opendaylight/commons/protocol-framework/src/main/java/org/opendaylight/protocol/framework/ProtocolSessionPromise.java

   1 /*
   2  * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.protocol.framework;
   9
  10 import com.google.common.base.Preconditions;
  11 import io.netty.bootstrap.Bootstrap;
  12 import io.netty.channel.ChannelFuture;
  13 import io.netty.channel.ChannelFutureListener;
  14 import io.netty.channel.ChannelOption;
  15 import io.netty.util.concurrent.DefaultPromise;
  16 import io.netty.util.concurrent.EventExecutor;
  17 import io.netty.util.concurrent.Future;
  18 import io.netty.util.concurrent.FutureListener;
  19 import io.netty.util.concurrent.Promise;
  20 import java.net.InetSocketAddress;
  21 import javax.annotation.concurrent.GuardedBy;
  22 import javax.annotation.concurrent.ThreadSafe;
  23 import org.slf4j.Logger;
  24 import org.slf4j.LoggerFactory;
  25
  26 @ThreadSafe
  27 final class ProtocolSessionPromise<S extends ProtocolSession<?>> extends DefaultPromise<S> {
  28     private static final Logger LOG = LoggerFactory.getLogger(ProtocolSessionPromise.class);
  29     private final ReconnectStrategy strategy;
  30     private final InetSocketAddress address;
  31     private final Bootstrap b;
  32
  33     @GuardedBy("this")
  34     private Future<?> pending;
  35
  36     ProtocolSessionPromise(final EventExecutor executor, final InetSocketAddress address, final ReconnectStrategy strategy,
  37             final Bootstrap b) {
  38         super(executor);
  39         this.strategy = Preconditions.checkNotNull(strategy);
  40         this.address = Preconditions.checkNotNull(address);
  41         this.b = Preconditions.checkNotNull(b);
  42     }
  43
  44     synchronized void connect() {
  45         final Object lock = this;
  46
  47         try {
  48             final int timeout = this.strategy.getConnectTimeout();
  49
  50             LOG.debug("Promise {} attempting connect for {}ms", lock, timeout);
  51
  52             this.b.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, timeout);
  53             final ChannelFuture connectFuture = this.b.connect(this.address);
  54             // Add listener that attempts reconnect by invoking this method again.
  55             connectFuture.addListener(new BootstrapConnectListener(lock));
  56             this.pending = connectFuture;
  57         } catch (final Exception e) {
  58             LOG.info("Failed to connect to {}", address, e);
  59             setFailure(e);
  60         }
  61     }
  62
  63     @Override
  64     public synchronized boolean cancel(final boolean mayInterruptIfRunning) {
  65         if (super.cancel(mayInterruptIfRunning)) {
  66             this.pending.cancel(mayInterruptIfRunning);
  67             return true;
  68         }
  69
  70         return false;
  71     }
  72
  73     @Override
  74     public synchronized Promise<S> setSuccess(final S result) {
  75         LOG.debug("Promise {} completed", this);
  76         this.strategy.reconnectSuccessful();
  77         return super.setSuccess(result);
  78     }
  79
  80     private class BootstrapConnectListener implements ChannelFutureListener {
  81         private final Object lock;
  82
  83         public BootstrapConnectListener(final Object lock) {
  84             this.lock = lock;
  85         }
  86
  87         @Override
  88         public void operationComplete(final ChannelFuture cf) throws Exception {
  89             synchronized (lock) {
  90
  91                 LOG.debug("Promise {} connection resolved", lock);
  92
  93                 // Triggered when a connection attempt is resolved.
  94                 Preconditions.checkState(ProtocolSessionPromise.this.pending.equals(cf));
  95
  96                 /*
  97                  * The promise we gave out could have been cancelled,
  98                  * which cascades to the connect getting cancelled,
  99                  * but there is a slight race window, where the connect
 100                  * is already resolved, but the listener has not yet
 101                  * been notified -- cancellation at that point won't
 102                  * stop the notification arriving, so we have to close
 103                  * the race here.
 104                  */
 105                 if (isCancelled()) {
 106                     if (cf.isSuccess()) {
 107                         LOG.debug("Closing channel for cancelled promise {}", lock);
 108                         cf.channel().close();
 109                     }
 110                     return;
 111                 }
 112
 113                 if(cf.isSuccess()) {
 114                     LOG.debug("Promise {} connection successful", lock);
 115                     return;
 116                 }
 117
 118                 LOG.debug("Attempt to connect to {} failed", ProtocolSessionPromise.this.address, cf.cause());
 119
 120                 final Future<Void> rf = ProtocolSessionPromise.this.strategy.scheduleReconnect(cf.cause());
 121                 rf.addListener(new ReconnectingStrategyListener());
 122                 ProtocolSessionPromise.this.pending = rf;
 123             }
 124         }
 125
 126         private class ReconnectingStrategyListener implements FutureListener<Void> {
 127             @Override
 128             public void operationComplete(final Future<Void> sf) {
 129                 synchronized (lock) {
 130                     // Triggered when a connection attempt is to be made.
 131                     Preconditions.checkState(ProtocolSessionPromise.this.pending.equals(sf));
 132
 133                     /*
 134                      * The promise we gave out could have been cancelled,
 135                      * which cascades to the reconnect attempt getting
 136                      * cancelled, but there is a slight race window, where
 137                      * the reconnect attempt is already enqueued, but the
 138                      * listener has not yet been notified -- if cancellation
 139                      * happens at that point, we need to catch it here.
 140                      */
 141                     if (!isCancelled()) {
 142                         if (sf.isSuccess()) {
 143                             connect();
 144                         } else {
 145                             setFailure(sf.cause());
 146                         }
 147                     }
 148                 }
 149             }
 150         }
 151
 152     }
 153
 154 }