Merge pull request #5374 from shykes/beam-engine

Remote communication between engines using beam

engine/engine.go

@@ -43,6 +43,7 @@ func unregister(name string) {
 // containers by executing *jobs*.
 type Engine struct {
 	handlers map[string]Handler
+	catchall Handler
 	hack     Hack // data for temporary hackery (see hack.go)
 	id       string
 	Stdout   io.Writer
@@ -60,6 +61,10 @@ func (eng *Engine) Register(name string, handler Handler) error {
 	return nil
 }
 
+func (eng *Engine) RegisterCatchall(catchall Handler) {
+	eng.catchall = catchall
+}
+
 // New initializes a new engine.
 func New() *Engine {
 	eng := &Engine{
@@ -113,10 +118,14 @@ func (eng *Engine) Job(name string, args ...string) *Job {
 	if eng.Logging {
 		job.Stderr.Add(utils.NopWriteCloser(eng.Stderr))
 	}
+	if eng.catchall != nil {
+		job.handler = eng.catchall
+	} else {
 		handler, exists := eng.handlers[name]
 		if exists {
 			job.handler = handler
 		}
+	}
 	return job
 }
 

engine/remote.go

@@ -0,0 +1,120 @@
+package engine
+
+import (
+	"fmt"
+	"github.com/dotcloud/docker/pkg/beam"
+	"github.com/dotcloud/docker/pkg/beam/data"
+	"io"
+	"os"
+	"strconv"
+	"sync"
+)
+
+type Sender struct {
+	beam.Sender
+}
+
+func NewSender(s beam.Sender) *Sender {
+	return &Sender{s}
+}
+
+func (s *Sender) Install(eng *Engine) error {
+	// FIXME: this doesn't exist yet.
+	eng.RegisterCatchall(s.Handle)
+	return nil
+}
+
+func (s *Sender) Handle(job *Job) Status {
+	msg := data.Empty().Set("cmd", append([]string{job.Name}, job.Args...)...)
+	peer, err := beam.SendConn(s, msg.Bytes())
+	if err != nil {
+		return job.Errorf("beamsend: %v", err)
+	}
+	defer peer.Close()
+	var tasks sync.WaitGroup
+	defer tasks.Wait()
+	r := beam.NewRouter(nil)
+	r.NewRoute().KeyStartsWith("cmd", "log", "stdout").HasAttachment().Handler(func(p []byte, stdout *os.File) error {
+		tasks.Add(1)
+		io.Copy(job.Stdout, stdout)
+		tasks.Done()
+		return nil
+	})
+	r.NewRoute().KeyStartsWith("cmd", "log", "stderr").HasAttachment().Handler(func(p []byte, stderr *os.File) error {
+		tasks.Add(1)
+		io.Copy(job.Stderr, stderr)
+		tasks.Done()
+		return nil
+	})
+	r.NewRoute().KeyStartsWith("cmd", "log", "stdin").HasAttachment().Handler(func(p []byte, stdin *os.File) error {
+		tasks.Add(1)
+		io.Copy(stdin, job.Stdin)
+		tasks.Done()
+		return nil
+	})
+	var status int
+	r.NewRoute().KeyStartsWith("cmd", "status").Handler(func(p []byte, f *os.File) error {
+		cmd := data.Message(p).Get("cmd")
+		if len(cmd) != 3 {
+			return fmt.Errorf("usage: %s <0-127>", cmd[0])
+		}
+		s, err := strconv.ParseUint(cmd[2], 10, 8)
+		if err != nil {
+			return fmt.Errorf("usage: %s <0-127>", cmd[0])
+		}
+		status = int(s)
+		return nil
+
+	})
+	if _, err := beam.Copy(r, peer); err != nil {
+		return job.Errorf("%v", err)
+	}
+	return Status(status)
+}
+
+type Receiver struct {
+	*Engine
+	peer beam.Receiver
+}
+
+func NewReceiver(peer beam.Receiver) *Receiver {
+	return &Receiver{Engine: New(), peer: peer}
+}
+
+func (rcv *Receiver) Run() error {
+	r := beam.NewRouter(nil)
+	r.NewRoute().KeyExists("cmd").Handler(func(p []byte, f *os.File) error {
+		// Use the attachment as a beam return channel
+		peer, err := beam.FileConn(f)
+		if err != nil {
+			f.Close()
+			return err
+		}
+		cmd := data.Message(p).Get("cmd")
+		job := rcv.Engine.Job(cmd[0], cmd[1:]...)
+		stdout, err := beam.SendPipe(peer, data.Empty().Set("cmd", "log", "stdout").Bytes())
+		if err != nil {
+			return err
+		}
+		job.Stdout.Add(stdout)
+		stderr, err := beam.SendPipe(peer, data.Empty().Set("cmd", "log", "stderr").Bytes())
+		if err != nil {
+			return err
+		}
+		job.Stderr.Add(stderr)
+		stdin, err := beam.SendPipe(peer, data.Empty().Set("cmd", "log", "stdin").Bytes())
+		if err != nil {
+			return err
+		}
+		job.Stdin.Add(stdin)
+		// ignore error because we pass the raw status
+		job.Run()
+		err = peer.Send(data.Empty().Set("cmd", "status", fmt.Sprintf("%d", job.status)).Bytes(), nil)
+		if err != nil {
+			return err
+		}
+		return nil
+	})
+	_, err := beam.Copy(r, rcv.peer)
+	return err
+}

engine/remote_test.go

@@ -0,0 +1,3 @@
+package engine
+
+import ()

engine/rengine/main.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+	"github.com/dotcloud/docker/engine"
+	"github.com/dotcloud/docker/pkg/beam"
+	"net"
+	"os"
+)
+
+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)
+	}
+}