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* Licensed to the Apache Software Foundation (ASF) under one
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* 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.brooklyn.policy.followthesun;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.brooklyn.api.entity.Entity;
import org.apache.brooklyn.api.location.Location;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.brooklyn.policy.loadbalancing.Movable;
import com.google.common.collect.Iterables;
// TODO: extract interface
public class FollowTheSunStrategy<ContainerType extends Entity, ItemType extends Movable> {
// This is a modified version of the InterGeographyLatencyPolicy (aka Follow-The-Sun) policy from Monterey v3.
// TODO location constraints
private static final Logger LOG = LoggerFactory.getLogger(FollowTheSunStrategy.class);
private final FollowTheSunParameters parameters;
private final FollowTheSunModel<ContainerType,ItemType> model;
private final String name;
public FollowTheSunStrategy(FollowTheSunModel<ContainerType,ItemType> model, FollowTheSunParameters parameters) {
this.model = model;
this.parameters = parameters;
this.name = model.getName();
}
public void rebalance() {
try {
Set<ItemType> items = model.getItems();
Map<ItemType, Map<Location, Double>> directSendsToItemByLocation = model.getDirectSendsToItemByLocation();
for (ItemType item : items) {
String itemName = model.getName(item);
Location activeLocation = model.getItemLocation(item);
ContainerType activeContainer = model.getItemContainer(item);
Map<Location, Double> sendsByLocation = directSendsToItemByLocation.get(item);
if (sendsByLocation == null) sendsByLocation = Collections.emptyMap();
if (parameters.excludedLocations.contains(activeLocation)) {
if (LOG.isTraceEnabled()) LOG.trace("Ignoring segment {} as it is in {}", itemName, activeLocation);
continue;
}
if (!model.isItemMoveable(item)) {
if (LOG.isDebugEnabled()) LOG.debug("POLICY {} skipping any migration of {}, it is not moveable", name, itemName);
continue;
}
if (model.hasActiveMigration(item)) {
LOG.info("POLICY {} skipping any migration of {}, it is involved in an active migration already", name, itemName);
continue;
}
double total = DefaultFollowTheSunModel.sum(sendsByLocation.values());
if (LOG.isTraceEnabled()) LOG.trace("POLICY {} detected {} msgs/sec in {}, split up as: {}", new Object[] {name, total, itemName, sendsByLocation});
Double current = sendsByLocation.get(activeLocation);
if (current == null) current=0d;
List<WeightedObject<Location>> locationsWtd = new ArrayList<WeightedObject<Location>>();
if (total > 0) {
for (Map.Entry<Location, Double> entry : sendsByLocation.entrySet()) {
Location l = entry.getKey();
Double d = entry.getValue();
if (d > current) locationsWtd.add(new WeightedObject<Location>(l, d));
}
}
Collections.sort(locationsWtd);
Collections.reverse(locationsWtd);
double highestMsgRate = -1;
Location highestLocation = null;
ContainerType optimalContainerInHighest = null;
while (!locationsWtd.isEmpty()) {
WeightedObject<Location> weightedObject = locationsWtd.remove(0);
highestMsgRate = weightedObject.getWeight();
highestLocation = weightedObject.getObject();
optimalContainerInHighest = findOptimal(model.getAvailableContainersFor(item, highestLocation));
if (optimalContainerInHighest != null) {
break;
}
}
if (optimalContainerInHighest == null) {
if (LOG.isDebugEnabled()) LOG.debug("POLICY {} detected {} is already in optimal permitted location ({} of {} msgs/sec)", new Object[] {name, itemName, highestMsgRate, total});
continue;
}
double nextHighestMsgRate = -1;
ContainerType optimalContainerInNextHighest = null;
while (!locationsWtd.isEmpty()) {
WeightedObject<Location> weightedObject = locationsWtd.remove(0);
nextHighestMsgRate = weightedObject.getWeight();
Location nextHighestLocation = weightedObject.getObject();
optimalContainerInNextHighest = findOptimal(model.getAvailableContainersFor(item, nextHighestLocation));
if (optimalContainerInNextHighest != null) {
break;
}
}
if (optimalContainerInNextHighest == null) {
nextHighestMsgRate = current;
}
if (parameters.isTriggered(highestMsgRate, total, nextHighestMsgRate, current)) {
LOG.info("POLICY "+name+" detected "+itemName+" should be in location "+highestLocation+" on "+optimalContainerInHighest+" ("+highestMsgRate+" of "+total+" msgs/sec), migrating");
try {
if (activeContainer.equals(optimalContainerInHighest)) {
//shouldn't happen
LOG.warn("POLICY "+name+" detected "+itemName+" should move to "+optimalContainerInHighest+" ("+highestMsgRate+" of "+total+" msgs/sec) but it is already there with "+current+" msgs/sec");
} else {
item.move(optimalContainerInHighest);
model.onItemMoved(item, optimalContainerInHighest);
}
} catch (Exception e) {
LOG.warn("POLICY "+name+" detected "+itemName+" should be on "+optimalContainerInHighest+", but can't move it: "+e, e);
}
} else {
if (LOG.isTraceEnabled()) LOG.trace("POLICY "+name+" detected "+itemName+" need not move to "+optimalContainerInHighest+" ("+highestMsgRate+" of "+total+" msgs/sec not much better than "+current+" at "+activeContainer+")");
}
}
} catch (Exception e) {
LOG.warn("Error in policy "+name+" (ignoring): "+e, e);
}
}
private ContainerType findOptimal(Collection<ContainerType> contenders) {
/*
* TODO should choose the least loaded mediator. Currently chooses first available, and relies
* on a load-balancer to move it again; would be good if these could share decision code so move
* it to the right place immediately. e.g.
* policyUtil.findLeastLoadedMediator(nodesInLocation);
*/
return (contenders.isEmpty() ? null : Iterables.get(contenders, 0));
}
}