use grpc to replace http APIs for batch volume id lookup and batch delete

1. remove batch volume id lookup http API /vol/lookup
2. remove batch delete http API /delete

weed/operation/grpc_client.go

@@ -0,0 +1,53 @@
+package operation
+
+import (
+	"fmt"
+	"strings"
+	"strconv"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
+	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+func withVolumeServerClient(volumeServer string, fn func(volume_server_pb.VolumeServerClient) error) error {
+
+	grpcAddress, err := toVolumeServerGrpcAddress(volumeServer)
+	if err != nil {
+		return err
+	}
+
+	grpcConnection, err := util.GrpcDial(grpcAddress)
+	if err != nil {
+		return fmt.Errorf("fail to dial %s: %v", grpcAddress, err)
+	}
+	defer grpcConnection.Close()
+
+	client := volume_server_pb.NewVolumeServerClient(grpcConnection)
+
+	return fn(client)
+}
+
+func toVolumeServerGrpcAddress(volumeServer string) (grpcAddress string, err error) {
+	sepIndex := strings.LastIndex(volumeServer, ":")
+	port, err := strconv.Atoi(volumeServer[sepIndex+1:])
+	if err != nil {
+		glog.Errorf("failed to parse volume server address: %v", volumeServer)
+		return "", err
+	}
+	return fmt.Sprintf("%s:%d", volumeServer[0:sepIndex], port+10000), nil
+}
+
+func withMasterServerClient(masterServer string, fn func(masterClient master_pb.SeaweedClient) error) error {
+
+	grpcConnection, err := util.GrpcDial(masterServer)
+	if err != nil {
+		return fmt.Errorf("fail to dial %s: %v", masterServer, err)
+	}
+	defer grpcConnection.Close()
+
+	client := master_pb.NewSeaweedClient(grpcConnection)
+
+	return fn(client)
+}