trunk/activemq-optional/src/main/java/org/apache/activemq/transport/discovery/http/HTTPDiscoveryAgent.java - activemq - Git at Google

 /**
  * 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.activemq.transport.discovery.http;

 import java.io.IOException;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Scanner;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;

 import org.apache.activemq.Service;
 import org.apache.activemq.command.DiscoveryEvent;
 import org.apache.activemq.transport.discovery.DiscoveryAgent;
 import org.apache.activemq.transport.discovery.DiscoveryListener;
 import org.apache.activemq.util.IntrospectionSupport;
 import org.apache.commons.httpclient.HttpClient;
 import org.apache.commons.httpclient.methods.DeleteMethod;
 import org.apache.commons.httpclient.methods.GetMethod;
 import org.apache.commons.httpclient.methods.PutMethod;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 public class HTTPDiscoveryAgent implements DiscoveryAgent {

     private static final Logger LOG = LoggerFactory.getLogger(HTTPDiscoveryAgent.class);

     private String registryURL = "http://localhost:8080/discovery-registry/default";
     private HttpClient httpClient = new HttpClient();
     private AtomicBoolean running=new AtomicBoolean();
     private final AtomicReference<DiscoveryListener> discoveryListener = new AtomicReference<DiscoveryListener>();
     private final HashSet<String> registeredServices = new HashSet<String>();
     private final HashMap<String, SimpleDiscoveryEvent> discoveredServices = new HashMap<String, SimpleDiscoveryEvent>();
     private Thread thread;
     private long updateInterval = 1000*10;
     private String brokerName;
     private boolean startEmbeddRegistry=false;
     private Service jetty;
     private AtomicInteger startCounter=new AtomicInteger(0);


     private long initialReconnectDelay = 1000;
     private long maxReconnectDelay = 1000 * 30;
     private long backOffMultiplier = 2;
     private boolean useExponentialBackOff=true;
     private int maxReconnectAttempts;
     private final Object sleepMutex = new Object();
     private long minConnectTime = 5000;

     class SimpleDiscoveryEvent extends DiscoveryEvent {

         private int connectFailures;
         private long reconnectDelay = initialReconnectDelay;
         private long connectTime = System.currentTimeMillis();
         private AtomicBoolean failed = new AtomicBoolean(false);
         private AtomicBoolean removed = new AtomicBoolean(false);

         public SimpleDiscoveryEvent(String service) {
             super(service);
         }

     }


     public String getGroup() {
         return null;
     }

     public void registerService(String service) throws IOException {
         synchronized(registeredServices) {
             registeredServices.add(service);
         }
         doRegister(service);
     }

     synchronized private void doRegister(String service) {
         String url = registryURL;
         try {
             PutMethod method = new PutMethod(url);
 //            method.setParams(createParams());
             method.setRequestHeader("service", service);
             int responseCode = httpClient.executeMethod(method);
             LOG.debug("PUT to "+url+" got a "+responseCode);
         } catch (Exception e) {
             LOG.debug("PUT to "+url+" failed with: "+e);
         }
     }

     synchronized private void doUnRegister(String service) {
         String url = registryURL;
         try {
             DeleteMethod method = new DeleteMethod(url);
 //            method.setParams(createParams());
             method.setRequestHeader("service", service);
             int responseCode = httpClient.executeMethod(method);
             LOG.debug("DELETE to "+url+" got a "+responseCode);
         } catch (Exception e) {
             LOG.debug("DELETE to "+url+" failed with: "+e);
         }
     }

 //    private HttpMethodParams createParams() {
 //        HttpMethodParams params = new HttpMethodParams();
 //        params.setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(0,false));
 //        return params;
 //    }

     synchronized private Set<String> doLookup(long freshness) {
         String url = registryURL+"?freshness="+freshness;
         try {
             GetMethod method = new GetMethod(url);
 //            method.setParams(createParams());
             int responseCode = httpClient.executeMethod(method);
             LOG.debug("GET to "+url+" got a "+responseCode);
             if( responseCode == 200 ) {
                 Set<String> rc = new HashSet<String>();
                 Scanner scanner = new Scanner(method.getResponseBodyAsStream());
                 while( scanner.hasNextLine() ) {
                     String service = scanner.nextLine();
                     if( service.trim().length() != 0 ) {
                         rc.add(service);
                     }
                 }
                 return rc;
             } else {
                 LOG.debug("GET to "+url+" failed with response code: "+responseCode);
                 return null;
             }
         } catch (Exception e) {
             LOG.debug("GET to "+url+" failed with: "+e);
             return null;
         }
     }

