netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/NetconfSessionPromise.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.netconf.nettyutil;
   9
  10 import static com.google.common.base.Preconditions.checkState;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import io.netty.bootstrap.Bootstrap;
  14 import io.netty.channel.ChannelFuture;
  15 import io.netty.channel.ChannelFutureListener;
  16 import io.netty.util.concurrent.DefaultPromise;
  17 import io.netty.util.concurrent.EventExecutor;
  18 import io.netty.util.concurrent.Future;
  19 import io.netty.util.concurrent.FutureListener;
  20 import io.netty.util.concurrent.Promise;
  21 import java.net.InetSocketAddress;
  22 import org.checkerframework.checker.lock.qual.GuardedBy;
  23 import org.opendaylight.netconf.api.NetconfSession;
  24 import org.slf4j.Logger;
  25 import org.slf4j.LoggerFactory;
  26
  27 @Deprecated
  28 final class NetconfSessionPromise<S extends NetconfSession> extends DefaultPromise<S> {
  29     private static final Logger LOG = LoggerFactory.getLogger(NetconfSessionPromise.class);
  30     private final ReconnectStrategy strategy;
  31     private InetSocketAddress address;
  32     private final Bootstrap bootstrap;
  33
  34     @GuardedBy("this")
  35     private Future<?> pending;
  36
  37     NetconfSessionPromise(final EventExecutor executor, final InetSocketAddress address,
  38             final ReconnectStrategy strategy, final Bootstrap bootstrap) {
  39         super(executor);
  40         this.strategy = requireNonNull(strategy);
  41         this.address = requireNonNull(address);
  42         this.bootstrap = requireNonNull(bootstrap);
  43     }
  44
  45     @SuppressWarnings("checkstyle:illegalCatch")
  46     synchronized void connect() {
  47         try {
  48             final int timeout = strategy.getConnectTimeout();
  49
  50             LOG.debug("Promise {} attempting connect for {}ms", this, timeout);
  51
  52             if (address.isUnresolved()) {
  53                 address = new InetSocketAddress(address.getHostName(), address.getPort());
  54             }
  55             final ChannelFuture connectFuture = bootstrap.connect(address);
  56             // Add listener that attempts reconnect by invoking this method again.
  57             connectFuture.addListener((ChannelFutureListener) this::channelConnectComplete);
  58             pending = connectFuture;
  59         } catch (final Exception e) {
  60             LOG.info("Failed to connect to {}", address, e);
  61             setFailure(e);
  62         }
  63     }
  64
  65     @Override
  66     public synchronized boolean cancel(final boolean mayInterruptIfRunning) {
  67         if (super.cancel(mayInterruptIfRunning)) {
  68             pending.cancel(mayInterruptIfRunning);
  69             return true;
  70         }
  71
  72         return false;
  73     }
  74
  75     @Override
  76     public synchronized Promise<S> setSuccess(final S result) {
  77         LOG.debug("Promise {} completed", this);
  78         strategy.reconnectSuccessful();
  79         return super.setSuccess(result);
  80     }
  81
  82     // Triggered when a connection attempt is resolved.
  83     private synchronized void channelConnectComplete(final ChannelFuture cf) {
  84         LOG.debug("Promise {} connection resolved", this);
  85         checkState(pending.equals(cf));
  86
  87         /*
  88          * The promise we gave out could have been cancelled,
  89          * which cascades to the connect getting cancelled,
  90          * but there is a slight race window, where the connect
  91          * is already resolved, but the listener has not yet
  92          * been notified -- cancellation at that point won't
  93          * stop the notification arriving, so we have to close
  94          * the race here.
  95          */
  96         if (isCancelled()) {
  97             if (cf.isSuccess()) {
  98                 LOG.debug("Closing channel for cancelled promise {}", this);
  99                 cf.channel().close();
 100             }
 101             return;
 102         }
 103
 104         if (cf.isSuccess()) {
 105             LOG.debug("Promise {} connection successful", this);
 106             return;
 107         }
 108
 109         LOG.debug("Attempt to connect to {} failed", address, cf.cause());
 110
 111         final Future<Void> rf = strategy.scheduleReconnect(cf.cause());
 112         rf.addListener(new ReconnectingStrategyListener());
 113         pending = rf;
 114     }
 115
 116     private class ReconnectingStrategyListener implements FutureListener<Void> {
 117         @Override
 118         public void operationComplete(final Future<Void> sf) {
 119             synchronized (NetconfSessionPromise.this) {
 120                 // Triggered when a connection attempt is to be made.
 121                 checkState(pending.equals(sf));
 122
 123                 /*
 124                  * The promise we gave out could have been cancelled,
 125                  * which cascades to the reconnect attempt getting
 126                  * cancelled, but there is a slight race window, where
 127                  * the reconnect attempt is already enqueued, but the
 128                  * listener has not yet been notified -- if cancellation
 129                  * happens at that point, we need to catch it here.
 130                  */
 131                 if (!isCancelled()) {
 132                     if (sf.isSuccess()) {
 133                         connect();
 134                     } else {
 135                         setFailure(sf.cause());
 136                     }
 137                 }
 138             }
 139         }
 140     }
 141 }