filer prefer volume server in same data center (#3405)

* initial prefer same data center
https://github.com/seaweedfs/seaweedfs/issues/3404

* GetDataCenter

* prefer same data center for ReplicationSource

* GetDataCenterId

* remove glog

weed/topology/data_node.go

@@ -192,6 +192,13 @@ func (dn *DataNode) GetDataCenter() *DataCenter {
 	return dcValue.(*DataCenter)
 }
 
+func (dn *DataNode) GetDataCenterId() string {
+	if dc := dn.GetDataCenter(); dc != nil {
+		return string(dc.Id())
+	}
+	return ""
+}
+
 func (dn *DataNode) GetRack() *Rack {
 	return dn.Parent().(*NodeImpl).value.(*Rack)
 }

weed/topology/topology_info.go

@@ -76,8 +76,9 @@ func (t *Topology) ToVolumeLocations() (volumeLocations []*master_pb.VolumeLocat
 			for _, d := range rack.Children() {
 				dn := d.(*DataNode)
 				volumeLocation := &master_pb.VolumeLocation{
-					Url:       dn.Url(),
-					PublicUrl: dn.PublicUrl,
+					Url:        dn.Url(),
+					PublicUrl:  dn.PublicUrl,
+					DataCenter: dn.GetDataCenterId(),
 				}
 				for _, v := range dn.GetVolumes() {
 					volumeLocation.NewVids = append(volumeLocation.NewVids, uint32(v.Id))

weed/topology/volume_growth.go

@@ -115,9 +115,10 @@ func (vg *VolumeGrowth) findAndGrow(grpcDialOption grpc.DialOption, topo *Topolo
 	if err = vg.grow(grpcDialOption, topo, vid, option, servers...); err == nil {
 		for _, server := range servers {
 			result = append(result, &master_pb.VolumeLocation{
-				Url:       server.Url(),
-				PublicUrl: server.PublicUrl,
-				NewVids:   []uint32{uint32(vid)},
+				Url:        server.Url(),
+				PublicUrl:  server.PublicUrl,
+				DataCenter: server.GetDataCenterId(),
+				NewVids:    []uint32{uint32(vid)},
 			})
 		}
 	}