     public void serviceFailed(DiscoveryEvent devent) throws IOException {

         final SimpleDiscoveryEvent event = (SimpleDiscoveryEvent)devent;
         if (event.failed.compareAndSet(false, true)) {
         	discoveryListener.get().onServiceRemove(event);
         	if(!event.removed.get()) {
 	        	// Setup a thread to re-raise the event...
 	            Thread thread = new Thread() {
 	                public void run() {

 	                    // We detect a failed connection attempt because the service
 	                    // fails right away.
 	                    if (event.connectTime + minConnectTime > System.currentTimeMillis()) {
 	                        LOG.debug("Failure occured soon after the discovery event was generated.  It will be clasified as a connection failure: "+event);

 	                        event.connectFailures++;

 	                        if (maxReconnectAttempts > 0 && event.connectFailures >= maxReconnectAttempts) {
 	                            LOG.debug("Reconnect attempts exceeded "+maxReconnectAttempts+" tries.  Reconnecting has been disabled.");
 	                            return;
 	                        }

 	                        synchronized (sleepMutex) {
 	                            try {
 	                                if (!running.get() || event.removed.get()) {
 	                                    return;
 	                                }
 	                                LOG.debug("Waiting "+event.reconnectDelay+" ms before attepting to reconnect.");
 	                                sleepMutex.wait(event.reconnectDelay);
 	                            } catch (InterruptedException ie) {
 	                                Thread.currentThread().interrupt();
 	                                return;
 	                            }
 	                        }

 	                        if (!useExponentialBackOff) {
 	                            event.reconnectDelay = initialReconnectDelay;
 	                        } else {
 	                            // Exponential increment of reconnect delay.
 	                            event.reconnectDelay *= backOffMultiplier;
 	                            if (event.reconnectDelay > maxReconnectDelay) {
 	                                event.reconnectDelay = maxReconnectDelay;
 	                            }
 	                        }

 	                    } else {
 	                        event.connectFailures = 0;
 	                        event.reconnectDelay = initialReconnectDelay;
 	                    }

 	                    if (!running.get() || event.removed.get()) {
 	                        return;
 	                    }

 	                    event.connectTime = System.currentTimeMillis();
 	                    event.failed.set(false);
 	                    discoveryListener.get().onServiceAdd(event);
 	                }
 	            };
 	            thread.setDaemon(true);
 	            thread.start();
         	}
         }
     }


     public void setBrokerName(String brokerName) {
         this.brokerName = brokerName;
     }

     public void setDiscoveryListener(DiscoveryListener discoveryListener) {
         this.discoveryListener.set(discoveryListener);
     }

     public void setGroup(String group) {
     }

     public void start() throws Exception {
         if( startCounter.addAndGet(1)==1 ) {
             if( startEmbeddRegistry ) {
                 jetty = createEmbeddedJettyServer();
                 Map props = new HashMap();
                 props.put("agent", this);
                 IntrospectionSupport.setProperties(jetty, props);
                 jetty.start();
             }

             running.set(true);
             thread = new Thread("HTTPDiscovery Agent") {
                 @Override
                 public void run() {
                     while(running.get()) {
                         try {
                             update();
                             Thread.sleep(updateInterval);
                         } catch (InterruptedException e) {
                             return;
                         }
                     }
                 }
             };
             thread.setDaemon(true);
             thread.start();
         }
     }

     /**
      * Create the EmbeddedJettyServer instance via reflection so that we can avoid a hard runtime dependency on
      * jetty.
      *
      * @return
      * @throws Exception
      */
     private Service createEmbeddedJettyServer()  throws Exception {
         Class clazz = HTTPDiscoveryAgent.class.getClassLoader().loadClass("org.apache.activemq.transport.discovery.http.EmbeddedJettyServer");
         return (Service)clazz.newInstance();
     }

     private void update() {
         // Register all our services...
         synchronized(registeredServices) {
             for (String service : registeredServices) {
                 doRegister(service);
             }
         }

