Ejemplo n.º 1
0
func main() {
	eng := engine.New()

	c, err := net.Dial("unix", "beam.sock")
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		return
	}
	defer c.Close()
	f, err := c.(*net.UnixConn).File()
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		return
	}

	child, err := beam.FileConn(f)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		return
	}
	defer child.Close()

	sender := engine.NewSender(child)
	sender.Install(eng)

	cmd := eng.Job(os.Args[1], os.Args[2:]...)
	cmd.Stdout.Add(os.Stdout)
	cmd.Stderr.Add(os.Stderr)
	if err := cmd.Run(); err != nil {
		fmt.Fprintf(os.Stderr, "%v\n", err)
		os.Exit(1)
	}
}
Ejemplo n.º 2
0
// Spawn starts a new Engine in a child process and returns
// a proxy Engine through which it can be controlled.
//
// The commands available on the child engine are determined
// by an earlier call to Init. It is important that Init be
// called at the very beginning of the current program - this
// allows it to be called as a re-execution hook in the child
// process.
//
// Long story short, if you want to expose `myservice` in a child
// process, do this:
//
// func main() {
//     spawn.Init(myservice)
//     [..]
//     child, err := spawn.Spawn()
//     [..]
//     child.Job("dosomething").Run()
// }
func Spawn() (*engine.Engine, error) {
	if !initCalled {
		return nil, fmt.Errorf("spawn.Init must be called at the top of the main() function")
	}
	cmd := exec.Command(utils.SelfPath())
	cmd.Env = append(cmd.Env, "ENGINESPAWN=1")
	local, remote, err := beam.SocketPair()
	if err != nil {
		return nil, err
	}
	child, err := beam.FileConn(local)
	if err != nil {
		local.Close()
		remote.Close()
		return nil, err
	}
	local.Close()
	cmd.ExtraFiles = append(cmd.ExtraFiles, remote)
	// FIXME: the beam/engine glue has no way to inform the caller
	// of the child's termination. The next call will simply return
	// an error.
	if err := cmd.Start(); err != nil {
		child.Close()
		return nil, err
	}
	eng := engine.New()
	if err := engine.NewSender(child).Install(eng); err != nil {
		child.Close()
		return nil, err
	}
	return eng, nil
}