beam: encode Verb in an enum instead of a string

Signed-off-bu: Solomon Hykes <solomon@docker.com>

backends/backends.go

@@ -26,11 +26,11 @@ func Debug() beam.Sender {
 	backend.OnSpawn(beam.Handler(func(ctx *beam.Message) error {
 		instance := beam.NewServer()
 		instance.Catchall(beam.Handler(func(msg *beam.Message) error {
-			fmt.Printf("[DEBUG] %s %s\n", msg.Name, strings.Join(msg.Args, " "))
+			fmt.Printf("[DEBUG] %s %s\n", msg.Verb, strings.Join(msg.Args, " "))
 			ctx.Ret.Send(msg)
 			return nil
 		}))
-		_, err := ctx.Ret.Send(&beam.Message{Name: string(beam.Ack), Ret: instance})
+		_, err := ctx.Ret.Send(&beam.Message{Verb: beam.Ack, Ret: instance})
 		return err
 	}))
 	return backend
@@ -51,7 +51,7 @@ func FakeClient() beam.Sender {
 				o.Log("fake client heartbeat!")
 			}
 		})
-		_, err := ctx.Ret.Send(&beam.Message{Name: string(beam.Ack), Ret: instance})
+		_, err := ctx.Ret.Send(&beam.Message{Verb: beam.Ack, Ret: instance})
 		return err
 	}))
 	return backend

backends/simulator.go

@@ -18,7 +18,7 @@ func Simulator() beam.Sender {
 			}))
 			beam.Copy(s, in)
 		})
-		ctx.Ret.Send(&beam.Message{Name: "ack", Ret: instance})
+		ctx.Ret.Send(&beam.Message{Verb: beam.Ack, Ret: instance})
 		return nil
 	}))
 	return s

beam/beam.go

@@ -15,7 +15,7 @@ type Receiver interface {
 }
 
 type Message struct {
-	Name string
+	Verb Verb
 	Args []string
 	Att  *os.File
 	Ret  Sender
@@ -63,4 +63,4 @@ func Repeater(payload *Message) Sender {
 	})
 }
 
-var NotImplemented = Repeater(&Message{Name: "error", Args: []string{"not implemented"}})
+var NotImplemented = Repeater(&Message{Verb: Error, Args: []string{"not implemented"}})

beam/inmem_test.go

@@ -14,7 +14,8 @@ func TestInmemRetPipe(t *testing.T) {
 	defer w.Close()
 	wait := make(chan struct{})
 	go func() {
-		ret, err := w.Send(&Message{Name: "hello", Ret: RetPipe})
+		defer close(wait)
+		ret, err := w.Send(&Message{Verb: Log, Args: []string{"hello"}, Ret: RetPipe})
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -22,16 +23,18 @@ func TestInmemRetPipe(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if msg.Name != "this better not crash" {
+		if msg.Verb != Ack {
+			t.Fatalf("%#v", msg)
+		}
+		if msg.Args[0] != "this better not crash" {
 			t.Fatalf("%#v", msg)
 		}
-		close(wait)
 	}()
 	msg, err := r.Receive(Ret)
 	if err != nil {
 		t.Fatal(err)
 	}
-	if _, err := msg.Ret.Send(&Message{Name: "this better not crash"}); err != nil {
+	if _, err := msg.Ret.Send(&Message{Verb: Ack, Args: []string{"this better not crash"}}); err != nil {
 		t.Fatal(err)
 	}
 	<-wait
@@ -47,14 +50,14 @@ func TestSimpleSend(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			if msg.Name != "print" {
+			if msg.Verb != Log {
 				t.Fatalf("%#v", *msg)
 			}
 			if msg.Args[0] != "hello world" {
 				t.Fatalf("%#v", *msg)
 			}
 		}()
-		if _, err := w.Send(&Message{Name: "print", Args: []string{"hello world"}}); err != nil {
+		if _, err := w.Send(&Message{Verb: Log, Args: []string{"hello world"}}); err != nil {
 			t.Fatal(err)
 		}
 	})
@@ -116,7 +119,7 @@ func TestSendFile(t *testing.T) {
 	tmp.Seek(0, 0)
 	testutils.Timeout(t, func() {
 		go func() {
-			_, err := w.Send(&Message{Name: "file", Args: []string{"path=" + tmp.Name()}, Att: tmp})
+			_, err := w.Send(&Message{Verb: File, Args: []string{"path=" + tmp.Name()}, Att: tmp})
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -125,7 +128,7 @@ func TestSendFile(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if msg.Name != "file" {
+		if msg.Verb != File {
 			t.Fatalf("%#v", msg)
 		}
 		if msg.Args[0] != "path="+tmp.Name() {

