Add ping service.

common/common.proto

@@ -40,3 +40,12 @@ enum DetectPoint {
     server = 1;
     proxy = 2;
 }
+
+meesage Commands {
+    repeated Command commands = 1;
+}
+
+message Command {
+    string command = 1;
+    repeated KeyStringValuePair args = 2;
+}

register/InstancePing.proto

+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.register";
+option csharp_namespace = "SkyWalking.NetworkProtocol";
+
+import "common/common.proto";
+
+service ServiceInstancePing {
+    rpc doPing (ServiceInstancePingPkg) returns (Commands) {
+    }
+}
+
+message ServiceInstancePingPkg {
+    int32 serviceInstanceId = 1;
+    int64 time = 2;
+}

register/Register.proto

@@ -62,8 +62,9 @@ message ServiceInstances {
 message ServiceInstance {
     int32 serviceId = 1;
     string instanceUUID = 2;
-    repeated KeyStringValuePair tags = 3;
-    repeated KeyStringValuePair properties = 4;
+    int64 time = 3;
+    repeated KeyStringValuePair tags = 4;
+    repeated KeyStringValuePair properties = 5;
 }
 
 message ServiceInstanceRegisterMapping {