/*
* Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
*
* Project and contact information: http://www.cascading.org/
*
* This file is part of the Cascading project.
*
* Licensed 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 cascading.management;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import cascading.cascade.CascadeException;
import cascading.management.state.ClientState;
import cascading.property.PropertyUtil;
import cascading.provider.CascadingService;
import cascading.provider.ServiceLoader;
import cascading.util.ShutdownUtil;
import cascading.util.Util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Class CascadingServices is the root class for pluggable services Cascading can call out to for distributed
* monitoring and management systems.
* <p/>
* Be default all services will be loaded from the jar {@code cascading/management/service.properties}
* ({@link #DEFAULT_PROPERTIES}) resource is found in. If the
* property {@link #CONTAINER_ENABLED} value is {@code false}, a ClassLoader container will not be created.
* <p/>
* For this to work, all service implementation and dependencies must be archived into a single jar.
* <p/>
* If any packages in the jar should be excluded, set a comma delimited list of names via the {@link #CONTAINER_EXCLUDE}
* property.
* <p/>
* If the file {@code cascading-service.properties} ({@link CascadingServices#CASCADING_SERVICES}) is found in the
* CLASSPATH, the {@code cascading.management.service.jar} property value will be used to search for
* {@code cascading/management/service.properties} resource.
*
* @see CascadingService
*/
public class CascadingServices
{
private static final Logger LOG = LoggerFactory.getLogger( CascadingServices.class );
public static final String CASCADING_SERVICES = "cascading-service.properties";
public static final String CASCADING_SERVICES_JAR = "cascading.management.service.jar";
public static final String DEFAULT_PROPERTIES = "cascading/management/service.properties";
public static final String CONTAINER_ENABLED = "cascading.management.container.enabled";
public static final String CONTAINER_EXCLUDE = "cascading.management.container.exclude";
static Properties defaultProperties;
static URL libraryURL;
static String[] exclusions;
Map<Object, Object> properties;
MetricsService metricsService;
DocumentService documentService;
boolean enableContainer;
static
{
ClassLoader classLoader = CascadingServices.class.getClassLoader();
// load all properties from cascading-services.properties
defaultProperties = loadProperties( new Properties(), CASCADING_SERVICES, classLoader );
libraryURL = getLibraryURL();
if( libraryURL != null )
classLoader = new URLClassLoader( new URL[]{libraryURL} );
// load additional, if only, properties from file in resource jar
defaultProperties = loadProperties( new Properties( defaultProperties ), DEFAULT_PROPERTIES, classLoader );
// if resources jar is on primary classpath, find the jar so we can isolate it when loading services
if( libraryURL == null )
libraryURL = parseLibraryURL( classLoader, DEFAULT_PROPERTIES );
exclusions = Util.removeNulls( defaultProperties.getProperty( CONTAINER_EXCLUDE, "" ).split( "," ) );
}
private static URL parseLibraryURL( ClassLoader classLoader, String resource )
{
URL url = classLoader.getResource( resource );
if( url != null )
{
try
{
String path = url.toURI().getSchemeSpecificPart();
int endIndex = path.lastIndexOf( '!' );
if( endIndex != -1 )
path = path.substring( 0, endIndex );
if( path.endsWith( ".jar" ) )
return new URL( path );
}
catch( Exception exception )
{
LOG.warn( "unable to parse resource library: {}", url, exception );
}
}
return null;
}
private static URL getLibraryURL()
{
String property = defaultProperties.getProperty( CASCADING_SERVICES_JAR );
if( property == null )
return null;
try
{
URI uri = URI.create( property );
if( !uri.isAbsolute() )
uri = new URI( "file", uri.getAuthority(), uri.getPath(), uri.getQuery(), uri.getFragment() );
return uri.toURL();
}
catch( Exception exception )
{
LOG.warn( "property: {}, has invalid URL value: {}", CASCADING_SERVICES_JAR, property );
}
return null;
}
private static Properties loadProperties( Properties properties, String resource, ClassLoader classLoader )
{
InputStream input = classLoader.getResourceAsStream( resource );
try
{
if( input != null )
{
URL url = parseLibraryURL( classLoader, resource );
if( url != null )
