[GitHub] [incubator-uniffle] jerqi commented on a diff in pull request #771: [#584] feat(netty): Add transport client pool for netty

["jerqi (via GitHub)" <gi...@apache.org>]

jerqi commented on code in PR #771:
URL: https://github.com/apache/incubator-uniffle/pull/771#discussion_r1149979651


##########
common/src/main/java/org/apache/uniffle/common/netty/client/TransportClientFactory.java:
##########
@@ -0,0 +1,253 @@
+/*
+ * 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.uniffle.common.netty.client;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
+import java.util.Random;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicReference;
+
+import com.google.common.base.Preconditions;
+import io.netty.bootstrap.Bootstrap;
+import io.netty.buffer.PooledByteBufAllocator;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.socket.SocketChannel;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.uniffle.common.netty.IOMode;
+import org.apache.uniffle.common.netty.handle.TransportResponseHandler;
+import org.apache.uniffle.common.netty.protocol.MessageDecoder;
+import org.apache.uniffle.common.util.JavaUtils;
+import org.apache.uniffle.common.util.NettyUtils;
+
+public class TransportClientFactory implements Closeable {
+
+  /**
+   * A simple data structure to track the pool of clients between two peer nodes.
+   */
+  private static class ClientPool {
+    TransportClient[] clients;
+    Object[] locks;
+
+    ClientPool(int size) {
+      clients = new TransportClient[size];
+      locks = new Object[size];
+      for (int i = 0; i < size; i++) {
+        locks[i] = new Object();
+      }
+    }
+  }
+
+  private static final Logger logger = LoggerFactory.getLogger(TransportClientFactory.class);
+
+  private final TransportContext context;
+  private final TransportConf conf;
+  private final ConcurrentHashMap<SocketAddress, ClientPool> connectionPool;
+
+  /**
+   * Random number generator for picking connections between peers.
+   */
+  private final Random rand;
+
+  private final int numConnectionsPerPeer;
+
+  private final Class<? extends Channel> socketChannelClass;
+  private EventLoopGroup workerGroup;
+  private PooledByteBufAllocator pooledAllocator;
+
+  public TransportClientFactory(TransportContext context) {
+    this.context = Preconditions.checkNotNull(context);
+    this.conf = context.getConf();
+    this.connectionPool = new ConcurrentHashMap<>();
+    this.numConnectionsPerPeer = conf.numConnectionsPerPeer();
+    this.rand = new Random();
+
+    IOMode ioMode = conf.ioMode();
+    this.socketChannelClass = NettyUtils.getClientChannelClass(ioMode);
+    this.workerGroup =
+        NettyUtils.createEventLoop(ioMode, conf.clientThreads(), "netty-rpc-client");
+    this.pooledAllocator =
+        NettyUtils.createPooledByteBufAllocator(
+            conf.preferDirectBufs(), false, conf.clientThreads());
+  }
+
+  public TransportClient createClient(String remoteHost, int remotePort, int partitionId)
+      throws IOException, InterruptedException {
+    return createClient(remoteHost, remotePort, partitionId, new MessageDecoder());
+  }
+
+  public TransportClient createClient(
+      String remoteHost, int remotePort, int partitionId, ChannelInboundHandlerAdapter decoder)
+      throws IOException, InterruptedException {
+    // Get connection from the connection pool first.
+    // If it is not found or not active, create a new one.
+    // Use unresolved address here to avoid DNS resolution each time we creates a client.
+    final InetSocketAddress unresolvedAddress =
+        InetSocketAddress.createUnresolved(remoteHost, remotePort);
+
+    // Create the ClientPool if we don't have it yet.
+    ClientPool clientPool = connectionPool.get(unresolvedAddress);
+    if (clientPool == null) {
+      connectionPool.putIfAbsent(unresolvedAddress, new ClientPool(numConnectionsPerPeer));
+      clientPool = connectionPool.get(unresolvedAddress);
+    }
+
+    int clientIndex =
+        partitionId < 0 ? rand.nextInt(numConnectionsPerPeer) : partitionId % numConnectionsPerPeer;
+    TransportClient cachedClient = clientPool.clients[clientIndex];
+
+    if (cachedClient != null && cachedClient.isActive()) {
+      // Make sure that the channel will not timeout by updating the last use time of the
+      // handler. Then check that the client is still alive, in case it timed out before
+      // this code was able to update things.
+      TransportResponseHandler handler =
+          cachedClient.getChannel().pipeline().get(TransportResponseHandler.class);
+