         // Find new registered services...
         DiscoveryListener discoveryListener = this.discoveryListener.get();
         if(discoveryListener!=null) {
             Set<String> activeServices = doLookup(updateInterval*3);
             // If there is error talking the the central server, then activeServices == null
             if( activeServices !=null ) {
                 synchronized(discoveredServices) {

                     HashSet<String> removedServices = new HashSet<String>(discoveredServices.keySet());
                     removedServices.removeAll(activeServices);

                     HashSet<String> addedServices = new HashSet<String>(activeServices);
                     addedServices.removeAll(discoveredServices.keySet());
                     addedServices.removeAll(removedServices);

                     for (String service : addedServices) {
                         SimpleDiscoveryEvent e = new SimpleDiscoveryEvent(service);
                         discoveredServices.put(service, e);
                         discoveryListener.onServiceAdd(e);
                     }

                     for (String service : removedServices) {
                     	SimpleDiscoveryEvent e = discoveredServices.remove(service);
                     	if( e !=null ) {
                     		e.removed.set(true);
                     	}
                         discoveryListener.onServiceRemove(e);
                     }
                 }
             }
         }
     }

     public void stop() throws Exception {
         if( startCounter.decrementAndGet()==0 ) {
             running.set(false);
             if( thread!=null ) {
                 thread.join(updateInterval*3);
                 thread=null;
             }
             if( jetty!=null ) {
                 jetty.stop();
                 jetty = null;
             }
         }
     }

     public String getRegistryURL() {
         return registryURL;
     }

     public void setRegistryURL(String discoveryRegistryURL) {
         this.registryURL = discoveryRegistryURL;
     }

     public long getUpdateInterval() {
         return updateInterval;
     }

     public void setUpdateInterval(long updateInterval) {
         this.updateInterval = updateInterval;
     }

     public boolean isStartEmbeddRegistry() {
         return startEmbeddRegistry;
     }

     public void setStartEmbeddRegistry(boolean startEmbeddRegistry) {
         this.startEmbeddRegistry = startEmbeddRegistry;
     }

 }
	/**
	* 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.activemq.transport.discovery.http;

	import java.io.IOException;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Map;
	import java.util.Scanner;
	import java.util.Set;
	import java.util.concurrent.atomic.AtomicBoolean;
	import java.util.concurrent.atomic.AtomicInteger;
	import java.util.concurrent.atomic.AtomicReference;

	import org.apache.activemq.Service;
	import org.apache.activemq.command.DiscoveryEvent;
	import org.apache.activemq.transport.discovery.DiscoveryAgent;
	import org.apache.activemq.transport.discovery.DiscoveryListener;
	import org.apache.activemq.util.IntrospectionSupport;
	import org.apache.commons.httpclient.HttpClient;
	import org.apache.commons.httpclient.methods.DeleteMethod;
	import org.apache.commons.httpclient.methods.GetMethod;
	import org.apache.commons.httpclient.methods.PutMethod;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	public class HTTPDiscoveryAgent implements DiscoveryAgent {

	private static final Logger LOG = LoggerFactory.getLogger(HTTPDiscoveryAgent.class);

	private String registryURL = "http://localhost:8080/discovery-registry/default";
	private HttpClient httpClient = new HttpClient();
	private AtomicBoolean running=new AtomicBoolean();
	private final AtomicReference<DiscoveryListener> discoveryListener = new AtomicReference<DiscoveryListener>();
	private final HashSet<String> registeredServices = new HashSet<String>();
	private final HashMap<String, SimpleDiscoveryEvent> discoveredServices = new HashMap<String, SimpleDiscoveryEvent>();
	private Thread thread;
	private long updateInterval = 1000*10;
	private String brokerName;
	private boolean startEmbeddRegistry=false;
	private Service jetty;
	private AtomicInteger startCounter=new AtomicInteger(0);


