Add TcpChannel to unify Transport implementations

core/src/main/java/org/elasticsearch/action/ActionListener.java

@@ -24,6 +24,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
 /**
@@ -69,6 +70,50 @@ public void onFailure(Exception e) {
         };
     }
 
+    /**
+     * Creates a listener that listens for a response (or failure) and executes the
+     * corresponding runnable when the response (or failure) is received.
+     *
+     * @param runnable the runnable that will be called in event of success or failure
+     * @param <Response> the type of the response
+     * @return a listener that listens for responses and invokes the runnable when received
+     */
+    static <Response> ActionListener<Response> wrap(Runnable runnable) {
+        return new ActionListener<Response>() {
+            @Override
+            public void onResponse(Response response) {
+                runnable.run();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                runnable.run();
+            }
+        };
+    }
+
+    /**
+     * Converts a listener to a {@link BiConsumer} for compatibility with the {@link java.util.concurrent.CompletableFuture}
+     * api.
+     *
+     * @param listener that will be wrapped
+     * @param <Response> the type of the response
+     * @return a bi consumer that will complete the wrapped listener
+     */
+    static <Response> BiConsumer<Response, Throwable> toBiConsumer(ActionListener<Response> listener) {
+        return (tcpChannel, throwable) -> {
+            if (throwable == null) {
+                listener.onResponse(tcpChannel);
+            } else {
+                if (throwable instanceof Exception) {
+                    listener.onFailure((Exception) throwable);
+                } else {
+                    listener.onFailure(new Exception(throwable));
+                }
+            }
+        };
+    }
+
     /**
      * Notifies every given listener with the response passed to {@link #onResponse(Object)}. If a listener itself throws an exception
      * the exception is forwarded to {@link #onFailure(Exception)}. If in turn {@link #onFailure(Exception)} fails all remaining

core/src/main/java/org/elasticsearch/transport/ConnectionProfile.java

@@ -208,12 +208,12 @@ private ConnectionTypeHandle(int offset, int length, Set<TransportRequestOptions
          * Returns one of the channels out configured for this handle. The channel is selected in a round-robin
          * fashion.
          */
-        <T> T getChannel(T[] channels) {
+        <T> T getChannel(List<T> channels) {
             if (length == 0) {
                 throw new IllegalStateException("can't select channel size is 0 for types: " + types);
             }
-            assert channels.length >= offset + length : "illegal size: " + channels.length + " expected >= " + (offset + length);
-            return channels[offset + Math.floorMod(counter.incrementAndGet(), length)];
+            assert channels.size() >= offset + length : "illegal size: " + channels.size() + " expected >= " + (offset + length);
+            return channels.get(offset + Math.floorMod(counter.incrementAndGet(), length));
         }
 
         /**
@@ -223,5 +223,4 @@ Set<TransportRequestOptions.Type> getTypes() {
             return types;
         }
     }
-
 }

core/src/main/java/org/elasticsearch/transport/TcpChannel.java

@@ -0,0 +1,169 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.elasticsearch.transport;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.elasticsearch.action.ActionFuture;
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.support.PlainActionFuture;
+import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.common.lease.Releasable;
+import org.elasticsearch.common.lease.Releasables;
+import org.elasticsearch.common.unit.TimeValue;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+
+/**
+ * This is a tcp channel representing a single channel connection to another node. It is the base channel
+ * abstraction used by the {@link TcpTransport} and {@link TransportService}. All tcp transport
+ * implementations must return channels that adhere to the required method contracts.
+ */
+public interface TcpChannel extends Releasable {
+
+    /**
+     * Closes the channel. This might be an asynchronous process. There is notguarantee that the channel
+     * will be closed when this method returns. Use the {@link #addCloseListener(ActionListener)} method
+     * to implement logic that depends on knowing when the channel is closed.
+     */
+    void close();
+
+    /**
+     * Adds a listener that will be executed when the channel is closed. If the channel is still open when
+     * this listener is added, the listener will be executed by the thread that eventually closes the
+     * channel. If the channel is already closed when the listener is added the listener will immediately be
+     * executed by the thread that is attempting to add the listener.
+     *
+     * @param listener to be executed
+     */
+    void addCloseListener(ActionListener<TcpChannel> listener);
+
+
+    /**
+     * This sets the low level socket option {@link java.net.StandardSocketOptions} SO_LINGER on a channel.
+     *
+     * @param value to set for SO_LINGER
+     * @throws IOException that can be throw by the low level socket implementation
+     */
+    void setSoLinger(int value) throws IOException;
+
+
+    /**
+     * Indicates whether a channel is currently open
+     *
+     * @return boolean indicating if channel is open
+     */
+    boolean isOpen();
+
+    /**
+     * Closes the channel.
+     *
+     * @param channel to close
+     * @param blocking indicates if we should block on channel close
+     */
+    static <C extends TcpChannel> void closeChannel(C channel, boolean blocking) {
+        closeChannels(Collections.singletonList(channel), blocking);
+    }
+
+    /**
+     * Closes the channels.
+     *
+     * @param channels to close
+     * @param blocking indicates if we should block on channel close
+     */
+    static <C extends TcpChannel> void closeChannels(List<C> channels, boolean blocking) {
+        if (blocking) {
+            ArrayList<ActionFuture<TcpChannel>> futures = new ArrayList<>(channels.size());
+            for (final C channel : channels) {
+                if (channel.isOpen()) {
+                    PlainActionFuture<TcpChannel> closeFuture = PlainActionFuture.newFuture();
+                    channel.addCloseListener(closeFuture);
+                    channel.close();
+                    futures.add(closeFuture);
+                }
+            }
+            blockOnFutures(futures);
+        } else {
+            Releasables.close(channels);
+        }
+    }
+
+    /**
+     * Awaits for all of the pending connections to complete. Will throw an exception if at least one of the
+     * connections fails.
+     *
+     * @param discoveryNode the node for the pending connections
+     * @param connectionFutures representing the pending connections
+     * @param connectTimeout to wait for a connection
+     * @param <C> the type of channel
+     * @throws ConnectTransportException if one of the connections fails
+     */
+    static <C extends TcpChannel> void awaitConnected(DiscoveryNode discoveryNode, List<ActionFuture<C>> connectionFutures,
+                                                      TimeValue connectTimeout) throws ConnectTransportException {
+        Exception connectionException = null;
+        boolean allConnected = true;
+
+        for (ActionFuture<C> connectionFuture : connectionFutures) {
+            try {
+                connectionFuture.get(connectTimeout.getMillis(), TimeUnit.MILLISECONDS);
+            } catch (TimeoutException e) {
+                allConnected = false;
+                break;
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                throw new IllegalStateException(e);
+            } catch (ExecutionException e) {
+                allConnected = false;
+                connectionException = (Exception) e.getCause();
+                break;
+            }
+        }
+
+        if (allConnected == false) {
+            if (connectionException == null) {
+                throw new ConnectTransportException(discoveryNode, "connect_timeout[" + connectTimeout + "]");
+            } else {
+                throw new ConnectTransportException(discoveryNode, "connect_exception", connectionException);
+            }
+        }
+    }
+
+    static void blockOnFutures(List<ActionFuture<TcpChannel>> futures) {
+        for (ActionFuture<TcpChannel> future : futures) {
+            try {
+                future.get();
+            } catch (ExecutionException e) {
+                // Ignore as we are only interested in waiting for the close process to complete. Logging
+                // close exceptions happens elsewhere.
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                throw new IllegalStateException("Future got interrupted", e);
+            }
+        }
+    }
+}