golang以服务方式运行

golang开发的二进制程序，一般需要长期后台运行的，在linux上可以用supervisor或upstart或systemd等第三方守护进程来实现。其实golang自己也可以实现以服务的形式常驻后台。

需要的库

https://github.com/kardianos/service

这个库里面有两个接口定义，一个是：

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
}

　　

这个接口比较复杂，需要完全实现接口中的方法，还有一个比较简单的接口定义：

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
}

　　

只需要实现Start和Stop接口就行了。

一个简单的服务实例：

type program struct{}
func (p *program) Start(s service.Service) error {
    log.Println("开始服务")
    go p.run()
    return nil
}
func (p *program) Stop(s service.Service) error {
    log.Println("停止服务")
    return nil
}
func (p *program) run() {
    // 这里放置程序要执行的代码……
}

　　

之后再main方法中实现服务初始化：

func main(){
    //服务的配置信息
    cfg := &service.Config{
        Name:        "simple",
        DisplayName: "a simple service",
        Description: "This is an example Go service.",
    }
    // Interface 接口
    prg := &program{}
    // 构建服务对象
    s, err := service.New(prg, cfg)
    if err != nil {
        log.Fatal(err)
    }
    // logger 用于记录系统日志
    logger, err := s.Logger(nil)
    if err != nil {
        log.Fatal(err)
    }
    if len(os.Args) == 2 { //如果有命令则执行
        err = service.Control(s, os.Args[1])
        if err != nil {
            log.Fatal(err)
        }
    } else { //否则说明是方法启动了
        err = s.Run()
        if err != nil {
            logger.Error(err)
        }
    }
    if err != nil {
        logger.Error(err)
    }
}

　　

使用这以下参数 start, stop, restart, install, uninstall 可用于操作服务
如 :

simple  install   -- 安装服务
simple  start     -- 启动服务
simple  stop     -- 停止服务