	private long initialReconnectDelay = 1000;
	private long maxReconnectDelay = 1000 * 30;
	private long backOffMultiplier = 2;
	private boolean useExponentialBackOff=true;
	private int maxReconnectAttempts;
	private final Object sleepMutex = new Object();
	private long minConnectTime = 5000;

	class SimpleDiscoveryEvent extends DiscoveryEvent {

	private int connectFailures;
	private long reconnectDelay = initialReconnectDelay;
	private long connectTime = System.currentTimeMillis();
	private AtomicBoolean failed = new AtomicBoolean(false);
	private AtomicBoolean removed = new AtomicBoolean(false);

	public SimpleDiscoveryEvent(String service) {
	super(service);
	}

	}


	public String getGroup() {
	return null;
	}

	public void registerService(String service) throws IOException {
	synchronized(registeredServices) {
	registeredServices.add(service);
	}
	doRegister(service);
	}

	synchronized private void doRegister(String service) {
	String url = registryURL;
	try {
	PutMethod method = new PutMethod(url);
	// method.setParams(createParams());
	method.setRequestHeader("service", service);
	int responseCode = httpClient.executeMethod(method);
	LOG.debug("PUT to "+url+" got a "+responseCode);
	} catch (Exception e) {
	LOG.debug("PUT to "+url+" failed with: "+e);
	}
	}

	synchronized private void doUnRegister(String service) {
	String url = registryURL;
	try {
	DeleteMethod method = new DeleteMethod(url);
	// method.setParams(createParams());
	method.setRequestHeader("service", service);
	int responseCode = httpClient.executeMethod(method);
	LOG.debug("DELETE to "+url+" got a "+responseCode);
	} catch (Exception e) {
	LOG.debug("DELETE to "+url+" failed with: "+e);
	}
	}

	// private HttpMethodParams createParams() {
	// HttpMethodParams params = new HttpMethodParams();
	// params.setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(0,false));
	// return params;
	// }

	synchronized private Set<String> doLookup(long freshness) {
	String url = registryURL+"?freshness="+freshness;
	try {
	GetMethod method = new GetMethod(url);
	// method.setParams(createParams());
	int responseCode = httpClient.executeMethod(method);
	LOG.debug("GET to "+url+" got a "+responseCode);
	if( responseCode == 200 ) {
	Set<String> rc = new HashSet<String>();
	Scanner scanner = new Scanner(method.getResponseBodyAsStream());
	while( scanner.hasNextLine() ) {
	String service = scanner.nextLine();
	if( service.trim().length() != 0 ) {
	rc.add(service);
	}
	}
	return rc;
	} else {
	LOG.debug("GET to "+url+" failed with response code: "+responseCode);
	return null;
	}
	} catch (Exception e) {
	LOG.debug("GET to "+url+" failed with: "+e);
	return null;
	}
	}

	public void serviceFailed(DiscoveryEvent devent) throws IOException {

	final SimpleDiscoveryEvent event = (SimpleDiscoveryEvent)devent;
	if (event.failed.compareAndSet(false, true)) {
	discoveryListener.get().onServiceRemove(event);
	if(!event.removed.get()) {
	// Setup a thread to re-raise the event...
	Thread thread = new Thread() {
	public void run() {

	// We detect a failed connection attempt because the service
	// fails right away.
	if (event.connectTime + minConnectTime > System.currentTimeMillis()) {
	LOG.debug("Failure occured soon after the discovery event was generated. It will be clasified as a connection failure: "+event);

	event.connectFailures++;

	if (maxReconnectAttempts > 0 && event.connectFailures >= maxReconnectAttempts) {
	LOG.debug("Reconnect attempts exceeded "+maxReconnectAttempts+" tries. Reconnecting has been disabled.");
	return;
	}

	synchronized (sleepMutex) {
	try {
	if (!running.get() \|\| event.removed.get()) {
	return;
	}
	LOG.debug("Waiting "+event.reconnectDelay+" ms before attepting to reconnect.");
	sleepMutex.wait(event.reconnectDelay);
	} catch (InterruptedException ie) {
	Thread.currentThread().interrupt();
	return;
	}
	}

	if (!useExponentialBackOff) {
	event.reconnectDelay = initialReconnectDelay;
	} else {
	// Exponential increment of reconnect delay.
	event.reconnectDelay *= backOffMultiplier;
	if (event.reconnectDelay > maxReconnectDelay) {
	event.reconnectDelay = maxReconnectDelay;
	}
	}

