add broker connects to filer

weed/server/filer_grpc_server.go

@@ -381,3 +381,39 @@ func (fs *FilerServer) GetFilerConfiguration(ctx context.Context, req *filer_pb.
 
 	return t, nil
 }
+
+func (fs *FilerServer) KeepConnected(stream filer_pb.SeaweedFiler_KeepConnectedServer) error {
+
+	req, err := stream.Recv()
+	if err != nil {
+		return err
+	}
+
+	clientName := fmt.Sprintf("%s:%d", req.Name, req.GrpcPort)
+	fs.brokersLock.Lock()
+	fs.brokers[clientName] = true
+	glog.V(0).Infof("+ broker %v", clientName)
+	fs.brokersLock.Unlock()
+
+	defer func() {
+		fs.brokersLock.Lock()
+		delete(fs.brokers, clientName)
+		glog.V(0).Infof("- broker %v: %v", clientName, err)
+		fs.brokersLock.Unlock()
+	}()
+
+	for {
+		if err := stream.Send(&filer_pb.KeepConnectedResponse{}); err != nil {
+			glog.V(0).Infof("send broker %v: %+v", clientName, err)
+			return err
+		}
+		// println("replied")
+
+		if _, err := stream.Recv(); err != nil {
+			glog.V(0).Infof("recv broker %v: %v", clientName, err)
+			return err
+		}
+		// println("received")
+	}
+
+}

weed/server/filer_server.go

@@ -8,9 +8,10 @@ import (
 	"sync"
 	"time"
 
-	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"google.golang.org/grpc"
 
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
+
 	"github.com/chrislusf/seaweedfs/weed/operation"
 	"github.com/chrislusf/seaweedfs/weed/pb"
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
@@ -62,6 +63,9 @@ type FilerServer struct {
 	// notifying clients
 	listenersLock sync.Mutex
 	listenersCond *sync.Cond
+
+	brokers     map[string]bool
+	brokersLock sync.Mutex
 }
 
 func NewFilerServer(defaultMux, readonlyMux *http.ServeMux, option *FilerOption) (fs *FilerServer, err error) {
@@ -69,6 +73,7 @@ func NewFilerServer(defaultMux, readonlyMux *http.ServeMux, option *FilerOption)
 	fs = &FilerServer{
 		option:         option,
 		grpcDialOption: security.LoadClientTLS(util.GetViper(), "grpc.filer"),
+		brokers:        make(map[string]bool),
 	}
 	fs.listenersCond = sync.NewCond(&fs.listenersLock)