/**
* 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.gateway.topology.file;
import org.apache.commons.digester3.Digester;
import org.apache.commons.digester3.binder.DigesterLoader;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;
import org.apache.commons.io.monitor.FileAlterationListener;
import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;
import org.apache.commons.io.monitor.FileAlterationMonitor;
import org.apache.commons.io.monitor.FileAlterationObserver;
import org.apache.hadoop.gateway.GatewayMessages;
import org.apache.hadoop.gateway.i18n.messages.MessagesFactory;
import org.apache.hadoop.gateway.topology.Topology;
import org.apache.hadoop.gateway.topology.TopologyEvent;
import org.apache.hadoop.gateway.topology.TopologyListener;
import org.apache.hadoop.gateway.topology.TopologyMonitor;
import org.apache.hadoop.gateway.topology.TopologyProvider;
import org.apache.hadoop.gateway.topology.builder.TopologyBuilder;
import org.apache.hadoop.gateway.topology.xml.AmbariFormatXmlTopologyRules;
import org.apache.hadoop.gateway.topology.xml.KnoxFormatXmlTopologyRules;
import org.xml.sax.SAXException;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import static org.apache.commons.digester3.binder.DigesterLoader.newLoader;
//import org.codehaus.plexus.util.FileUtils;
public class FileTopologyProvider
extends FileAlterationListenerAdaptor
implements TopologyProvider, TopologyMonitor, FileFilter, FileAlterationListener {
private static GatewayMessages log = MessagesFactory.get( GatewayMessages.class );
private static DigesterLoader digesterLoader = newLoader( new KnoxFormatXmlTopologyRules(), new AmbariFormatXmlTopologyRules() );
private static final List<String> SUPPORTED_TOPOLOGY_FILE_EXTENSIONS = new ArrayList<String>();
static {
SUPPORTED_TOPOLOGY_FILE_EXTENSIONS.add("xml");
SUPPORTED_TOPOLOGY_FILE_EXTENSIONS.add("conf");
}
private FileAlterationMonitor monitor;
private File directory;
private Set<TopologyListener> listeners;
private volatile Map<File,Topology> topologies;
FileTopologyProvider( FileAlterationMonitor monitor, File directory ) {
this.directory = directory;
this.monitor = monitor;
FileAlterationObserver observer = new FileAlterationObserver( this.directory, this );
observer.addListener( this );
monitor.addObserver( observer );
this.listeners = new HashSet<TopologyListener>();
this.topologies = new HashMap<File,Topology>(); //loadTopologies( this.directory );
}
public FileTopologyProvider( File directory ) throws IOException, SAXException {
this( new FileAlterationMonitor( 1000L ), directory );
}
private static Topology loadTopology( File file ) throws IOException, SAXException, URISyntaxException, InterruptedException {
final long TIMEOUT = 250; //ms
final long DELAY = 50; //ms
log.loadingTopologyFile( file.getAbsolutePath() );
Topology topology;
long start = System.currentTimeMillis();
while( true ) {
try {
topology = loadTopologyAttempt( file );
break;
} catch ( IOException e ) {
if( System.currentTimeMillis() - start < TIMEOUT ) {
log.failedToLoadTopologyRetrying( file.getAbsolutePath(), Long.toString( DELAY ), e );
Thread.sleep( DELAY );
} else {
throw e;
}
} catch ( SAXException e ) {
if( System.currentTimeMillis() - start < TIMEOUT ) {
log.failedToLoadTopologyRetrying( file.getAbsolutePath(), Long.toString( DELAY ), e );
Thread.sleep( DELAY );
} else {
throw e;
}
}
}
return topology;
}
private static Topology loadTopologyAttempt( File file ) throws IOException, SAXException, URISyntaxException {
Topology topology;Digester digester = digesterLoader.newDigester();
TopologyBuilder topologyBuilder = digester.parse( FileUtils.openInputStream( file ) );
topology = topologyBuilder.build();
topology.setUri( file.toURI() );
topology.setName( FilenameUtils.removeExtension( file.getName() ) );
topology.setTimestamp( file.lastModified() );
return topology;
}
private Map<File, Topology> loadTopologies( File directory ) {
Map<File, Topology> map = new HashMap<File, Topology>();
if( directory.exists() && directory.canRead() ) {
for( File file : directory.listFiles( this ) ) {
try {
map.put( file, loadTopology( file ) );
} catch( IOException e ) {
// Maybe it makes sense to throw exception
log.failedToLoadTopology( file.getAbsolutePath(), e );
} catch( SAXException e ) {
// Maybe it makes sense to throw exception
log.failedToLoadTopology( file.getAbsolutePath(), e );
} catch ( Exception e ) {
// Maybe it makes sense to throw exception
log.failedToLoadTopology( file.getAbsolutePath(), e );
}
}
}
return map;
}
public void reloadTopologies() {
try {
synchronized ( this ) {
Map<File,Topology> oldTopologies = topologies;
Map<File,Topology> newTopologies = loadTopologies( directory );
List<TopologyEvent> events = createChangeEvents( oldTopologies, newTopologies );
topologies = newTopologies;
notifyChangeListeners( events );
}
}
catch( Exception e ) {
// Maybe it makes sense to throw exception
log.failedToReloadTopologies( e );
}
}
private static List<TopologyEvent> createChangeEvents(
Map<File,Topology> oldTopologies,
Map<File,Topology> newTopologies ) {
ArrayList<TopologyEvent> events = new ArrayList<TopologyEvent>();
// Go through the old topologies and find anything that was deleted.
for( File file : oldTopologies.keySet() ) {
if( !newTopologies.containsKey( file ) ) {
events.add( new TopologyEvent( TopologyEvent.Type.DELETED, oldTopologies.get( file ) ) );
}
}
// Go through the new topologies and figure out what was updated vs added.
for( File file : newTopologies.keySet() ) {
if( oldTopologies.containsKey( file ) ) {
Topology oldTopology = oldTopologies.get( file );
Topology newTopology = newTopologies.get( file );
if( newTopology.getTimestamp() > oldTopology.getTimestamp() ) {
events.add( new TopologyEvent( TopologyEvent.Type.UPDATED, newTopologies.get( file ) ) );
}
} else {
events.add( new TopologyEvent( TopologyEvent.Type.CREATED, newTopologies.get( file ) ) );
}
}
return events ;
}
private void notifyChangeListeners( List<TopologyEvent> events ) {
for( TopologyListener listener : listeners ) {
try {
listener.handleTopologyEvent( events );
} catch( RuntimeException e ) {
log.failedToHandleTopologyEvents( e );
}
}
}
@Override
public Collection<Topology> getTopologies() {
Map<File,Topology> map = topologies;
return Collections.unmodifiableCollection( map.values() );
}
@Override
public void addTopologyChangeListener( TopologyListener listener ) {
listeners.add( listener );
}
@Override
public void startMonitor() throws Exception {
monitor.start();
}
@Override
public void stopMonitor() throws Exception {
monitor.stop();
}
@Override
public boolean accept( File file ) {
boolean accept = false;
if( !file.isDirectory() && file.canRead() ) {
String extension = FilenameUtils.getExtension( file.getName() );
if( SUPPORTED_TOPOLOGY_FILE_EXTENSIONS.contains( extension ) ) {
accept = true;
}
}
return accept;
}
@Override
public void onFileCreate( File file ) {
onFileChange( file );
}
@Override
public void onFileDelete(java.io.File file) {
onFileChange( file );
}
@Override
public void onFileChange( File file ) {
reloadTopologies();
}
}