:48 2019
 OS/Arch:           windows/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.4
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.10
  Git commit:       9013bf5
  Built:            Thu Oct 17 23:50:38 2019
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.2.10
  GitCommit:        b34a5c8af56e510852c35414db4c1f4fa6172339
 runc:
  Version:          1.0.0-rc8+dev
  GitCommit:        3e425f80a8c931f88e6d94a8c831b9d5aa481657
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683
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對於編譯好的二進制文件而言, 獲取版本信息是很是重要的. 儘量地提供詳細信息, 有利於後期的維護和排錯.git

如何實現

對於版本信息等, 有兩種方式, 一種從外部獲取, 好比配置文件等, 另外一種從源代碼中獲取, 將配置信息寫死在源代碼中.github

這兩種都不太好, 好比編譯時間就不太好肯定. 最好是能在 go build 時肯定這些信息.golang

幸虧, go build 提供了一個選項叫作 -ldflags '[pattern=]arg list'.web

-X importpath.name=value
	Set the value of the string variable in importpath named name to value.
	This is only effective if the variable is declared in the source code either uninitialized
	or initialized to a constant string expression. -X will not work if the initializer makes
	a function call or refers to other variables.
	Note that before Go 1.5 this option took two separate arguments.
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這使得咱們能夠在編譯生成二進制文件時, 指定某些變量的值.docker

好比咱們有個文件是 company/buildinfo 包的一部分.shell

package buildinfo

var BuildTime string
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運行 go build -ldflags="-X 'company/buildinfo.BuildTime=$(date)'" 會記錄編譯時間, 將 BuildTime 的值設置爲編譯時的時間, 即從 $(date) 中獲取的時間.express

參考:json

實踐

新增 pkg/version 包, 用於獲取版本信息.windows

package version

// 這些值應該是從外部傳入的
var (
	gitTag       string = ""
	gitCommit    string = "$Format:%H$"          // sha1 from git, output of $(git rev-parse HEAD)
	gitTreeState string = "not a git tree"       // state of git tree, either "clean" or "dirty"
	buildDate    string = "1970-01-01T00:00:00Z" // build date in ISO8601 format, output of $(date -u +'%Y-%m-%dT%H:%M:%SZ')
)
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package version

import (
	"fmt"
	"runtime"
)

// 構建時的版本信息
type VersionInfo struct {
	GitTag       string `json:"git_tag"`
	GitCommit    string `json:"git_commit"`
	GitTreeState string `json:"git_tree_state"`
	BuildDate    string `json:"build_date"`
	GoVersion    string `json:"go_version"`
	Compiler     string `json:"compiler"`
	Platform     string `json:"platform"`
}

func (info VersionInfo) String() string {
	return info.GitTag
}

func Get() VersionInfo {
	return VersionInfo{
		GitTag:       gitTag,
		GitCommit:    gitCommit,
		GitTreeState: gitTreeState,
		BuildDate:    buildDate,
		GoVersion:    runtime.Version(),
		Compiler:     runtime.Compiler,
		Platform:     fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH),
	}
}
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主要定義了一個結構體, 保持版本信息.

有些信息能夠經過 runtime 獲取, 有些是編譯時傳進來的.

這裏沒有明確的版本號, 而是使用 git tag 做爲版本標籤.

最後, 定義一個命令 version.

package cmd

import (
	"encoding/json"
	"fmt"

	"github.com/spf13/cobra"
	"tzh.com/web/pkg/version"
)

var versionCmd = &cobra.Command{
	Use:   "version",
	Short: "Print the version info of server",
	Long:  "Print the version info of server",
	Run: func(cmd *cobra.Command, args []string) {
		printVersion()
	},
}

func printVersion() {
	info := version.Get()
	infoj, err := json.MarshalIndent(&info, "", " ") // 加一點縮進
	if err != nil {
		fmt.Printf("遇到了錯誤: %v\n", err)
	}
	fmt.Println(string(infoj))
}
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別忘了使用 AddCommand 添加子命令.

// 初始化, 設置 flag 等
func init() {
	cobra.OnInitialize(initConfig)
	rootCmd.PersistentFlags().StringVarP(&cfgFile, "config", "c", "./conf/config.yaml", "config file (default: ./conf/config.yaml)")
	rootCmd.AddCommand(versionCmd)
}
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由此, 代碼基本已經改完了, 還剩下最後一點, 修改 Makefile 文件, 以便簡化操做過程.

修改 Makefile

SHELL := /bin/bash
BASEDIR = $(shell pwd)

# build with version infos
versionDir = "tzh.com/web/pkg/version"
gitTag = $(shell if [ "`git describe --tags --abbrev=0 2>/dev/null`" != "" ];then git describe --tags --abbrev=0; else git log --pretty=format:'%h' -n 1; fi)
buildDate = $(shell TZ=UTC date +%FT%T%z)
gitCommit = $(shell git log --pretty=format:'%H' -n 1)
gitTreeState = $(shell if git status|grep -q 'clean';then echo clean; else echo dirty; fi)

ldflags="-w -X ${versionDir}.gitTag=${gitTag} -X ${versionDir}.buildDate=${buildDate} -X ${versionDir}.gitCommit=${gitCommit} -X ${versionDir}.gitTreeState=${gitTreeState}"

all: gotool build
build:
	go build -ldflags ${ldflags} ./
run:
	go run -ldflags ${ldflags} ./
docker:
	go run -ldflags ${ldflags} ./ -c ./conf/config_docker.yaml
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