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package org.apache.helix.ipc.netty;
/*
* 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.
*/
import io.netty.bootstrap.Bootstrap;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.CompositeByteBuf;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.helix.ipc.HelixIPCCallback;
import org.apache.helix.ipc.HelixIPCService;
import org.apache.helix.resolver.HelixAddress;
import org.apache.helix.resolver.HelixMessageScope;
import org.apache.log4j.Logger;
import com.codahale.metrics.Counter;
import com.codahale.metrics.JmxReporter;
import com.codahale.metrics.Meter;
import com.codahale.metrics.MetricRegistry;
/**
* Provides partition/state-level messaging among nodes in a Helix cluster.
*
* The message format is (where len == 4B, and contains the length of the next field)
*
*
* +----------------------+
* | totalLength (4B) |
* +----------------------+
* | version (4B) |
* +----------------------+
* | messageType (4B) |
* +----------------------+
* | messageId (16B) |
* +----------------------+
* | len | cluster |
* +----------------------+
* | len | resource |
* +----------------------+
* | len | partition |
* +----------------------+
* | len | state |
* +----------------------+
* | len | srcInstance |
* +----------------------+
* | len | dstInstance |
* +----------------------+
* | len | message |
* +----------------------+
*
*
*
*/
public class NettyHelixIPCService implements HelixIPCService {
private static final Logger LOG = Logger.getLogger(NettyHelixIPCService.class);
private static final int MESSAGE_VERSION = 1;
// Parameters for length header field of message (tells decoder to interpret but preserve length
// field in message)
private static final int MAX_FRAME_LENGTH = 1024 * 1024;
private static final int LENGTH_FIELD_OFFSET = 0;
private static final int LENGTH_FIELD_LENGTH = 4;
private static final int LENGTH_ADJUSTMENT = -4;
private static final int INITIAL_BYTES_TO_STRIP = 0;
private static final int NUM_LENGTH_FIELDS = 7;
private final Config config;
private final AtomicBoolean isShutdown;
private final Map> channelMap;
private final ConcurrentMap channelOpenTimes;
private final MetricRegistry metricRegistry;
private final ConcurrentMap callbacks;
private EventLoopGroup eventLoopGroup;
private Bootstrap clientBootstrap;
private Meter statTxMsg;
private Meter statRxMsg;
private Meter statTxBytes;
private Meter statRxBytes;
private Counter statChannelOpen;
private Counter statError;
private JmxReporter jmxReporter;
public NettyHelixIPCService(Config config) {
super();
this.config = config;
this.isShutdown = new AtomicBoolean(true);
this.channelMap = new HashMap>();
this.channelOpenTimes = new ConcurrentHashMap();
this.metricRegistry = new MetricRegistry();
this.callbacks = new ConcurrentHashMap();
}
/**
* Starts message handling server, creates client bootstrap, and bootstraps partition routing
* table.
*/
public void start() throws Exception {
if (isShutdown.getAndSet(false)) {
eventLoopGroup = new NioEventLoopGroup();
statTxMsg = metricRegistry.meter(MetricRegistry.name(NettyHelixIPCService.class, "txMsg"));
statRxMsg = metricRegistry.meter(MetricRegistry.name(NettyHelixIPCService.class, "rxMsg"));
statTxBytes =
metricRegistry.meter(MetricRegistry.name(NettyHelixIPCService.class, "txBytes"));
statRxBytes =
metricRegistry.meter(MetricRegistry.name(NettyHelixIPCService.class, "rxBytes"));
statChannelOpen =
metricRegistry.counter(MetricRegistry.name(NettyHelixIPCService.class, "channelOpen"));
statError = metricRegistry.counter(MetricRegistry.name(NettyHelixIPCService.class, "error"));
// Report metrics via JMX
jmxReporter = JmxReporter.forRegistry(metricRegistry).build();
jmxReporter.start();
new ServerBootstrap().group(eventLoopGroup).channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_KEEPALIVE, true).childOption(ChannelOption.SO_KEEPALIVE, true)
.childHandler(new ChannelInitializer() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(
new LengthFieldBasedFrameDecoder(MAX_FRAME_LENGTH, LENGTH_FIELD_OFFSET,
LENGTH_FIELD_LENGTH, LENGTH_ADJUSTMENT, INITIAL_BYTES_TO_STRIP));
socketChannel.pipeline().addLast(new HelixIPCCallbackHandler());
}
}).bind(new InetSocketAddress(config.getPort()));
clientBootstrap =
new Bootstrap().group(eventLoopGroup).channel(NioSocketChannel.class)
.option(ChannelOption.SO_KEEPALIVE, true)
.handler(new ChannelInitializer() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(
new LengthFieldPrepender(LENGTH_FIELD_LENGTH, true));
}
});
}
}
/**
* Shuts down event loops for message handling server and message passing client.