+      if (cachedClient.isActive()) {
+        logger.trace(
+            "Returning cached connection to {}: {}", cachedClient.getSocketAddress(), cachedClient);
+        return cachedClient;
+      }
+    }
+
+    // If we reach here, we don't have an existing connection open. Let's create a new one.
+    // Multiple threads might race here to create new connections. Keep only one of them active.
+    final long preResolveHost = System.nanoTime();
+    final InetSocketAddress resolvedAddress = new InetSocketAddress(remoteHost, remotePort);
+    final long hostResolveTimeMs = (System.nanoTime() - preResolveHost) / 1000000;
+    if (hostResolveTimeMs > 2000) {
+      logger.warn("DNS resolution for {} took {} ms", resolvedAddress, hostResolveTimeMs);
+    } else {
+      logger.trace("DNS resolution for {} took {} ms", resolvedAddress, hostResolveTimeMs);
+    }
+
+    synchronized (clientPool.locks[clientIndex]) {
+      cachedClient = clientPool.clients[clientIndex];
+
+      if (cachedClient != null) {
+        if (cachedClient.isActive()) {
+          logger.trace("Returning cached connection to {}: {}", resolvedAddress, cachedClient);
+          return cachedClient;
+        } else {
+          logger.info("Found inactive connection to {}, creating a new one.", resolvedAddress);
+        }
+      }
+      clientPool.clients[clientIndex] = internalCreateClient(resolvedAddress, decoder);
+      return clientPool.clients[clientIndex];
+    }
+  }
+
+  public TransportClient createClient(String remoteHost, int remotePort)
+      throws IOException, InterruptedException {
+    return createClient(remoteHost, remotePort, -1);
+  }
+
+  /**
+   * Create a completely new {@link TransportClient} to the given remote host / port. This
+   * connection is not pooled.
+   *
+   * <p>As with {@link #createClient(String, int)}, this method is blocking.
+   */
+  private TransportClient internalCreateClient(
+      InetSocketAddress address, ChannelInboundHandlerAdapter decoder)
+      throws IOException, InterruptedException {
+    Bootstrap bootstrap = new Bootstrap();
+    bootstrap
+        .group(workerGroup)
+        .channel(socketChannelClass)
+        // Disable Nagle's Algorithm since we don't want packets to wait
+        .option(ChannelOption.TCP_NODELAY, true)
+        .option(ChannelOption.SO_KEEPALIVE, true)
+        .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, conf.connectTimeoutMs())
+        .option(ChannelOption.ALLOCATOR, pooledAllocator);
+
+    if (conf.receiveBuf() > 0) {
+      bootstrap.option(ChannelOption.SO_RCVBUF, conf.receiveBuf());
+    }
+
+    if (conf.sendBuf() > 0) {
+      bootstrap.option(ChannelOption.SO_SNDBUF, conf.sendBuf());
+    }
+
+    final AtomicReference<TransportClient> clientRef = new AtomicReference<>();
+    final AtomicReference<Channel> channelRef = new AtomicReference<>();
+
+    bootstrap.handler(
+        new ChannelInitializer<SocketChannel>() {
+          @Override
+          public void initChannel(SocketChannel ch) {
+            TransportResponseHandler transportResponseHandler = context.initializePipeline(ch, decoder);
+            TransportClient client = new TransportClient(ch, transportResponseHandler);
+            clientRef.set(client);
+            channelRef.set(ch);
+          }
+        });
+
+    // Connect to the remote server
+    ChannelFuture cf = bootstrap.connect(address);
+    if (!cf.await(conf.connectTimeoutMs())) {
+      throw new IOException(
+          String.format("Connecting to %s timed out (%s ms)", address, conf.connectTimeoutMs()));
+    } else if (cf.cause() != null) {
+      throw new IOException(String.format("Failed to connect to %s", address), cf.cause());
+    }
+
+    TransportClient client = clientRef.get();
+    assert client != null : "Channel future completed successfully with null client";
+
+    logger.debug("Connection to {} successful", address);
+
+    return client;
+  }
+
+  /**
+   * Close all connections in the connection pool, and shutdown the worker thread pool.
+   */
+  @Override
+  public void close() {
+    // Go through all clients and close them if they are active.
+    for (ClientPool clientPool : connectionPool.values()) {
+      for (int i = 0; i < clientPool.clients.length; i++) {
+        TransportClient client = clientPool.clients[i];
+        if (client != null) {
+          clientPool.clients[i] = null;
+          JavaUtils.closeQuietly(client);
+        }
+      }
+    }
+    connectionPool.clear();
+
+    // SPARK-19147

Review Comment:
   Could we remove this comment?



