blocking on GRAB_JOB instead of executing blocked

worker/worker.go

@@ -12,6 +12,9 @@ import (
 )
 
 const (
+	Unlimited = 0
+	OneByOne  = 1
+
 	Immediately = 0
 )
 
@@ -19,7 +22,7 @@ const (
 Worker side api for gearman
 
 usage:
-w = worker.New()
+w = worker.New(worker.Unlimited)
 w.AddFunction("foobar", foobar)
 w.AddServer("127.0.0.1:4730")
 w.Work() // Enter the worker's main loop
@@ -34,6 +37,7 @@ func foobar(job *Job) (data []byte, err os.Error) {
 }
 */
 type Worker struct {
+	sync.Mutex
 	agents  []*agent
 	funcs   JobFuncs
 	in      chan *inPack
@@ -43,16 +47,19 @@ type Worker struct {
 	// assign a ErrFunc to handle errors
 	ErrorHandler ErrorHandler
 	JobHandler   JobHandler
-	mutex        sync.Mutex
+	limit        chan bool
 }
 
 // Get a new worker
-func New() (worker *Worker) {
+func New(limit int) (worker *Worker) {
 	worker = &Worker{
 		agents: make([]*agent, 0),
 		funcs:  make(JobFuncs),
 		in:     make(chan *inPack, QUEUE_SIZE),
 	}
+	if limit != Unlimited {
+		worker.limit = make(chan bool, limit - 1)
+	}
 	return
 }
 
@@ -89,8 +96,8 @@ func (worker *Worker) broadcast(outpack *outPack) {
 // The API will tell every connected job server that 'I can do this'
 func (worker *Worker) AddFunc(funcname string,
 	f JobFunc, timeout uint32) (err error) {
-	worker.mutex.Lock()
-	defer worker.mutex.Unlock()
+	worker.Lock()
+	defer worker.Unlock()
 	if _, ok := worker.funcs[funcname]; ok {
 		return fmt.Errorf("The function already exists: %s", funcname)
 	}
@@ -120,8 +127,8 @@ func (worker *Worker) addFunc(funcname string, timeout uint32) {
 
 // Remove a function.
 func (worker *Worker) RemoveFunc(funcname string) (err error) {
-	worker.mutex.Lock()
-	defer worker.mutex.Unlock()
+	worker.Lock()
+	defer worker.Unlock()
 	if _, ok := worker.funcs[funcname]; !ok {
 		return fmt.Errorf("The function does not exist: %s", funcname)
 	}
@@ -149,9 +156,17 @@ func (worker *Worker) handleInPack(inpack *inPack) {
 	case ERROR:
 		worker.err(GetError(inpack.data))
 	case JOB_ASSIGN, JOB_ASSIGN_UNIQ:
+		go func() {
 			if err := worker.exec(inpack); err != nil {
 				worker.err(err)
 			}
+		}()
+		if (worker.limit != nil) {
+			worker.limit <- true
+		}
+		inpack.a.Grab()
+	case ECHO_RES:
+		fallthrough
 	default:
 		worker.customeHandler(inpack)
 	}
@@ -177,7 +192,7 @@ func (worker *Worker) Work() {
 	}
 	var inpack *inPack
 	for inpack = range worker.in {
-		go worker.handleInPack(inpack)
+		worker.handleInPack(inpack)
 	}
 }
 
@@ -225,6 +240,9 @@ func (worker *Worker) SetId(id string) {
 // Execute the job. And send back the result.
 func (worker *Worker) exec(inpack *inPack) (err error) {
 	defer func() {
+		if (worker.limit != nil) {
+			<-worker.limit
+		}
 		if r := recover(); r != nil {
 			if e, ok := r.(error); ok {
 				err = e
@@ -259,7 +277,6 @@ func (worker *Worker) exec(inpack *inPack) (err error) {
 		outpack.handle = inpack.handle
 		outpack.data = r.data
 		inpack.a.write(outpack)
-		inpack.a.Grab()
 	}
 	return
 }