/**
* 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.FilenameUtils;
import org.apache.commons.vfs2.FileChangeEvent;
import org.apache.commons.vfs2.FileContent;
import org.apache.commons.vfs2.FileListener;
import org.apache.commons.vfs2.FileName;
import org.apache.commons.vfs2.FileObject;
import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.VFS;
import org.apache.commons.vfs2.impl.DefaultFileMonitor;
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.IOException;
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 implements TopologyProvider, TopologyMonitor, FileListener {
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 DefaultFileMonitor monitor;
private FileObject directory;
private Set<TopologyListener> listeners;
private volatile Map<FileName, Topology> topologies;
// For unit testing.
FileTopologyProvider( DefaultFileMonitor monitor, FileObject directory ) throws IOException, SAXException {
this.directory = directory;
this.monitor = ( monitor != null ) ? monitor : new DefaultFileMonitor( this );
this.monitor.setRecursive( false );
this.monitor.addFile( this.directory );
this.listeners = new HashSet<TopologyListener>();
this.topologies = new HashMap<FileName, Topology>(); //loadTopologies( this.directory );
}
public FileTopologyProvider( File directory ) throws IOException, SAXException {
this( null, VFS.getManager().toFileObject( directory ) );
}
private static Topology loadTopology( FileObject file ) throws IOException, SAXException {
log.loadingTopologyFile( file.getName().getFriendlyURI() );
Digester digester = digesterLoader.newDigester();
FileContent content = file.getContent();
TopologyBuilder topologyBuilder = digester.parse( content.getInputStream() );
Topology topology = topologyBuilder.build();
topology.setName( FilenameUtils.removeExtension( file.getName().getBaseName() ) );
topology.setTimestamp( content.getLastModifiedTime() );
return topology;
}
private Map<FileName, Topology> loadTopologies( FileObject directory ) throws FileSystemException {
Map<FileName, Topology> map = new HashMap<FileName, Topology>();
if( directory.exists() && directory.getType().hasChildren() ) {
for( FileObject file : directory.getChildren() ) {
if( file.exists() && !file.getType().hasChildren() && SUPPORTED_TOPOLOGY_FILE_EXTENSIONS.contains( file.getName().getExtension() )) {
try {
map.put( file.getName(), loadTopology( file ) );
} catch( IOException e ) {
// Maybe it makes sense to throw exception
log.failedToLoadTopology( file.getName().getFriendlyURI(), e );
} catch( SAXException e ) {
// Maybe it makes sense to throw exception
log.failedToLoadTopology( file.getName().getFriendlyURI(), e );
} catch ( Exception e ) {
// Maybe it makes sense to throw exception
log.failedToLoadTopology( file.getName().getFriendlyURI(), e );
}
}
}
}
return map;
}
public void reloadTopologies() {
try {
synchronized ( this ) {
Map<FileName, Topology> oldTopologies = topologies;
Map<FileName, Topology> newTopologies = loadTopologies( directory );
List<TopologyEvent> events = createChangeEvents( oldTopologies, newTopologies );
topologies = newTopologies;
notifyChangeListeners( events );
}
} catch( FileSystemException e ) {
// Maybe it makes sense to throw exception
log.failedToReloadTopologies( e );
}
}
private static List<TopologyEvent> createChangeEvents(
Map<FileName, Topology> oldTopologies,
Map<FileName, Topology> newTopologies ) {
ArrayList<TopologyEvent> events = new ArrayList<TopologyEvent>();
// Go through the old topologies and find anything that was deleted.
for( FileName fileName : oldTopologies.keySet() ) {
if( !newTopologies.containsKey( fileName ) ) {
events.add( new TopologyEvent( TopologyEvent.Type.DELETED, oldTopologies.get( fileName ) ) );
}
}
// Go through the new topologies and figure out what was updated vs added.
for( FileName fileName : newTopologies.keySet() ) {
if( oldTopologies.containsKey( fileName ) ) {
Topology oldTopology = oldTopologies.get( fileName );
Topology newTopology = newTopologies.get( fileName );
if( newTopology.getTimestamp() > oldTopology.getTimestamp() ) {
events.add( new TopologyEvent( TopologyEvent.Type.UPDATED, newTopologies.get( fileName ) ) );
}
} else {
events.add( new TopologyEvent( TopologyEvent.Type.CREATED, newTopologies.get( fileName ) ) );
}
}
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<FileName, Topology> map = topologies;
return Collections.unmodifiableCollection( map.values() );
}
@Override
public void addTopologyChangeListener( TopologyListener listener ) {
listeners.add( listener );
}
@Override
public void startMonitor() {
monitor.start();
}
@Override
public void stopMonitor() {
monitor.stop();
}
private void handleFileEvent( FileChangeEvent fileChangeEvent ) throws FileSystemException {
FileObject file = fileChangeEvent.getFile();
if( file != null && ( !file.getType().hasChildren() || file.equals( directory ) ) ) {
reloadTopologies();
}
}
@Override
public void fileCreated( FileChangeEvent fileChangeEvent ) throws FileSystemException {
handleFileEvent( fileChangeEvent );
}
@Override
public void fileDeleted( FileChangeEvent fileChangeEvent ) throws FileSystemException {
handleFileEvent( fileChangeEvent );
}
@Override
public void fileChanged( FileChangeEvent fileChangeEvent ) throws FileSystemException {
handleFileEvent( fileChangeEvent );
}
}