etcdhttp: non-blocking sender

etcdserver/etcdhttp/http.go

@@ -73,16 +73,23 @@ const DefaultTimeout = 500 * time.Millisecond
 func Sender(p Peers) func(msgs []raftpb.Message) {
 	return func(msgs []raftpb.Message) {
 		for _, m := range msgs {
-			// TODO: create workers that deal with message sending
+			// TODO: reuse go routines
-			// concurrently as to not block progress
+			// limit the number of outgoing connections for the same receiver
-			for {
+			go send(p, m)
+		}
+	}
+}
+
+func send(p Peers, m raftpb.Message) {
+	// TODO (xiangli): reasonable retry logic
+	for i := 0; i < 3; i++ {
 		url := p.Pick(m.To)
 		if url == "" {
 			// TODO: unknown peer id.. what do we do? I
 			// don't think his should ever happen, need to
 			// look into this further.
 			log.Println("etcdhttp: no addr for %d", m.To)
-					break
+			return
 		}
 
 		url += "/raft"
@@ -92,16 +99,13 @@ func Sender(p Peers) func(msgs []raftpb.Message) {
 		data, err := m.Marshal()
 		if err != nil {
 			log.Println("etcdhttp: dropping message:", err)
-					break // drop bad message
+			return // drop bad message
 		}
 		if httpPost(url, data) {
-					break // success
+			return // success
 		}
-
 		// TODO: backoff
 	}
-		}
-	}
 }
 
 func httpPost(url string, data []byte) bool {
@@ -111,6 +115,7 @@ func httpPost(url string, data []byte) bool {
 		elog.TODO()
 		return false
 	}
+	resp.Body.Close()
 	if resp.StatusCode != 200 {
 		elog.TODO()
 		return false