	} else {
	event.connectFailures = 0;
	event.reconnectDelay = initialReconnectDelay;
	}

	if (!running.get() \|\| event.removed.get()) {
	return;
	}

	event.connectTime = System.currentTimeMillis();
	event.failed.set(false);
	discoveryListener.get().onServiceAdd(event);
	}
	};
	thread.setDaemon(true);
	thread.start();
	}
	}
	}


	public void setBrokerName(String brokerName) {
	this.brokerName = brokerName;
	}

	public void setDiscoveryListener(DiscoveryListener discoveryListener) {
	this.discoveryListener.set(discoveryListener);
	}

	public void setGroup(String group) {
	}

	public void start() throws Exception {
	if( startCounter.addAndGet(1)==1 ) {
	if( startEmbeddRegistry ) {
	jetty = createEmbeddedJettyServer();
	Map props = new HashMap();
	props.put("agent", this);
	IntrospectionSupport.setProperties(jetty, props);
	jetty.start();
	}

	running.set(true);
	thread = new Thread("HTTPDiscovery Agent") {
	@Override
	public void run() {
	while(running.get()) {
	try {
	update();
	Thread.sleep(updateInterval);
	} catch (InterruptedException e) {
	return;
	}
	}
	}
	};
	thread.setDaemon(true);
	thread.start();
	}
	}

	/**
	* Create the EmbeddedJettyServer instance via reflection so that we can avoid a hard runtime dependency on
	* jetty.
	*
	* @return
	* @throws Exception
	*/
	private Service createEmbeddedJettyServer() throws Exception {
	Class clazz = HTTPDiscoveryAgent.class.getClassLoader().loadClass("org.apache.activemq.transport.discovery.http.EmbeddedJettyServer");
	return (Service)clazz.newInstance();
	}

	private void update() {
	// Register all our services...
	synchronized(registeredServices) {
	for (String service : registeredServices) {
	doRegister(service);
	}
	}

	// Find new registered services...
	DiscoveryListener discoveryListener = this.discoveryListener.get();
	if(discoveryListener!=null) {
	Set<String> activeServices = doLookup(updateInterval*3);
	// If there is error talking the the central server, then activeServices == null
	if( activeServices !=null ) {
	synchronized(discoveredServices) {

	HashSet<String> removedServices = new HashSet<String>(discoveredServices.keySet());
	removedServices.removeAll(activeServices);

	HashSet<String> addedServices = new HashSet<String>(activeServices);
	addedServices.removeAll(discoveredServices.keySet());
	addedServices.removeAll(removedServices);

	for (String service : addedServices) {
	SimpleDiscoveryEvent e = new SimpleDiscoveryEvent(service);
	discoveredServices.put(service, e);
	discoveryListener.onServiceAdd(e);
	}

	for (String service : removedServices) {
	SimpleDiscoveryEvent e = discoveredServices.remove(service);
	if( e !=null ) {
	e.removed.set(true);
	}
	discoveryListener.onServiceRemove(e);
	}
	}
	}
	}
	}

	public void stop() throws Exception {
	if( startCounter.decrementAndGet()==0 ) {
	running.set(false);
	if( thread!=null ) {
	thread.join(updateInterval*3);
	thread=null;
	}
	if( jetty!=null ) {
	jetty.stop();
	jetty = null;
	}
	}
	}

	public String getRegistryURL() {
	return registryURL;
	}

	public void setRegistryURL(String discoveryRegistryURL) {
	this.registryURL = discoveryRegistryURL;
	}

	public long getUpdateInterval() {
	return updateInterval;
	}

	public void setUpdateInterval(long updateInterval) {
	this.updateInterval = updateInterval;
	}

	public boolean isStartEmbeddRegistry() {
	return startEmbeddRegistry;
	}

	public void setStartEmbeddRegistry(boolean startEmbeddRegistry) {
	this.startEmbeddRegistry = startEmbeddRegistry;
	}

	}