*/
public void shutdown() throws Exception {
if (!isShutdown.getAndSet(true)) {
jmxReporter.stop();
eventLoopGroup.shutdownGracefully();
}
}
/**
* Sends a message to all partitions with a given state in the cluster.
*/
@Override
public void send(HelixAddress destination, int messageType, UUID messageId, ByteBuf message) {
// Send message
try {
// Get list of channels
List channels = channelMap.get(destination.getSocketAddress());
if (channels == null) {
synchronized (channelMap) {
channels = channelMap.get(destination.getSocketAddress());
if (channels == null) {
channels = new ArrayList(config.getNumConnections());
for (int i = 0; i < config.getNumConnections(); i++) {
channels.add(null);
}
channelMap.put(destination.getSocketAddress(), channels);
}
}
}
// Pick the channel for this scope
int idx = (Integer.MAX_VALUE & destination.getScope().hashCode()) % channels.size();
Channel channel = channels.get(idx);
if (channel == null || !channel.isOpen() || isExpired(channel)) {
synchronized (channelMap) {
channel = channels.get(idx);
if (channel == null || !channel.isOpen() || isExpired(channel)) {
if (channel != null && channel.isOpen()) {
channel.close();
}
channel = clientBootstrap.connect(destination.getSocketAddress()).sync().channel();
channels.set(idx, channel);
statChannelOpen.inc();
channelOpenTimes.put(channel, System.currentTimeMillis());
}
}
}
// Compute total length
int headerLength =
NUM_LENGTH_FIELDS
* (Integer.SIZE / 8)
+ (Integer.SIZE / 8)
* 2 // version, type
+ (Long.SIZE / 8)
* 2 // 128 bit UUID
+ getLength(destination.getScope().getCluster())
+ getLength(destination.getScope().getResource())
+ getLength(destination.getScope().getPartition())
+ getLength(destination.getScope().getState()) + getLength(config.getInstanceName())
+ getLength(destination.getInstanceName());
int messageLength = message == null ? 0 : message.readableBytes();
// Build message header
ByteBuf headerBuf = channel.alloc().buffer(headerLength);
headerBuf.writeInt(MESSAGE_VERSION).writeInt(messageType)
.writeLong(messageId.getMostSignificantBits())
.writeLong(messageId.getLeastSignificantBits());
writeStringWithLength(headerBuf, destination.getScope().getCluster());
writeStringWithLength(headerBuf, destination.getScope().getResource());
writeStringWithLength(headerBuf, destination.getScope().getPartition());
writeStringWithLength(headerBuf, destination.getScope().getState());
writeStringWithLength(headerBuf, config.getInstanceName());
writeStringWithLength(headerBuf, destination.getInstanceName());
// Compose message header and payload
headerBuf.writeInt(messageLength);
CompositeByteBuf fullByteBuf = channel.alloc().compositeBuffer(2);
fullByteBuf.addComponent(headerBuf);
fullByteBuf.writerIndex(headerBuf.readableBytes());
if (message != null) {
fullByteBuf.addComponent(message);
fullByteBuf.writerIndex(fullByteBuf.writerIndex() + message.readableBytes());
}
// Send
statTxMsg.mark();
statTxBytes.mark(fullByteBuf.readableBytes());
channel.writeAndFlush(fullByteBuf);
} catch (Exception e) {
statError.inc();
throw new IllegalStateException("Could not send message to " + destination, e);
}
}
private boolean isExpired(Channel channel) {
Long channelOpenTime = channelOpenTimes.get(channel);
return channelOpenTime != null
&& System.currentTimeMillis() - channelOpenTime >= config.getMaxChannelLifeMillis();
}
@Override
public void registerCallback(int messageType, HelixIPCCallback callback) {
callbacks.put(messageType, callback);
}
@ChannelHandler.Sharable
private class HelixIPCCallbackHandler extends SimpleChannelInboundHandler {
HelixIPCCallbackHandler() {
super(false); // we will manage reference
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf byteBuf) throws Exception {
try {
int idx = 0;
// Message length
int messageLength = byteBuf.readInt();
idx += 4;
// Message version
@SuppressWarnings("unused")
int messageVersion = byteBuf.readInt();
idx += 4;
// Message type
int messageType = byteBuf.readInt();
idx += 4;
// Message ID
UUID messageId = new UUID(byteBuf.readLong(), byteBuf.readLong());
idx += 16;
// Cluster
byteBuf.readerIndex(idx);
int clusterSize = byteBuf.readInt();
idx += 4;
checkLength("clusterSize", clusterSize, messageLength);
String clusterName = toNonEmptyString(clusterSize, byteBuf);
idx += clusterSize;