beam/object.go

@@ -19,12 +19,12 @@ func Obj(dst Sender) *Object {
 }
 
 func (o *Object) Log(msg string, args ...interface{}) error {
-	_, err := o.Send(&Message{Name: "log", Args: []string{fmt.Sprintf(msg, args...)}})
+	_, err := o.Send(&Message{Verb: Log, Args: []string{fmt.Sprintf(msg, args...)}})
 	return err
 }
 
 func (o *Object) Ls() ([]string, error) {
-	ret, err := o.Send(&Message{Name: "ls", Ret: RetPipe})
+	ret, err := o.Send(&Message{Verb: Ls, Ret: RetPipe})
 	if err != nil {
 		return nil, err
 	}
@@ -32,20 +32,20 @@ func (o *Object) Ls() ([]string, error) {
 	if err == io.EOF {
 		return nil, fmt.Errorf("unexpected EOF")
 	}
-	if msg.Name == "set" {
+	if msg.Verb == Set {
 		if err != nil {
 			return nil, err
 		}
 		return msg.Args, nil
 	}
-	if msg.Name == "error" {
+	if msg.Verb == Error {
 		return nil, fmt.Errorf(strings.Join(msg.Args[:1], ""))
 	}
-	return nil, fmt.Errorf("unexpected verb %v", msg.Name)
+	return nil, fmt.Errorf("unexpected verb %v", msg.Verb)
 }
 
 func (o *Object) Spawn(cmd ...string) (out *Object, err error) {
-	ret, err := o.Send(&Message{Name: "spawn", Args: cmd, Ret: RetPipe})
+	ret, err := o.Send(&Message{Verb: Spawn, Args: cmd, Ret: RetPipe})
 	if err != nil {
 		return nil, err
 	}
@@ -56,18 +56,18 @@ func (o *Object) Spawn(cmd ...string) (out *Object, err error) {
 	if err != nil {
 		return nil, err
 	}
-	if msg.Name == "ack" {
+	if msg.Verb == Ack {
 		return &Object{msg.Ret}, nil
 	}
 	msg.Ret.Close()
-	if msg.Name == "error" {
+	if msg.Verb == Error {
 		return nil, fmt.Errorf("%s", strings.Join(msg.Args[:1], ""))
 	}
-	return nil, fmt.Errorf("unexpected verb %v", msg.Name)
+	return nil, fmt.Errorf("unexpected verb %v", msg.Verb)
 }
 
 func (o *Object) Attach(name string) (in Receiver, out *Object, err error) {
-	ret, err := o.Send(&Message{Name: "attach", Args: []string{name}, Ret: RetPipe})
+	ret, err := o.Send(&Message{Verb: Attach, Args: []string{name}, Ret: RetPipe})
 	if err != nil {
 		return nil, nil, err
 	}
@@ -78,23 +78,23 @@ func (o *Object) Attach(name string) (in Receiver, out *Object, err error) {
 	if err != nil {
 		return nil, nil, err
 	}
-	if msg.Name == "ack" {
+	if msg.Verb == Ack {
 		return ret, &Object{msg.Ret}, nil
 	}
 	msg.Ret.Close()
-	if msg.Name == "error" {
+	if msg.Verb == Error {
 		return nil, nil, fmt.Errorf("%s", strings.Join(msg.Args[:1], ""))
 	}
-	return nil, nil, fmt.Errorf("unexpected verb %v", msg.Name)
+	return nil, nil, fmt.Errorf("unexpected verb %v", msg.Verb)
 }
 
 func (o *Object) Error(msg string, args ...interface{}) error {
-	_, err := o.Send(&Message{Name: "error", Args: []string{fmt.Sprintf(msg, args...)}})
+	_, err := o.Send(&Message{Verb: Error, Args: []string{fmt.Sprintf(msg, args...)}})
 	return err
 }
 
