/*
* 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.stratos.load.balancer;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.stratos.load.balancer.context.LoadBalancerContext;
import org.apache.stratos.load.balancer.context.LoadBalancerContextUtil;
import org.apache.stratos.messaging.domain.topology.Cluster;
import org.apache.stratos.messaging.domain.topology.Member;
import org.apache.stratos.messaging.domain.topology.MemberStatus;
import org.apache.stratos.messaging.domain.topology.Service;
import org.apache.stratos.messaging.event.Event;
import org.apache.stratos.messaging.event.topology.ClusterRemovedEvent;
import org.apache.stratos.messaging.event.topology.MemberActivatedEvent;
import org.apache.stratos.messaging.event.topology.ServiceRemovedEvent;
import org.apache.stratos.messaging.listener.topology.ClusterRemovedEventListener;
import org.apache.stratos.messaging.listener.topology.CompleteTopologyEventListener;
import org.apache.stratos.messaging.listener.topology.MemberActivatedEventListener;
import org.apache.stratos.messaging.listener.topology.ServiceRemovedEventListener;
import org.apache.stratos.messaging.message.receiver.topology.TopologyEventReceiver;
import org.apache.stratos.messaging.message.receiver.topology.TopologyManager;
/**
* Load balancer topology receiver updates load balancer context according to
* incoming topology events.
*/
public class LoadBalancerTopologyEventReceiver implements Runnable {
private static final Log log = LogFactory.getLog(LoadBalancerTopologyEventReceiver.class);
private TopologyEventReceiver topologyEventReceiver;
private boolean terminated;
public LoadBalancerTopologyEventReceiver() {
this.topologyEventReceiver = new TopologyEventReceiver();
addEventListeners();
}
@Override
public void run() {
Thread thread = new Thread(topologyEventReceiver);
thread.start();
if (log.isInfoEnabled()) {
log.info("Load balancer topology receiver thread started");
}
// Keep the thread live until terminated
while (!terminated) {
try {
Thread.sleep(1000);
} catch (InterruptedException ignore) {
}
}
if (log.isInfoEnabled()) {
log.info("Load balancer topology receiver thread terminated");
}
}
private void addEventListeners() {
// Listen to topology events that affect clusters
topologyEventReceiver.addEventListener(new CompleteTopologyEventListener() {
@Override
protected void onEvent(Event event) {
try {
TopologyManager.acquireReadLock();
for (Service service : TopologyManager.getTopology().getServices()) {
for (Cluster cluster : service.getClusters()) {
if (clusterHasActiveMembers(cluster)) {
LoadBalancerContextUtil.addClusterToLbContext(cluster);
} else {
if (log.isDebugEnabled()) {
log.debug("Cluster does not have any active members");
}
}
}
}
} catch (Exception e) {
log.error("Error processing event", e);
} finally {
TopologyManager.releaseReadLock();
}
}
private boolean clusterHasActiveMembers(Cluster cluster) {
for (Member member : cluster.getMembers()) {
if (member.getStatus() == MemberStatus.Activated) {
return true;
}
}
return false;
}
});
topologyEventReceiver.addEventListener(new MemberActivatedEventListener() {
@Override
protected void onEvent(Event event) {
try {
TopologyManager.acquireReadLock();
// Add cluster to load balancer context when its first member is activated
MemberActivatedEvent memberActivatedEvent = (MemberActivatedEvent) event;
if (LoadBalancerContext.getInstance().getClusterIdClusterMap().containsCluster(memberActivatedEvent.getClusterId())) {
if (log.isDebugEnabled()) {
log.debug(String.format("Cluster exists in load balancer context: [service] %s [cluster] %s",
memberActivatedEvent.getServiceName(), memberActivatedEvent.getClusterId()));
}
return;
}
// Cluster not found in load balancer context, add it
Service service = TopologyManager.getTopology().getService(memberActivatedEvent.getServiceName());
if (service != null) {
Cluster cluster = service.getCluster(memberActivatedEvent.getClusterId());
if (cluster != null) {
LoadBalancerContextUtil.addClusterToLbContext(cluster);
} else {
if (log.isErrorEnabled()) {
log.error(String.format("Cluster not found in topology: [service] %s [cluster] %s",
memberActivatedEvent.getServiceName(), memberActivatedEvent.getClusterId()));
}
}
} else {
if (log.isErrorEnabled()) {
log.error(String.format("Service not found in topology: [service] %s", memberActivatedEvent.getServiceName()));
}
}
} catch (Exception e) {
log.error("Error processing event", e);
} finally {
TopologyManager.releaseReadLock();
}
}
});
topologyEventReceiver.addEventListener(new ClusterRemovedEventListener() {
@Override
protected void onEvent(Event event) {
try {
TopologyManager.acquireReadLock();
// Remove cluster from context
ClusterRemovedEvent clusterRemovedEvent = (ClusterRemovedEvent) event;
Cluster cluster = LoadBalancerContext.getInstance().getClusterIdClusterMap().getCluster(clusterRemovedEvent.getClusterId());
if (cluster != null) {
LoadBalancerContextUtil.removeClusterFromLbContext(cluster.getClusterId());
} else {
if (log.isWarnEnabled()) {
log.warn(String.format("Cluster not found in load balancer context: [service] %s [cluster] %s",
clusterRemovedEvent.getServiceName(), clusterRemovedEvent.getClusterId()));
}
}
} catch (Exception e) {
log.error("Error processing event", e);
} finally {
TopologyManager.releaseReadLock();
}
}
});
topologyEventReceiver.addEventListener(new ServiceRemovedEventListener() {
@Override
protected void onEvent(Event event) {
try {
TopologyManager.acquireReadLock();
// Remove all clusters of given service from context
ServiceRemovedEvent serviceRemovedEvent = (ServiceRemovedEvent) event;
Service service = TopologyManager.getTopology().getService(serviceRemovedEvent.getServiceName());
if (service != null) {
for (Cluster cluster : service.getClusters()) {
LoadBalancerContextUtil.removeClusterFromLbContext(cluster.getClusterId());
}
} else {
if (log.isWarnEnabled()) {
log.warn(String.format("Service not found in topology: [service] %s", serviceRemovedEvent.getServiceName()));
}
}
} catch (Exception e) {
log.error("Error processing event", e);
} finally {
TopologyManager.releaseReadLock();
}
}
});
}
/**
* Terminate load balancer topology receiver thread.
*/
public void terminate() {
topologyEventReceiver.terminate();
terminated = true;
}
}