// Resource
byteBuf.readerIndex(idx);
int resourceSize = byteBuf.readInt();
idx += 4;
checkLength("resourceSize", resourceSize, messageLength);
String resourceName = toNonEmptyString(resourceSize, byteBuf);
idx += resourceSize;
// Partition
byteBuf.readerIndex(idx);
int partitionSize = byteBuf.readInt();
idx += 4;
checkLength("partitionSize", partitionSize, messageLength);
String partitionName = toNonEmptyString(partitionSize, byteBuf);
idx += partitionSize;
// State
byteBuf.readerIndex(idx);
int stateSize = byteBuf.readInt();
idx += 4;
checkLength("stateSize", stateSize, messageLength);
String state = toNonEmptyString(stateSize, byteBuf);
idx += stateSize;
// Source instance
byteBuf.readerIndex(idx);
int srcInstanceSize = byteBuf.readInt();
idx += 4;
checkLength("srcInstanceSize", srcInstanceSize, messageLength);
String srcInstance = toNonEmptyString(srcInstanceSize, byteBuf);
idx += srcInstanceSize;
// Destination instance
byteBuf.readerIndex(idx);
int dstInstanceSize = byteBuf.readInt();
idx += 4;
checkLength("dstInstanceSize", dstInstanceSize, messageLength);
String dstInstance = toNonEmptyString(dstInstanceSize, byteBuf);
idx += dstInstanceSize;
// Position at message
byteBuf.readerIndex(idx + 4);
// Error check
if (dstInstance == null) {
throw new IllegalStateException("Received message addressed to null destination from "
+ srcInstance);
} else if (!dstInstance.equals(config.getInstanceName())) {
throw new IllegalStateException(config.getInstanceName()
+ " received message addressed to " + dstInstance + " from " + srcInstance);
} else if (callbacks.get(messageType) == null) {
throw new IllegalStateException("No callback registered for message type " + messageType);
}
// Build scope
HelixMessageScope scope =
new HelixMessageScope.Builder().cluster(clusterName).resource(resourceName)
.partition(partitionName).state(state).sourceInstance(srcInstance).build();
// Get callback
HelixIPCCallback callback = callbacks.get(messageType);
if (callback == null) {
throw new IllegalStateException("No callback registered for message type " + messageType);
}
// Handle callback
callback.onMessage(scope, messageId, byteBuf);
// Stats
statRxMsg.mark();
statRxBytes.mark(messageLength);
} finally {
byteBuf.release();
}
}
@Override
public void exceptionCaught(ChannelHandlerContext channelHandlerContext, Throwable cause) {
LOG.error(cause);
}
}
/** Given a byte buf w/ a certain reader index, encodes the next length bytes as a String */
private static String toNonEmptyString(int length, ByteBuf byteBuf) {
if (byteBuf.readableBytes() >= length) {
return byteBuf.toString(byteBuf.readerIndex(), length, Charset.defaultCharset());
}
return null;
}
/** Writes [s.length(), s] to buf, or [0] if s is null */
private static void writeStringWithLength(ByteBuf buf, String s) {
if (s == null) {
buf.writeInt(0);
return;
}
buf.writeInt(s.length());
for (int i = 0; i < s.length(); i++) {
buf.writeByte(s.charAt(i));
}
}
/** Returns the length of a string, or 0 if s is null */
private static int getLength(String s) {
return s == null ? 0 : s.length();
}
/**
* @throws java.lang.IllegalArgumentException if length > messageLength (attempt to prevent OOM
* exceptions)
*/
private static void checkLength(String fieldName, int length, int messageLength)
throws IllegalArgumentException {
if (length > messageLength) {
throw new IllegalArgumentException(fieldName + "=" + length
+ " is greater than messageLength=" + messageLength);
}
}
public static class Config {
private String instanceName;
private int port;
private int numConnections = 1;
private long maxChannelLifeMillis = 5000;
public Config setInstanceName(String instanceName) {
this.instanceName = instanceName;
return this;
}
public Config setPort(int port) {
this.port = port;
return this;
}
public Config setNumConnections(int numConnections) {
this.numConnections = numConnections;
return this;
}
public Config setMaxChannelLifeMillis(long maxChannelLifeMillis) {
this.maxChannelLifeMillis = maxChannelLifeMillis;
return this;
}
public String getInstanceName() {
return instanceName;
}
public int getPort() {
return port;
}
public int getNumConnections() {
return numConnections;
}
public long getMaxChannelLifeMillis() {
return maxChannelLifeMillis;
}
}
}
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