 func (o *Object) Connect() (net.Conn, error) {
-	ret, err := o.Send(&Message{Name: "connect", Ret: RetPipe})
+	ret, err := o.Send(&Message{Verb: Connect, Ret: RetPipe})
 	if err != nil {
 		return nil, err
 	}
@@ -103,7 +103,7 @@ func (o *Object) Connect() (net.Conn, error) {
 	if err == io.EOF {
 		return nil, fmt.Errorf("unexpected EOF")
 	}
-	if msg.Name == "connect" {
+	if msg.Verb == Connect {
 		if msg.Att == nil {
 			return nil, fmt.Errorf("missing attachment")
 		}
@@ -115,10 +115,10 @@ func (o *Object) Connect() (net.Conn, error) {
 		msg.Att.Close()
 		return conn, nil
 	}
-	if msg.Name == "error" {
+	if msg.Verb == Error {
 		return nil, fmt.Errorf(strings.Join(msg.Args[:1], ""))
 	}
-	return nil, fmt.Errorf("unexpected verb %v", msg.Name)
+	return nil, fmt.Errorf("unexpected verb %v", msg.Verb)
 }
 
 func (o *Object) SetJson(val interface{}) error {
@@ -130,12 +130,12 @@ func (o *Object) SetJson(val interface{}) error {
 }
 
 func (o *Object) Set(vals ...string) error {
-	_, err := o.Send(&Message{Name: "set", Args: vals})
+	_, err := o.Send(&Message{Verb: Set, Args: vals})
 	return err
 }
 
 func (o *Object) Get(key string) (string, error) {
-	ret, err := o.Send(&Message{Name: "get", Args: []string{key}, Ret: RetPipe})
+	ret, err := o.Send(&Message{Verb: Get, Args: []string{key}, Ret: RetPipe})
 	if err != nil {
 		return "", err
 	}
@@ -143,7 +143,7 @@ func (o *Object) Get(key string) (string, error) {
 	if err == io.EOF {
 		return "", fmt.Errorf("unexpected EOF")
 	}
-	if msg.Name == "set" {
+	if msg.Verb == Set {
 		if err != nil {
 			return "", err
 		}
@@ -152,38 +152,38 @@ func (o *Object) Get(key string) (string, error) {
 		}
 		return msg.Args[0], nil
 	}
-	if msg.Name == "error" {
+	if msg.Verb == Error {
 		return "", fmt.Errorf(strings.Join(msg.Args[:1], ""))
 	}
-	return "", fmt.Errorf("unexpected verb %v", msg.Name)
+	return "", fmt.Errorf("unexpected verb %v", msg.Verb)
 }
 
 func (o *Object) Watch() (Receiver, error) {
-	ret, err := o.Send(&Message{Name: "watch", Ret: RetPipe})
+	ret, err := o.Send(&Message{Verb: Watch, Ret: RetPipe})
 	if err != nil {
 		return nil, err
 	}
 	msg, err := ret.Receive(0)
-	if msg.Name == "ok" {
+	if msg.Verb == Ack {
 		return ret, nil
 	}
-	if msg.Name == "error" {
+	if msg.Verb == Error {
 		return nil, fmt.Errorf(strings.Join(msg.Args[:1], ""))
 	}
-	return nil, fmt.Errorf("unexpected verb %v", msg.Name)
+	return nil, fmt.Errorf("unexpected verb %v", msg.Verb)
 }
 
 func (o *Object) Start() error {
-	ret, err := o.Send(&Message{Name: "start", Ret: RetPipe})
+	ret, err := o.Send(&Message{Verb: Start, Ret: RetPipe})
 	msg, err := ret.Receive(0)
 	if err == io.EOF {
 		return fmt.Errorf("unexpected EOF")
 	}
-	if Verb(msg.Name) == Ack {
+	if msg.Verb == Ack {
 		return nil
 	}
-	if msg.Name == "error" {
+	if msg.Verb == Error {
 		return fmt.Errorf(strings.Join(msg.Args[:1], ""))
 	}
-	return fmt.Errorf("unexpected verb %v", msg.Name)
+	return fmt.Errorf("unexpected verb %v", msg.Verb)
 }

beam/server.go

@@ -54,7 +54,7 @@ func (s *Server) OnLs(h Sender) *Server {
 }
 
 func (s *Server) Send(msg *Message) (Receiver, error) {
-	if h, exists := s.handlers[Verb(msg.Name)]; exists {
+	if h, exists := s.handlers[msg.Verb]; exists {
 		return h.Send(msg)
 	}
 	if s.catchall != nil {

