「GoCN酷Go推荐」golang 跨平台部署利器

研究背景

go程序部署时，直接将编译好的文件在服务器上运行即可，一般无需安装所依赖的第三方库。

Linux下部署分为以下几种方式：

使用nohup 命令
使用 Supervisord管理
使用systemd管理

windows下部署方式：

注册成windows服务，方便进行管理

其实golang自己也可以实现以服务的形式常驻后台。

现在介绍一个包 github.com/kardianos/service ，它可以让 go 程序支持在不同系统上作为服务：注册，卸载，启动，停止。

安装部署

go get github.com/kardianos/service

使用方法

通过两个例子，我们来了解其用法。

3.1 示例程序: simple

package mainimport ("log""github.com/kardianos/service"
)var logger service.Logger //service的日志对象type program struct{} //定义结构体，并实现service.Interface的start和stop接口func (p *program) Start(s service.Service) error {// Start should not block. Do the actual work async.go p.run()return nil
}
func (p *program) run() {// Do work here
}
func (p *program) Stop(s service.Service) error {// Stop should not block. Return with a few seconds.return nil
}func main() {svcConfig := &service.Config{Name:        "GoServiceExampleSimple",DisplayName: "Go Service Example",Description: "This is an example Go service.",}prg := &program{}s, err := service.New(prg, svcConfig)if err != nil {log.Fatal(err)}logger, err = s.Logger(nil)if err != nil {log.Fatal(err)}err = s.Run()if err != nil {logger.Error(err)}
}

套路如下：

一、定义结构体program，并实现service的接口函数Start和Stop

需要实现的service接口Interface如下：

type Interface interface {// Start provides a place to initiate the service. The service doesn't// signal a completed start until after this function returns, so the// Start function must not take more then a few seconds at most.Start(s Service) error// Stop provides a place to clean up program execution before it is terminated.// It should not take more then a few seconds to execute.// Stop should not call os.Exit directly in the function.Stop(s Service) error
}

二、初始化service.Config结构体，并调用service.New创建service对象

三、为service对象设置日志Logger

四、调用service的Run方法来运行程序

3.2 示例程序2

package mainimport ("encoding/json""flag""fmt""log""os""os/exec""path/filepath""github.com/kardianos/service"
)// Config is the runner app config structure.
type Config struct {Name, DisplayName, Description stringDir  stringExec stringArgs []stringEnv  []stringStderr, Stdout string
}var logger service.Loggertype program struct {exit    chan struct{}service service.Service*Configcmd *exec.Cmd
}func (p *program) Start(s service.Service) error {// Look for exec.// Verify home directory.fullExec, err := exec.LookPath(p.Exec)if err != nil {return fmt.Errorf("Failed to find executable %q: %v", p.Exec, err)}p.cmd = exec.Command(fullExec, p.Args...)p.cmd.Dir = p.Dirp.cmd.Env = append(os.Environ(), p.Env...)go p.run()return nil
}
func (p *program) run() {logger.Info("Starting ", p.DisplayName)defer func() {if service.Interactive() {p.Stop(p.service)} else {p.service.Stop()}}()if p.Stderr != "" {f, err := os.OpenFile(p.Stderr, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0777)if err != nil {logger.Warningf("Failed to open std err %q: %v", p.Stderr, err)return}defer f.Close()p.cmd.Stderr = f}if p.Stdout != "" {f, err := os.OpenFile(p.Stdout, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0777)if err != nil {logger.Warningf("Failed to open std out %q: %v", p.Stdout, err)return}defer f.Close()p.cmd.Stdout = f}err := p.cmd.Run()if err != nil {logger.Warningf("Error running: %v", err)}return
}
func (p *program) Stop(s service.Service) error {close(p.exit)logger.Info("Stopping ", p.DisplayName)if p.cmd.Process != nil {p.cmd.Process.Kill()}if service.Interactive() {os.Exit(0)}return nil
}func getConfigPath() (string, error) {fullexecpath, err := os.Executable()if err != nil {return "", err}dir, execname := filepath.Split(fullexecpath)ext := filepath.Ext(execname)name := execname[:len(execname)-len(ext)]return filepath.Join(dir, name+".json"), nil
}func getConfig(path string) (*Config, error) {f, err := os.Open(path)if err != nil {return nil, err}defer f.Close()conf := &Config{}r := json.NewDecoder(f)err = r.Decode(&conf) //将json字符串转为Config对象if err != nil {return nil, err}return conf, nil
}func main() {svcFlag := flag.String("service", "", "Control the system service.")flag.Parse()configPath, err := getConfigPath() //获取配置文件路径if err != nil {log.Fatal(err)}config, err := getConfig(configPath) //获取配置if err != nil {log.Fatal(err)}//初始化service配置属性svcConfig := &service.Config{Name:        config.Name,DisplayName: config.DisplayName,Description: config.Description,}prg := &program{exit: make(chan struct{}),Config: config,}s, err := service.New(prg, svcConfig)if err != nil {log.Fatal(err)}prg.service = serrs := make(chan error, 5)logger, err = s.Logger(errs)if err != nil {log.Fatal(err)}go func() {for {err := <-errsif err != nil {log.Print(err)}}}()if len(*svcFlag) != 0 {//通过命令行参数来控制服务err := service.Control(s, *svcFlag)if err != nil {log.Printf("Valid actions: %q\n", service.ControlAction)log.Fatal(err)}return}err = s.Run()if err != nil {logger.Error(err)}
}

