use fixed list of masters in both filer and volume servers

weed/filer2/filer_master.go

@@ -0,0 +1,60 @@
+package filer2
+
+import (
+	"fmt"
+	"context"
+	"time"
+
+	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"google.golang.org/grpc"
+)
+
+func (fs *Filer) GetMaster() string {
+	return fs.currentMaster
+}
+
+func (fs *Filer) KeepConnectedToMaster() {
+	glog.V(0).Infof("Filer bootstraps with masters %v", fs.masters)
+	for _, master := range fs.masters {
+		glog.V(0).Infof("Connecting to %v", master)
+		withMasterClient(master, func(client master_pb.SeaweedClient) error {
+			stream, err := client.KeepConnected(context.Background())
+			if err != nil {
+				glog.V(0).Infof("failed to keep connected to %s: %v", master, err)
+				return err
+			}
+
+			glog.V(0).Infof("Connected to %v", master)
+			fs.currentMaster = master
+
+			for {
+				time.Sleep(time.Duration(float32(10*1e3)*0.25) * time.Millisecond)
+
+				if err = stream.Send(&master_pb.Empty{}); err != nil {
+					glog.V(0).Infof("failed to send to %s: %v", master, err)
+					return err
+				}
+
+				if _, err = stream.Recv(); err != nil {
+					glog.V(0).Infof("failed to receive from %s: %v", master, err)
+					return err
+				}
+			}
+		})
+		fs.currentMaster = ""
+	}
+}
+
+func withMasterClient(master string, fn func(client master_pb.SeaweedClient) error) error {
+
+	grpcConnection, err := grpc.Dial(master, grpc.WithInsecure())
+	if err != nil {
+		return fmt.Errorf("fail to dial %s: %v", master, err)
+	}
+	defer grpcConnection.Close()
+
+	client := master_pb.NewSeaweedClient(grpcConnection)
+
+	return fn(client)
+}