service

go-spfc

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A lib for wrapping services in Linux (Upstart or systemd) and MacOS (launchd).

Installing

1. With go get: go get github.com/franciscocpg/go-spfc
2. Or, the best way, using some dependency manager like glide

Using

Supposing you have a mongodb service installed in a CentOS (running systemd) or Ubuntu (running systemd or upstart) or MacOS (running launchd) machine you can instantiate a new handler this way:

 package main

import (
	"fmt"
	"github.com/franciscocpg/go-spfc"
)

func main() {
	h := service.NewHandler("mongod")
	st, err := h.Start()
	errorHandler(err)
	printStatus(st)
	st, err = h.GetStatus()
	errorHandler(err)
	printStatus(st)
	st, err = h.Stop()
	errorHandler(err)
	printStatus(st)
}

func printStatus(st service.Status) {
	fmt.Printf("Running: %t, st.PID: %d\n", st.Running, st.PID)
}

func errorHandler(err error) {
	if err != nil {
		panic(err)
	}
}

result

Running: true, st.PID: 3765
Running: true, st.PID: 3765
Running: false, st.PID: 0

Wait service to start or stop

Especially when you are using a Mac the previous code can result something like this

Running: false, st.PID: 0
Running: false, st.PID: 0
Running: false, st.PID: 0

What happens? The problem is that launchd runs commands in a asynchronous way, so when we get the status, the service was not started (or stopped) yet. To workaround this just wait the service start or stop this way

package main

import (
	"fmt"t
	"github.com/franciscocpg/go-spfc"
	"time"
)

func main() {
	timeout := 10 * time.Second
	h := service.NewHandler("mongod")
	st, err := h.StartAndWait(timeout)
	errorHandler(err)
	printStatus(st)
	st, err = h.GetStatus()
	errorHandler(err)
	printStatus(st)
	st, err = h.StopAndWait(timeout)
	errorHandler(err)
	printStatus(st)
}

func printStatus(st service.Status) {
	fmt.Printf("Running: %t, st.PID: %d\n", st.Running, st.PID)
}

func errorHandler(err error) {
	if err != nil {
		panic(err)
	}
}

If someting goes wrong, the err is populate with a timeout message.

TODO

• Implement the systemd communication using DBUS (go-systemd) instead of a process call to systemctl.