A daemon package for use with Go (golang) services with no dependencies
Simplest example (just install self as daemon):
package main
import (
"fmt"
"log"
"github.com/takama/daemon"
)
func main() {
service, err := daemon.New("name", "description")
if err != nil {
log.Fatal("Error: ", err)
}
status, err := service.Install()
if err != nil {
log.Fatal(status, "\nError: ", err)
}
fmt.Println(status)
}
Real example:
// Example of a daemon with echo service
package main
import (
"fmt"
"log"
"net"
"os"
"os/signal"
"syscall"
"github.com/takama/daemon"
)
const (
// name of the service, match with executable file name
name = "myservice"
description = "My Echo Service"
// port which daemon should be listen
port = ":9977"
)
var stdlog, errlog *log.Logger
// Service has embedded daemon
type Service struct {
daemon.Daemon
}
// Manage by daemon commands or run the daemon
func (service *Service) Manage() (string, error) {
usage := "Usage: myservice install | remove | start | stop | status"
// if received any kind of command, do it
if len(os.Args) > 1 {
command := os.Args[1]
switch command {
case "install":
return service.Install()
case "remove":
return service.Remove()
case "start":
return service.Start()
case "stop":
return service.Stop()
case "status":
return service.Status()
default:
return usage, nil
}
}
// Do something, call your goroutines, etc
// Set up channel on which to send signal notifications.
// We must use a buffered channel or risk missing the signal
// if we're not ready to receive when the signal is sent.
interrupt := make(chan os.Signal, 1)
signal.Notify(interrupt, os.Interrupt, os.Kill, syscall.SIGTERM)
// Set up listener for defined host and port
listener, err := net.Listen("tcp", port)
if err != nil {
return "Possibly was a problem with the port binding", err
}
// set up channel on which to send accepted connections
listen := make(chan net.Conn, 100)
go acceptConnection(listener, listen)
// loop work cycle with accept connections or interrupt
// by system signal
for {
select {
case conn := <-listen:
go handleClient(conn)
case killSignal := <-interrupt:
stdlog.Println("Got signal:", killSignal)
stdlog.Println("Stoping listening on ", listener.Addr())
listener.Close()
if killSignal == os.Interrupt {
return "Daemon was interruped by system signal", nil
}
return "Daemon was killed", nil
}
}
// never happen, but need to complete code
return usage, nil
}
// Accept a client connection and collect it in a channel
func acceptConnection(listener net.Listener, listen chan<- net.Conn) {
for {
conn, err := listener.Accept()
if err != nil {
continue
}
listen <- conn
}
}
func handleClient(client net.Conn) {
for {
buf := make([]byte, 4096)
numbytes, err := client.Read(buf)
if numbytes == 0 || err != nil {
return
}
client.Write(buf)
}
}
func init() {
stdlog = log.New(os.Stdout, "", log.Ldate|log.Ltime)
errlog = log.New(os.Stderr, "", log.Ldate|log.Ltime)
}
func main() {
srv, err := daemon.New(name, description)
if err != nil {
errlog.Println("Error: ", err)
os.Exit(1)
}
service := &Service{srv}
status, err := service.Manage()
if err != nil {
errlog.Println(status, "\nError: ", err)
os.Exit(1)
}
fmt.Println(status)
}
All the contributors are welcome. If you would like to be the contributor please accept some rules.
- The pull requests will be accepted only in "develop" branch
- All modifications or additions should be tested
- Sorry, I'll not accept code with any dependency, only standard library
Thank you for your understanding!