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.hadoop.hbase.ipc; import static org.apache.hadoop.hbase.ipc.CallEvent.Type.CANCELLED; import static org.apache.hadoop.hbase.ipc.CallEvent.Type.TIMEOUT; import static org.apache.hadoop.hbase.ipc.IPCUtil.setCancelled; import static org.apache.hadoop.hbase.ipc.IPCUtil.toIOE; import org.apache.hadoop.hbase.shaded.com.google.protobuf.RpcCallback; import io.netty.bootstrap.Bootstrap; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufOutputStream; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelOption; import io.netty.channel.ChannelPipeline; import io.netty.handler.codec.LengthFieldBasedFrameDecoder; import io.netty.handler.timeout.IdleStateHandler; import io.netty.util.ReferenceCountUtil; import io.netty.util.concurrent.Future; import io.netty.util.concurrent.FutureListener; import io.netty.util.concurrent.Promise; import java.io.IOException; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.ThreadLocalRandom; import java.util.concurrent.TimeUnit; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.hbase.classification.InterfaceAudience; import org.apache.hadoop.hbase.ipc.BufferCallBeforeInitHandler.BufferCallEvent; import org.apache.hadoop.hbase.ipc.HBaseRpcController.CancellationCallback; import org.apache.hadoop.hbase.shaded.protobuf.generated.RPCProtos.ConnectionHeader; import org.apache.hadoop.hbase.security.NettyHBaseSaslRpcClientHandler; import org.apache.hadoop.hbase.security.SaslChallengeDecoder; import org.apache.hadoop.hbase.security.SaslUtil.QualityOfProtection; import org.apache.hadoop.hbase.util.Threads; import org.apache.hadoop.security.UserGroupInformation; /** * RPC connection implementation based on netty. * <p> * Most operations are executed in handlers. Netty handler is always executed in the same * thread(EventLoop) so no lock is needed. */ @InterfaceAudience.Private class NettyRpcConnection extends RpcConnection { private static final Log LOG = LogFactory.getLog(NettyRpcConnection.class); private static final ScheduledExecutorService RELOGIN_EXECUTOR = Executors .newSingleThreadScheduledExecutor(Threads.newDaemonThreadFactory("Relogin")); private final NettyRpcClient rpcClient; private ByteBuf connectionHeaderPreamble; private ByteBuf connectionHeaderWithLength; @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "IS2_INCONSISTENT_SYNC", justification = "connect is also under lock as notifyOnCancel will call our action directly") private Channel channel; NettyRpcConnection(NettyRpcClient rpcClient, ConnectionId remoteId) throws IOException { super(rpcClient.conf, AbstractRpcClient.WHEEL_TIMER, remoteId, rpcClient.clusterId, rpcClient.userProvider.isHBaseSecurityEnabled(), rpcClient.codec, rpcClient.compressor); this.rpcClient = rpcClient; byte[] connectionHeaderPreamble = getConnectionHeaderPreamble(); this.connectionHeaderPreamble = Unpooled.directBuffer(connectionHeaderPreamble.length) .writeBytes(connectionHeaderPreamble); ConnectionHeader header = getConnectionHeader(); this.connectionHeaderWithLength = Unpooled.directBuffer(4 + header.getSerializedSize()); this.connectionHeaderWithLength.writeInt(header.getSerializedSize()); header.writeTo(new ByteBufOutputStream(this.connectionHeaderWithLength)); } @Override protected synchronized void callTimeout(Call call) { if (channel != null) { channel.pipeline().fireUserEventTriggered(new CallEvent(TIMEOUT, call)); } } @Override public synchronized boolean isActive() { return channel != null; } private void shutdown0() { if (channel != null) { channel.close(); channel = null; } } @Override public synchronized void shutdown() { shutdown0(); } @Override public synchronized void cleanupConnection() { if (connectionHeaderPreamble != null) { ReferenceCountUtil.safeRelease(connectionHeaderPreamble); } if (connectionHeaderWithLength != null) { ReferenceCountUtil.safeRelease(connectionHeaderWithLength); } } private void established(Channel ch) { ch.write(connectionHeaderWithLength.retainedDuplicate()); ChannelPipeline p = ch.pipeline(); String addBeforeHandler = p.context(BufferCallBeforeInitHandler.class).name(); p.addBefore(addBeforeHandler, null, new IdleStateHandler(0, rpcClient.minIdleTimeBeforeClose, 