beam/task.go

@@ -12,7 +12,7 @@ func Task(f func(in Receiver, out Sender)) Sender {
 	outR, outW := Pipe()
 	obj := NewServer()
 	obj.OnAttach(Handler(func(msg *Message) error {
-		msg.Ret.Send(&Message{Name: "ack", Ret: inW})
+		msg.Ret.Send(&Message{Verb: Ack, Ret: inW})
 		fmt.Printf("copying task output from %#v to %#v\n", outR, msg.Ret)
 		defer fmt.Printf("(DONE) copying task output from %#v to %#v\n", outR, msg.Ret)
 		Copy(msg.Ret, outR)
@@ -29,7 +29,7 @@ func Task(f func(in Receiver, out Sender)) Sender {
 		go f(inR, outW)
 		running = true
 		l.Unlock()
-		msg.Ret.Send(&Message{Name: "ack"})
+		msg.Ret.Send(&Message{Verb: Ack})
 		return nil
 	}))
 	return obj

beam/tree.go

@@ -16,11 +16,11 @@ func NewTree() *Tree {
 	}
 	t.OnAttach(Handler(func(msg *Message) error {
 		if len(msg.Args) == 0 || msg.Args[0] == "" {
-			msg.Ret.Send(&Message{Name: "ack", Ret: t})
+			msg.Ret.Send(&Message{Verb: Ack, Ret: t})
 			return nil
 		}
 		if child, exists := t.children[msg.Args[0]]; exists {
-			msg.Ret.Send(&Message{Name: "ack", Ret: child})
+			msg.Ret.Send(&Message{Verb: Ack, Ret: child})
 			return nil
 		}
 		Obj(msg.Ret).Error("not found")

beam/unix/conn.go

@@ -3,6 +3,7 @@ package unix
 import (
 	"fmt"
 	"os"
+	"strconv"
 
 	"github.com/docker/libswarm/beam"
 	"github.com/docker/libswarm/beam/data"
@@ -54,7 +55,7 @@ func (c *Conn) Send(msg *beam.Message) (beam.Receiver, error) {
 	if msg.Att != nil {
 		return nil, fmt.Errorf("file attachment not yet implemented in unix transport")
 	}
-	parts := []string{msg.Name}
+	parts := []string{fmt.Sprintf("%d", msg.Verb)}
 	parts = append(parts, msg.Args...)
 	b := []byte(data.EncodeList(parts))
 	// Setup nested streams
@@ -120,7 +121,11 @@ func (c *Conn) Receive(mode int) (*beam.Message, error) {
 	if len(parts) == 0 {
 		return nil, fmt.Errorf("malformed message")
 	}
-	msg := &beam.Message{Name: parts[0], Args: parts[1:]}
+	v, err := strconv.ParseUint(parts[0], 10, 32)
+	if err != nil {
+		return nil, err
+	}
+	msg := &beam.Message{Verb: beam.Verb(v), Args: parts[1:]}
 
