messaging can compile now

weed/messaging/broker/broker_grpc_server_subscribe.go

@@ -0,0 +1,88 @@
+package broker
+
+import (
+	"io"
+	"sync"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/messaging_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+func (broker *MessageBroker) Subscribe(stream messaging_pb.SeaweedMessaging_SubscribeServer) error {
+
+	// process initial request
+	in, err := stream.Recv()
+	if err == io.EOF {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+
+	subscriberId := in.Init.SubscriberId
+
+	// get lock
+	tp := TopicPartition{
+		Namespace: in.Init.Namespace,
+		Topic:     in.Init.Topic,
+		Partition: in.Init.Partition,
+	}
+	lock := broker.topicLocks.RequestSubscriberLock(tp)
+	defer broker.topicLocks.ReleaseLock(tp, false)
+	cond := sync.NewCond(&lock.Mutex)
+
+	lastReadTime := time.Now()
+	switch in.Init.StartPosition {
+	case messaging_pb.SubscriberMessage_InitMessage_TIMESTAMP:
+		lastReadTime = time.Unix(0, in.Init.TimestampNs)
+	case messaging_pb.SubscriberMessage_InitMessage_LATEST:
+	case messaging_pb.SubscriberMessage_InitMessage_EARLIEST:
+	}
+
+	// how to process each message
+	// an error returned will end the subscription
+	eachMessageFn := func(m *messaging_pb.Message) error {
+		err := stream.Send(&messaging_pb.BrokerMessage{
+			Data:     m,
+		})
+		if err != nil {
+			glog.V(0).Infof("=> subscriber %v: %+v", subscriberId, err)
+		}
+		return err
+	}
+
+	// loop through all messages
+	for {
+
+		_, buf := lock.logBuffer.ReadFromBuffer(lastReadTime)
+
+		for pos := 0; pos+4 < len(buf); {
+
+			size := util.BytesToUint32(buf[pos : pos+4])
+			entryData := buf[pos+4 : pos+4+int(size)]
+
+			m := &messaging_pb.Message{}
+			if err = proto.Unmarshal(entryData, m); err != nil {
+				glog.Errorf("unexpected unmarshal messaging_pb.Message: %v", err)
+				pos += 4 + int(size)
+				continue
+			}
+
+			if err = eachMessageFn(m); err != nil {
+				return err
+			}
+
+			lastReadTime = time.Unix(0, m.Timestamp)
+			pos += 4 + int(size)
+		}
+
+		lock.Mutex.Lock()
+		cond.Wait()
+		lock.Mutex.Unlock()
+	}
+
+}