0, TimeUnit.MILLISECONDS)); p.addBefore(addBeforeHandler, null, new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4)); p.addBefore(addBeforeHandler, null, new NettyRpcDuplexHandler(this, rpcClient.cellBlockBuilder, codec, compressor)); p.fireUserEventTriggered(BufferCallEvent.success()); } private boolean reloginInProgress; private void scheduleRelogin(Throwable error) { if (error instanceof FallbackDisallowedException) { return; } synchronized (this) { if (reloginInProgress) { return; } reloginInProgress = true; RELOGIN_EXECUTOR.schedule(new Runnable() { @Override public void run() { try { if (shouldAuthenticateOverKrb()) { relogin(); } } catch (IOException e) { LOG.warn("relogin failed", e); } synchronized (this) { reloginInProgress = false; } } }, ThreadLocalRandom.current().nextInt(reloginMaxBackoff), TimeUnit.MILLISECONDS); } } private void failInit(Channel ch, IOException e) { synchronized (this) { // fail all pending calls ch.pipeline().fireUserEventTriggered(BufferCallEvent.fail(e)); shutdown0(); return; } } private void saslNegotiate(final Channel ch) { UserGroupInformation ticket = getUGI(); if (ticket == null) { failInit(ch, new FatalConnectionException("ticket/user is null")); return; } Promise<Boolean> saslPromise = ch.eventLoop().newPromise(); ChannelHandler saslHandler; try { saslHandler = new NettyHBaseSaslRpcClientHandler(saslPromise, ticket, authMethod, token, serverPrincipal, rpcClient.fallbackAllowed, this.rpcClient.conf.get("hbase.rpc.protection", QualityOfProtection.AUTHENTICATION.name().toLowerCase())); } catch (IOException e) { failInit(ch, e); return; } ch.pipeline().addFirst(new SaslChallengeDecoder(), saslHandler); saslPromise.addListener(new FutureListener<Boolean>() { @Override public void operationComplete(Future<Boolean> future) throws Exception { if (future.isSuccess()) { ChannelPipeline p = ch.pipeline(); p.remove(SaslChallengeDecoder.class); p.remove(NettyHBaseSaslRpcClientHandler.class); established(ch); } else { final Throwable error = future.cause(); scheduleRelogin(error); failInit(ch, toIOE(error)); } } }); } private void connect() { if (LOG.isDebugEnabled()) { LOG.debug("Connecting to " + remoteId.address); } this.channel = new Bootstrap().group(rpcClient.group).channel(rpcClient.channelClass) .option(ChannelOption.TCP_NODELAY, rpcClient.isTcpNoDelay()) .option(ChannelOption.SO_KEEPALIVE, rpcClient.tcpKeepAlive) .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, rpcClient.connectTO) .handler(new BufferCallBeforeInitHandler()).localAddress(rpcClient.localAddr) .remoteAddress(remoteId.address).connect().addListener(new ChannelFutureListener() { @Override public void operationComplete(ChannelFuture future) throws Exception { Channel ch = future.channel(); if (!future.isSuccess()) { failInit(ch, toIOE(future.cause())); rpcClient.failedServers.addToFailedServers(remoteId.address); return; } ch.writeAndFlush(connectionHeaderPreamble.retainedDuplicate()); if (useSasl) { saslNegotiate(ch); } else { established(ch); } } }).channel(); } @Override public synchronized void sendRequest(final Call call, HBaseRpcController hrc) throws IOException { if (reloginInProgress) { throw new IOException("Can not send request because relogin is in progress."); } hrc.notifyOnCancel(new RpcCallback<Object>() { @Override public void run(Object parameter) { setCancelled(call); synchronized (this) { if (channel != null) { channel.pipeline().fireUserEventTriggered(new CallEvent(CANCELLED, call)); } } } }, new CancellationCallback() { @Override public void run(boolean cancelled) throws IOException { if (cancelled) { setCancelled(call); } else { if (channel == null) { connect(); } scheduleTimeoutTask(call); channel.writeAndFlush(call).addListener(new ChannelFutureListener() { @Override public void operationComplete(ChannelFuture future) throws Exception { // Fail the call if we failed to write it out. This usually because the channel is // closed. This is needed because we may shutdown the channel inside event loop and // there may still be some pending calls in the event loop queue after us. if (!future.isSuccess()) { call.setException(toIOE(future.cause())); } } }); } } }); } }