 	// Apply mode mask
 	if fd != nil {

beam/unix/conn_test.go

@@ -15,21 +15,18 @@ func TestPair(t *testing.T) {
 	defer w.Close()
 	testutils.Timeout(t, func() {
 		go func() {
-			msg, in, out, err := r.Receive(0)
+			msg, err := r.Receive(0)
 			if err != nil {
 				t.Fatal(err)
 			}
-			if msg.Name != "print" {
+			if msg.Verb != beam.Log {
 				t.Fatalf("%#v", *msg)
 			}
 			if msg.Args[0] != "hello world" {
 				t.Fatalf("%#v", *msg)
 			}
-			if in != nil && out != nil {
-				t.Fatal("Unexpected return value")
-			}
 		}()
-		_, _, err := w.Send(&beam.Message{Name: "print", Args: []string{"hello world"}}, 0)
+		_, err := w.Send(&beam.Message{Verb: beam.Log, Args: []string{"hello world"}})
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -47,108 +44,31 @@ func TestSendReply(t *testing.T) {
 		// Send
 		go func() {
 			// Send a message with mode=R
-			in, out, err := w.Send(&beam.Message{Args: []string{"this is the request"}}, beam.R)
+			ret, err := w.Send(&beam.Message{Args: []string{"this is the request"}, Ret: beam.RetPipe})
 			if err != nil {
 				t.Fatal(err)
 			}
-			assertMode(t, in, out, beam.R)
 			// Read for a reply
-			resp, _, _, err := in.Receive(0)
+			msg, err := ret.Receive(0)
 			if err != nil {
 				t.Fatal(err)
 			}
-			if resp.Args[0] != "this is the reply" {
+			if msg.Args[0] != "this is the reply" {
-				t.Fatalf("%#v", resp)
+				t.Fatalf("%#v", msg)
 			}
 		}()
 		// Receive a message with mode=W
-		msg, in, out, err := r.Receive(beam.W)
+		msg, err := r.Receive(beam.Ret)
 		if err != nil {
 			t.Fatal(err)
 		}
 		if msg.Args[0] != "this is the request" {
 			t.Fatalf("%#v", msg)
 		}
-		assertMode(t, in, out, beam.W)
 		// Send a reply
-		_, _, err = out.Send(&beam.Message{Args: []string{"this is the reply"}}, 0)
+		_, err = msg.Ret.Send(&beam.Message{Args: []string{"this is the reply"}})
 		if err != nil {
 			t.Fatal(err)
 		}
 	})
 }
-
-func TestSendNested(t *testing.T) {
-	r, w, err := Pair()
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer r.Close()
-	defer w.Close()
-	testutils.Timeout(t, func() {
-		// Send
-		go func() {
-			// Send a message with mode=W
-			in, out, err := w.Send(&beam.Message{Args: []string{"this is the request"}}, beam.W)
-			if err != nil {
-				t.Fatal(err)
-			}
-			assertMode(t, in, out, beam.W)
-			// Send a nested message
-			_, _, err = out.Send(&beam.Message{Args: []string{"this is the nested message"}}, 0)
-			if err != nil {
-				t.Fatal(err)
-			}
-		}()
-		// Receive a message with mode=R
-		msg, in, out, err := r.Receive(beam.R)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if msg.Args[0] != "this is the request" {
-			t.Fatalf("%#v", msg)
-		}
-		assertMode(t, in, out, beam.R)
-		// Read for a nested message
-		nested, _, _, err := in.Receive(0)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if nested.Args[0] != "this is the nested message" {
-			t.Fatalf("%#v", nested)
-		}
-	})
-}
-
-// FIXME: duplicate from inmem/inmem_test.go
-// assertMode verifies that the values of r and w match
-// mode.
-// If mode has the R bit set, r must be non-nil. Otherwise it must be nil.
-// If mode has the W bit set, w must be non-nil. Otherwise it must be nil.
-//
-// If any of these conditions are not met, t.Fatal is called and the active
-// test fails.
-func assertMode(t *testing.T, r beam.Receiver, w beam.Sender, mode int) {
-	// If mode has the R bit set, r must be non-nil
-	if mode&beam.R != 0 {
-		if r == nil {
-			t.Fatalf("should be non-nil: %#v", r)
-		}
-		// Otherwise it must be nil.
-	} else {
-		if r != nil {
-			t.Fatalf("should be nil: %#v", r)
-		}
-	}
-	// If mode has the W bit set, w must be non-nil
-	if mode&beam.W != 0 {
-		if w == nil {
-			t.Fatalf("should be non-nil: %#v", w)
-		}
-		// Otherwise it must be nil.
-	} else {
-		if w != nil {
-			t.Fatalf("should be nil: %#v", w)
-		}
-	}
-}

beam/utils/queue_test.go

@@ -11,7 +11,7 @@ func TestSendRet(t *testing.T) {
 	defer w.Close()
 	q := NewQueue(w, 1)
 	defer q.Close()
-	ret, err := q.Send(&beam.Message{Name: "ping", Ret: beam.RetPipe})
+	ret, err := q.Send(&beam.Message{Verb: beam.Log, Args: []string{"ping"}, Ret: beam.RetPipe})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -20,7 +20,7 @@ func TestSendRet(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if _, err := ping.Ret.Send(&beam.Message{Name: "pong"}); err != nil {
+		if _, err := ping.Ret.Send(&beam.Message{Verb: beam.Log, Args: []string{"pong"}}); err != nil {
 			t.Fatal(err)
 		}
 	}()
@@ -28,16 +28,16 @@ func TestSendRet(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if pong.Name != "pong" {
+	if pong.Verb != beam.Log {
 		t.Fatal(err)
 	}
 }
 
