liubao68 commented on a change in pull request #704: [SCB-582]Provide a way to protect instance removal URL: https://github.com/apache/incubator-servicecomb-java-chassis/pull/704#discussion_r188826558
########## File path: service-registry/src/main/java/org/apache/servicecomb/serviceregistry/consumer/SimpleMicroserviceInstancePing.java ########## @@ -0,0 +1,47 @@ +/* + * 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. + */ +package org.apache.servicecomb.serviceregistry.consumer; + +import java.io.IOException; +import java.net.Socket; + +import org.apache.servicecomb.foundation.common.net.IpPort; +import org.apache.servicecomb.foundation.common.net.NetUtils; +import org.apache.servicecomb.serviceregistry.api.registry.MicroserviceInstance; + +/** + * Simple implementation of .MicroserviceInstancePing using telnet + */ +public class SimpleMicroserviceInstancePing implements MicroserviceInstancePing { + @Override + public int getOrder() { + return 100; + } + + @Override + public boolean ping(MicroserviceInstance instance) { + if (instance.getEndpoints() != null && instance.getEndpoints().size() > 0) { + IpPort ipPort = NetUtils.parseIpPortFromURI(instance.getEndpoints().get(0)); + try (Socket s = new Socket(ipPort.getHostOrIp(), ipPort.getPort())) { Review comment: I have think this problem very carefully. This mechanism only work when client get empty instances list, and we face this problem due to service center bugs, unexpected start/stop of microservices and service center, and other network failures not properly handled. In theory, these problems should be properly handled and SDK do not need to care about it, but It happens very frequently. So we add this mechanism to make SDK itself more stable in bad circumstances. Since SDK will query instances periodically, after there are instances, no problem for your mentioned scenario. And if even your scenario happens(rarely), this time, to consumer both of them are failures(no instance vs send to wrong destination). This time is very short and acceptable. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