其配置文件runner.json如下

{"Name": "builder","DisplayName": "Go Builder","Description": "Run the Go Builder","Dir": "C:\\dev\\go\\src","Exec": "C:\\windows\\system32\\cmd.exe","Args": ["/C","C:\\dev\\go\\src\\all.bat"],"Env": ["PATH=C:\\TDM-GCC-64\\bin;C:\\Program Files (x86)\\Git\\cmd","GOROOT_BOOTSTRAP=C:\\dev\\go_ready","HOMEDRIVE=C:","HOMEPATH=\\Documents and Settings\\Administrator"],"Stderr": "C:\\builder_err.log","Stdout": "C:\\builder_out.log"
}

可将service相关的配置信息存储到配置文件中。通过读取配置文件中的配置信息来生成service。

接口定义（源码剖析）

这个库有两个接口

4.1 Service接口

其中Service接口有Run、Start、Stop、Restart、Install、Uninstall等核心方法可实现，以对应服务的运行、启动、停止、重启、安装、卸载操作。

type Service interface {// Run should be called shortly after the program entry point.// After Interface.Stop has finished running, Run will stop blocking.// After Run stops blocking, the program must exit shortly after.Run() error// Start signals to the OS service manager the given service should start.Start() error// Stop signals to the OS service manager the given service should stop.Stop() error// Restart signals to the OS service manager the given service should stop then start.Restart() error// Install setups up the given service in the OS service manager. This may require// greater rights. Will return an error if it is already installed.Install() error// Uninstall removes the given service from the OS service manager. This may require// greater rights. Will return an error if the service is not present.Uninstall() error// Opens and returns a system logger. If the user program is running// interactively rather then as a service, the returned logger will write to// os.Stderr. If errs is non-nil errors will be sent on errs as well as// returned from Logger's functions.Logger(errs chan<- error) (Logger, error)// SystemLogger opens and returns a system logger. If errs is non-nil errors// will be sent on errs as well as returned from Logger's functions.SystemLogger(errs chan<- error) (Logger, error)// String displays the name of the service. The display name if present,// otherwise the name.String() string
}

image-20210910150157094

其中aixService、freebsdService、solarisService、systemd、sysv、upstart、windowsService分别对应不同的操作系统aix，freebsd，solaris，linux，windows操作系统上的服务。

4.2 Interface接口

Interface接口中有Start和Stop

type Interface interface {// Start provides a place to initiate the service. The service doesn't not// signal a completed start until after this function returns, so the// Start function must not take more then a few seconds at most.Start(s Service) error// Stop provides a place to clean up program execution before it is terminated.// It should not take more then a few seconds to execute.// Stop should not call os.Exit directly in the function.Stop(s Service) error
}

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