LOG.info( "loading properties: {}, from jar: {}", resource, url );
else
LOG.info( "loading properties: {}", resource );
properties.load( input );
}
}
catch( IOException exception )
{
LOG.warn( "unable to load properties from {}", resource, exception );
}
return properties;
}
private synchronized ServiceLoader getServiceUtil()
{
return ServiceLoader.getInstance( enableContainer ? libraryURL : null, exclusions );
}
public CascadingServices( Map<Object, Object> properties )
{
this.properties = PropertyUtil.createProperties( properties, defaultProperties );
this.enableContainer = PropertyUtil.getProperty( properties, CONTAINER_ENABLED, defaultProperties.getProperty( CONTAINER_ENABLED, "false" ) ).equalsIgnoreCase( "true" );
}
private Map<Object, Object> getProperties()
{
return properties;
}
public MetricsService getMetricsService()
{
if( metricsService == null )
metricsService = createMetricsService();
return metricsService;
}
public DocumentService getDocumentService()
{
if( documentService == null )
documentService = createDocumentService();
return documentService;
}
public ClientState createClientState( String id )
{
ClientState clientState = (ClientState) getServiceUtil().loadServiceFrom( defaultProperties, getProperties(), ClientState.STATE_SERVICE_CLASS_PROPERTY );
if( clientState != null )
{
clientState.initialize( this, id );
return clientState;
}
return ClientState.NULL;
}
protected MetricsService createMetricsService()
{
MetricsService service = (MetricsService) getServiceUtil().loadSingletonServiceFrom( defaultProperties, getProperties(), MetricsService.METRICS_SERVICE_CLASS_PROPERTY );
if( service != null )
{
registerShutdownHook( service );
return service;
}
return new NullMetricsService();
}
protected DocumentService createDocumentService()
{
DocumentService service = (DocumentService) getServiceUtil().loadSingletonServiceFrom( defaultProperties, getProperties(), DocumentService.DOCUMENT_SERVICE_CLASS_PROPERTY );
if( service != null )
{
registerShutdownHook( service );
return service;
}
return new NullDocumentService();
}
private void registerShutdownHook( final CascadingService service )
{
if( service == null )
return;
ShutdownUtil.addHook( new ShutdownUtil.Hook()
{
@Override
public Priority priority()
{
return Priority.SERVICE_PROVIDER;
}
@Override
public void execute()
{
try
{
service.stopService();
}
catch( Throwable throwable )
{
// safe to throw exception here so message is logged
LOG.error( "failed stopping cascading service", throwable );
throw new CascadeException( "failed stopping cascading service", throwable );
}
}
} );
}
/** Class NullDocumentService provides a null implementation. */
public static class NullDocumentService implements DocumentService
{
@Override
public boolean isEnabled()
{
return false;
}
@Override
public void setProperties( Map<Object, Object> properties )
{
}
@Override
public void startService()
{
}
@Override
public void stopService()
{
}
@Override
public void put( String key, Object object )
{
}
@Override
public void put( String type, String key, Object object )
{
}
@Override
public Map get( String type, String key )
{
return null;
}
@Override
public boolean supportsFind()
{
return false;
}
@Override
public List<Map<String, Object>> find( String type, String[] query )
{
return null;
}
}
/** Class NullMetricsService provides a null implementation. */
public static class NullMetricsService implements MetricsService
{
@Override
public boolean isEnabled()
{
return false;
}
@Override
public void increment( String[] context, int amount )
{
}
@Override
public void set( String[] context, String value )
{
}
@Override
public void set( String[] context, int value )
{
}
@Override
public void set( String[] context, long value )
{
}
@Override
public String getString( String[] context )
{
return null;
}
@Override
public int getInt( String[] context )
{
return 0;
}
@Override
public long getLong( String[] context )
{
return 0;
}
@Override
public boolean compareSet( String[] context, String isValue, String toValue )
{
return true;
}
@Override
public boolean compareSet( String[] context, int isValue, int toValue )
{
return true;
}
@Override
public boolean compareSet( String[] context, long isValue, long toValue )
{
return true;
}
@Override
public void setProperties( Map<Object, Object> properties )
{
}
@Override
public void startService()
{
}
@Override
public void stopService()
{
}
}
}