##########
common/src/main/java/org/apache/uniffle/common/netty/client/TransportClient.java:
##########
@@ -0,0 +1,144 @@
+/*
+ * 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.uniffle.common.netty.client;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.SocketAddress;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+
+import com.google.common.base.Preconditions;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.util.concurrent.Future;
+import io.netty.util.concurrent.GenericFutureListener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.uniffle.common.netty.handle.TransportResponseHandler;
+import org.apache.uniffle.common.netty.protocol.Message;
+import org.apache.uniffle.common.util.NettyUtils;
+
+
+public class TransportClient implements Closeable {
+  private static final Logger logger = LoggerFactory.getLogger(TransportClient.class);
+
+  private Channel channel;
+  private TransportResponseHandler handler;
+  private volatile boolean timedOut;
+
+  private static final AtomicLong counter = new AtomicLong();
+
+  public TransportClient(Channel channel, TransportResponseHandler handler) {
+    this.channel = Preconditions.checkNotNull(channel);
+    this.handler = Preconditions.checkNotNull(handler);
+    this.timedOut = false;
+  }
+
+  public Channel getChannel() {
+    return channel;
+  }
+
+  public boolean isActive() {
+    return !timedOut && (channel.isOpen() || channel.isActive());
+  }
+
+  public SocketAddress getSocketAddress() {
+    return channel.remoteAddress();
+  }
+
+  public ChannelFuture sendShuffleData(Message message, RpcResponseCallback callback) {
+    if (logger.isTraceEnabled()) {
+      logger.trace("Pushing data to {}", NettyUtils.getRemoteAddress(channel));
+    }
+    long requestId = requestId();
+    handler.addResponseCallback(requestId, callback);
+    RpcChannelListener listener = new RpcChannelListener(requestId, callback);
+    return channel.writeAndFlush(message).addListener(listener);
+  }
+
+  public static long requestId() {
+    return counter.getAndIncrement();
+  }
+
+  public class StdChannelListener implements GenericFutureListener<Future<? super Void>> {
+    final long startTime;
+    final Object requestId;
+
+    public StdChannelListener(Object requestId) {
+      this.startTime = System.currentTimeMillis();
+      this.requestId = requestId;
+    }
+
+    @Override
+    public void operationComplete(Future<? super Void> future) throws Exception {
+      if (future.isSuccess()) {
+        if (logger.isTraceEnabled()) {
+          long timeTaken = System.currentTimeMillis() - startTime;
+          logger.trace(
+              "Sending request {} to {} took {} ms",
+              requestId,
+              NettyUtils.getRemoteAddress(channel),
+              timeTaken);
+        }
+      } else {
+        String errorMsg =
+            String.format(
+                "Failed to send request %s to %s: %s, channel will be closed",
+                requestId, NettyUtils.getRemoteAddress(channel), future.cause());
+        logger.warn(errorMsg);
+        channel.close();
+        try {
+          handleFailure(errorMsg, future.cause());
+        } catch (Exception e) {
+          logger.error("Uncaught exception in RPC response callback handler!", e);
+        }
+      }
+    }
+
+    protected void handleFailure(String errorMsg, Throwable cause) {
+      logger.error("Error encountered " + errorMsg, cause);
+    }
+  }
+
+  private class RpcChannelListener extends StdChannelListener {
+    final long rpcRequestId;
+    final RpcResponseCallback callback;
+
+    RpcChannelListener(long rpcRequestId, RpcResponseCallback callback) {
+      super("RPC " + rpcRequestId);
+      this.rpcRequestId = rpcRequestId;
+      this.callback = callback;
+    }
+
+    @Override
+    protected void handleFailure(String errorMsg, Throwable cause) {
+      handler.removeRpcRequest(rpcRequestId);
+      callback.onFailure(new IOException(errorMsg, cause));
+    }
+  }
+
+
+  @Override
+  public void close() throws IOException {
+    // close is a local operation and should finish with milliseconds; timeout just to be safe
+    channel.close().awaitUninterruptibly(10, TimeUnit.SECONDS);

Review Comment:
   Why do we choose `10`?



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