 func TestSendClose(t *testing.T) {
 	q := NewQueue(beam.NopSender{}, 1)
-	q.Send(&beam.Message{Name: "hello"})
+	q.Send(&beam.Message{Verb: beam.Error, Args: []string{"hello"}})
 	q.Close()
-	if _, err := q.Send(&beam.Message{Name: "again"}); err == nil {
+	if _, err := q.Send(&beam.Message{Verb: beam.Ack, Args: []string{"again"}}); err == nil {
 		t.Fatal("send on closed queue should return an error")
 	}
 }

beam/utils/stack_test.go

@@ -20,14 +20,14 @@ func TestStackWithPipe(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			if msg.Name != "hello" {
+			if msg.Verb != beam.Log {
 				t.Fatalf("%#v", msg)
 			}
 			if strings.Join(msg.Args, " ") != "wonderful world" {
 				t.Fatalf("%#v", msg)
 			}
 		}()
-		_, err := s.Send(&beam.Message{Name: "hello", Args: []string{"wonderful", "world"}})
+		_, err := s.Send(&beam.Message{Verb: beam.Log, Args: []string{"wonderful", "world"}})
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -49,14 +49,14 @@ func TestStackWithPair(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			if msg.Name != "hello" {
+			if msg.Verb != beam.Log {
 				t.Fatalf("%#v", msg)
 			}
 			if strings.Join(msg.Args, " ") != "wonderful world" {
 				t.Fatalf("%#v", msg)
 			}
 		}()
-		_, err := s.Send(&beam.Message{Name: "hello", Args: []string{"wonderful", "world"}})
+		_, err := s.Send(&beam.Message{Verb: beam.Log, Args: []string{"wonderful", "world"}})
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -90,9 +90,9 @@ func TestStackAdd(t *testing.T) {
 	if s.Len() != 2 {
 		t.Fatalf("%#v", beforeA)
 	}
-	s.Send(&beam.Message{Name: "for b", Args: nil})
+	s.Send(&beam.Message{Verb: beam.Log, Args: []string{"for b"}})
-	beforeB.Send(&beam.Message{Name: "for a", Args: nil})
+	beforeB.Send(&beam.Message{Verb: beam.Log, Args: []string{"for a"}})
-	beforeA.Send(&beam.Message{Name: "for nobody", Args: nil})
+	beforeA.Send(&beam.Message{Verb: beam.Log, Args: []string{"for nobody"}})
 	if len(a) != 1 {
 		t.Fatalf("%#v", a)
 	}
@@ -112,7 +112,7 @@ func TestStackAddBad(t *testing.T) {
 		t.Fatalf("%#v", s)
 	}
 	r.Close()
-	if _, err := s.Send(&beam.Message{Name: "for the buffer", Args: nil}); err != nil {
+	if _, err := s.Send(&beam.Message{Verb: beam.Log, Args: []string{"for the buffer"}}); err != nil {
 		t.Fatal(err)
 	}
 	if s.Len() != 1 {
@@ -121,7 +121,7 @@ func TestStackAddBad(t *testing.T) {
 	if len(buf) != 1 {
 		t.Fatalf("%#v", buf)
 	}
-	if buf[0].Name != "for the buffer" {
+	if buf[0].Args[0] != "for the buffer" {
 		t.Fatalf("%#v", buf)
 	}
 }

beam/verbs.go

@@ -1,17 +1,19 @@
 package beam
 
-type Verb string
+type Verb uint32
 
-var (
+const (
-	Ack    Verb = "ack"
+	Ack Verb = iota
-	Log    Verb = "log"
+	Attach
-	Start  Verb = "start"
+	Connect
-	Stop   Verb = "stop"
+	Error
-	Attach Verb = "attach"
+	File
-	Spawn  Verb = "spawn"
+	Get
-	Set    Verb = "set"
+	Log
-	Get    Verb = "get"
+	Ls
-	File   Verb = "file"
+	Set
-	Error  Verb = "error"
+	Spawn
-	Ls     Verb = "ls"
+	Start
+	Stop
+	Watch
 )