/**
* 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.hadoop.hdfs.tools.offlineImageViewer;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.concurrent.Executors;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.channel.group.ChannelGroup;
import org.jboss.netty.channel.group.DefaultChannelGroup;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
import org.jboss.netty.handler.codec.http.HttpRequestDecoder;
import org.jboss.netty.handler.codec.http.HttpResponseEncoder;
import org.jboss.netty.handler.codec.string.StringEncoder;
import com.google.common.annotations.VisibleForTesting;
/**
* WebImageViewer loads a fsimage and exposes read-only WebHDFS API for its
* namespace.
*/
public class WebImageViewer {
public static final Log LOG = LogFactory.getLog(WebImageViewer.class);
private Channel channel;
private InetSocketAddress address;
private final ChannelFactory factory =
new NioServerSocketChannelFactory(Executors.newCachedThreadPool(),
Executors.newCachedThreadPool(), 1);
private final ServerBootstrap bootstrap = new ServerBootstrap(factory);
static final ChannelGroup allChannels =
new DefaultChannelGroup("WebImageViewer");
public WebImageViewer(InetSocketAddress address) {
this.address = address;
}
/**
* Start WebImageViewer and wait until the thread is interrupted.
* @param fsimage the fsimage to load.
* @throws IOException if failed to load the fsimage.
*/
public void initServerAndWait(String fsimage) throws IOException {
initServer(fsimage);
try {
channel.getCloseFuture().await();
} catch (InterruptedException e) {
LOG.info("Interrupted. Stopping the WebImageViewer.");
shutdown();
}
}
/**
* Start WebImageViewer.
* @param fsimage the fsimage to load.
* @throws IOException if fail to load the fsimage.
*/
@VisibleForTesting
public void initServer(String fsimage) throws IOException {
FSImageLoader loader = FSImageLoader.load(fsimage);
ChannelPipeline pipeline = Channels.pipeline();
pipeline.addLast("channelTracker", new SimpleChannelUpstreamHandler() {
@Override
public void channelOpen(ChannelHandlerContext ctx, ChannelStateEvent e)
throws Exception {
allChannels.add(e.getChannel());
}
});
pipeline.addLast("httpDecoder", new HttpRequestDecoder());
pipeline.addLast("requestHandler", new FSImageHandler(loader));
pipeline.addLast("stringEncoder", new StringEncoder());
pipeline.addLast("httpEncoder", new HttpResponseEncoder());
bootstrap.setPipeline(pipeline);
channel = bootstrap.bind(address);
allChannels.add(channel);
address = (InetSocketAddress) channel.getLocalAddress();
LOG.info("WebImageViewer started. Listening on " + address.toString()
+ ". Press Ctrl+C to stop the viewer.");
}
/**
* Stop WebImageViewer.
*/
@VisibleForTesting
public void shutdown() {
allChannels.close().awaitUninterruptibly();
factory.releaseExternalResources();
}
/**
* Get the listening port.
* @return the port WebImageViewer is listening on
*/
@VisibleForTesting
public int getPort() {
return address.getPort();
}
}