Java tutorial
/* * 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.slider.server.appmaster.rpc; import com.google.protobuf.BlockingService; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.ipc.ProtobufRpcEngine; import org.apache.hadoop.ipc.ProtocolProxy; import org.apache.hadoop.ipc.RPC; import org.apache.hadoop.ipc.RpcEngine; import org.apache.hadoop.ipc.Server; import org.apache.hadoop.net.NetUtils; import org.apache.hadoop.security.UserGroupInformation; import org.apache.hadoop.security.token.SecretManager; import org.apache.hadoop.security.token.Token; import org.apache.hadoop.security.token.TokenIdentifier; import org.apache.hadoop.yarn.api.ApplicationClientProtocol; import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationReportRequest; import org.apache.hadoop.yarn.api.records.ApplicationId; import org.apache.hadoop.yarn.api.records.ApplicationReport; import org.apache.hadoop.yarn.api.records.YarnApplicationState; import org.apache.hadoop.yarn.exceptions.YarnException; import org.apache.hadoop.yarn.security.client.ClientToAMTokenIdentifier; import org.apache.hadoop.yarn.util.ConverterUtils; import org.apache.slider.api.SliderClusterProtocol; import org.apache.slider.common.SliderExitCodes; import org.apache.slider.common.tools.Duration; import org.apache.slider.core.exceptions.BadClusterStateException; import org.apache.slider.core.exceptions.ErrorStrings; import org.apache.slider.core.exceptions.SliderException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.net.InetSocketAddress; import java.security.PrivilegedExceptionAction; public class RpcBinder { protected static final Logger log = LoggerFactory.getLogger(RpcBinder.class); public static Server createProtobufServer(InetSocketAddress addr, Configuration conf, SecretManager<? extends TokenIdentifier> secretManager, int numHandlers, BlockingService blockingService, String portRangeConfig) throws IOException { Class<SliderClusterProtocolPB> sliderClusterAPIClass = registerSliderAPI(conf); RPC.Server server = new RPC.Builder(conf).setProtocol(sliderClusterAPIClass).setInstance(blockingService) .setBindAddress(addr.getHostName()).setPort(addr.getPort()).setNumHandlers(numHandlers) .setVerbose(false).setSecretManager(secretManager).setPortRangeConfig(portRangeConfig).build(); log.debug("Adding protocol " + sliderClusterAPIClass.getCanonicalName() + " to the server"); server.addProtocol(RPC.RpcKind.RPC_PROTOCOL_BUFFER, sliderClusterAPIClass, blockingService); return server; } /** * Add the protobuf engine to the configuration. Harmless and inexpensive * if repeated * @param conf configuration to patch * @return the protocol class */ public static Class<SliderClusterProtocolPB> registerSliderAPI(Configuration conf) { Class<SliderClusterProtocolPB> sliderClusterAPIClass = SliderClusterProtocolPB.class; RPC.setProtocolEngine(conf, sliderClusterAPIClass, ProtobufRpcEngine.class); //quick sanity check here assert verifyBondedToProtobuf(conf, sliderClusterAPIClass); return sliderClusterAPIClass; } /** * Verify that the conf is set up for protobuf transport of Slider RPC * @param conf configuration * @param sliderClusterAPIClass class for the API * @return */ public static boolean verifyBondedToProtobuf(Configuration conf, Class<SliderClusterProtocolPB> sliderClusterAPIClass) { return conf.getClass("rpc.engine." + sliderClusterAPIClass.getName(), RpcEngine.class) .equals(ProtobufRpcEngine.class); } public static SliderClusterProtocol connectToServer(InetSocketAddress addr, UserGroupInformation currentUser, Configuration conf, int rpcTimeout) throws IOException { Class<SliderClusterProtocolPB> sliderClusterAPIClass = registerSliderAPI(conf); log.debug("Connecting to Slider AM at {}", addr); ProtocolProxy<SliderClusterProtocolPB> protoProxy = RPC.getProtocolProxy(sliderClusterAPIClass, 1, addr, currentUser, conf, NetUtils.getDefaultSocketFactory(conf), rpcTimeout, null); SliderClusterProtocolPB endpoint = protoProxy.getProxy(); return new SliderClusterProtocolProxy(endpoint, addr); } /** * This loops for a limited period trying to get the Proxy - * by doing so it handles AM failover * @param conf configuration to patch and use * @param rmClient client of the resource manager * @param application application to work with * @param connectTimeout timeout for the whole proxy operation to timeout * (milliseconds). Use 0 to indicate "do not attempt to wait" -fail fast. * @param rpcTimeout timeout for RPCs to block during communications * @return the proxy * @throws IOException IO problems * @throws YarnException Slider-generated exceptions related to the binding * failing. This can include the application finishing or timeouts * @throws InterruptedException if a sleep operation waiting for * the cluster to respond is interrupted. */ @SuppressWarnings("NestedAssignment") public static SliderClusterProtocol getProxy(final Configuration conf, final ApplicationClientProtocol rmClient, ApplicationReport application, final int connectTimeout, final int rpcTimeout) throws IOException, YarnException, InterruptedException { ApplicationId appId; appId = application.getApplicationId(); Duration timeout = new Duration(connectTimeout); timeout.start(); Exception exception = null; YarnApplicationState state = null; while (application != null && (state = application.getYarnApplicationState()).equals(YarnApplicationState.RUNNING)) { try { return getProxy(conf, application, rpcTimeout); } catch (IOException e) { if (connectTimeout <= 0 || timeout.getLimitExceeded()) { throw e; } exception = e; } catch (YarnException e) { if (connectTimeout <= 0 || timeout.getLimitExceeded()) { throw e; } exception = e; } //at this point: app failed to work log.debug("Could not connect to {}. Waiting for getting the latest AM address...", appId); Thread.sleep(1000); //or get the app report application = rmClient.getApplicationReport(GetApplicationReportRequest.newInstance(appId)) .getApplicationReport(); } //get here if the app is no longer running. Raise a specific //exception but init it with the previous failure throw new BadClusterStateException(exception, ErrorStrings.E_FINISHED_APPLICATION, appId, state); } public static SliderClusterProtocol getProxy(final Configuration conf, ApplicationReport application, final int rpcTimeout) throws IOException, SliderException, InterruptedException { String host = application.getHost(); int port = application.getRpcPort(); String address = host + ":" + port; if (host == null || 0 == port) { throw new SliderException(SliderExitCodes.EXIT_CONNECTIVITY_PROBLEM, "Slider instance " + application.getName() + " isn't providing a valid address for the" + " Slider RPC protocol: " + address); } UserGroupInformation currentUser = UserGroupInformation.getCurrentUser(); final UserGroupInformation newUgi = UserGroupInformation.createRemoteUser(currentUser.getUserName()); final InetSocketAddress serviceAddr = NetUtils.createSocketAddrForHost(application.getHost(), application.getRpcPort()); SliderClusterProtocol realProxy; log.debug("Connecting to {}", serviceAddr); if (UserGroupInformation.isSecurityEnabled()) { org.apache.hadoop.yarn.api.records.Token clientToAMToken = application.getClientToAMToken(); Token<ClientToAMTokenIdentifier> token = ConverterUtils.convertFromYarn(clientToAMToken, serviceAddr); newUgi.addToken(token); realProxy = newUgi.doAs(new PrivilegedExceptionAction<SliderClusterProtocol>() { @Override public SliderClusterProtocol run() throws IOException { return connectToServer(serviceAddr, newUgi, conf, rpcTimeout); } }); } else { return connectToServer(serviceAddr, newUgi, conf, rpcTimeout); } return realProxy; } }