Renaming Partition{Service, Manager, Event} to IntentPartition{Service, Manager, Event} to better disambiguate between another PartitionService that is responsible for managing datastore partitions
Change-Id: I74d311ae991fb241563a1475ea74a625d8069142
diff --git a/core/store/dist/src/main/java/org/onosproject/store/intent/impl/IntentPartitionManager.java b/core/store/dist/src/main/java/org/onosproject/store/intent/impl/IntentPartitionManager.java
new file mode 100644
index 0000000..565c6cf
--- /dev/null
+++ b/core/store/dist/src/main/java/org/onosproject/store/intent/impl/IntentPartitionManager.java
@@ -0,0 +1,243 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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 org.onosproject.store.intent.impl;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.cluster.ClusterEvent;
+import org.onosproject.cluster.ClusterEventListener;
+import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.ControllerNode;
+import org.onosproject.cluster.Leadership;
+import org.onosproject.cluster.LeadershipEvent;
+import org.onosproject.cluster.LeadershipEventListener;
+import org.onosproject.cluster.LeadershipService;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.event.EventDeliveryService;
+import org.onosproject.event.ListenerRegistry;
+import org.onosproject.net.intent.Key;
+import org.onosproject.net.intent.IntentPartitionEvent;
+import org.onosproject.net.intent.IntentPartitionEventListener;
+import org.onosproject.net.intent.IntentPartitionService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.Collectors;
+
+/**
+ * Manages the assignment of intent keyspace partitions to instances.
+ */
+@Component(immediate = true)
+@Service
+public class IntentPartitionManager implements IntentPartitionService {
+
+ private static final Logger log = LoggerFactory.getLogger(IntentPartitionManager.class);
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ protected LeadershipService leadershipService;
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ protected ClusterService clusterService;
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ protected EventDeliveryService eventDispatcher;
+
+ protected final AtomicBoolean rebalanceScheduled = new AtomicBoolean(false);
+
+ static final int NUM_PARTITIONS = 14;
+ private static final int BACKOFF_TIME = 2;
+ private static final int CHECK_PARTITION_BALANCE_PERIOD_SEC = 10;
+ private static final int RETRY_AFTER_DELAY_SEC = 5;
+
+ private static final String ELECTION_PREFIX = "intent-partition-";
+
+ private ListenerRegistry<IntentPartitionEvent, IntentPartitionEventListener> listenerRegistry;
+ private LeadershipEventListener leaderListener = new InternalLeadershipListener();
+ private ClusterEventListener clusterListener = new InternalClusterEventListener();
+
+ private ScheduledExecutorService executor = Executors
+ .newScheduledThreadPool(1);
+
+ @Activate
+ public void activate() {
+ leadershipService.addListener(leaderListener);
+ clusterService.addListener(clusterListener);
+
+ listenerRegistry = new ListenerRegistry<>();
+ eventDispatcher.addSink(IntentPartitionEvent.class, listenerRegistry);
+
+ for (int i = 0; i < NUM_PARTITIONS; i++) {
+ leadershipService.runForLeadership(getPartitionPath(i));
+ }
+
+ executor.scheduleAtFixedRate(() -> scheduleRebalance(0), 0,
+ CHECK_PARTITION_BALANCE_PERIOD_SEC, TimeUnit.SECONDS);
+ }
+
+ @Deactivate
+ public void deactivate() {
+ executor.shutdownNow();
+
+ eventDispatcher.removeSink(IntentPartitionEvent.class);
+ leadershipService.removeListener(leaderListener);
+ clusterService.removeListener(clusterListener);
+ }
+
+ /**
+ * Sets the specified executor to be used for scheduling background tasks.
+ *
+ * @param executor scheduled executor service for background tasks
+ * @return this PartitionManager
+ */
+ public IntentPartitionManager withScheduledExecutor(ScheduledExecutorService executor) {
+ this.executor = executor;
+ return this;
+ }
+
+ private String getPartitionPath(int i) {
+ return ELECTION_PREFIX + i;
+ }
+
+ private String getPartitionPath(PartitionId id) {
+ return getPartitionPath(id.value());
+ }
+
+ private PartitionId getPartitionForKey(Key intentKey) {
+ int partition = Math.abs((int) intentKey.hash()) % NUM_PARTITIONS;
+ //TODO investigate Guava consistent hash method
+ // ... does it add significant computational complexity? is it worth it?
+ //int partition = consistentHash(intentKey.hash(), NUM_PARTITIONS);
+ PartitionId id = new PartitionId(partition);
+ return id;
+ }
+
+ @Override
+ public boolean isMine(Key intentKey) {
+ return Objects.equals(leadershipService.getLeader(getPartitionPath(getPartitionForKey(intentKey))),
+ clusterService.getLocalNode().id());
+ }
+
+ @Override
+ public NodeId getLeader(Key intentKey) {
+ return leadershipService.getLeader(getPartitionPath(getPartitionForKey(intentKey)));
+ }
+
+ @Override
+ public void addListener(IntentPartitionEventListener listener) {
+ listenerRegistry.addListener(listener);
+ }
+
+ @Override
+ public void removeListener(IntentPartitionEventListener listener) {
+ listenerRegistry.removeListener(listener);
+ }
+
+ protected void doRebalance() {
+ rebalanceScheduled.set(false);
+ try {
+ rebalance();
+ } catch (Exception e) {
+ log.warn("Exception caught during rebalance task. Will retry in " + RETRY_AFTER_DELAY_SEC + " seconds", e);
+ scheduleRebalance(RETRY_AFTER_DELAY_SEC);
+ }
+ }
+
+ /**
+ * Determine whether we have more than our fair share of partitions, and if
+ * so, relinquish leadership of some of them for a little while to let
+ * other instances take over.
+ */
+ private void rebalance() {
+ int activeNodes = (int) clusterService.getNodes()
+ .stream()
+ .filter(node -> ControllerNode.State.ACTIVE == clusterService.getState(node.id()))
+ .count();
+
+ int myShare = (int) Math.ceil((double) NUM_PARTITIONS / activeNodes);
+
+ List<Leadership> myPartitions = leadershipService.getLeaderBoard().values()
+ .stream()
+ .filter(l -> clusterService.getLocalNode().id().equals(l.leader()))
+ .filter(l -> l.topic().startsWith(ELECTION_PREFIX))
+ .collect(Collectors.toList());
+
+ int relinquish = myPartitions.size() - myShare;
+
+ if (relinquish <= 0) {
+ return;
+ }
+
+ for (int i = 0; i < relinquish; i++) {
+ String topic = myPartitions.get(i).topic();
+ leadershipService.withdraw(topic);
+
+ executor.schedule(() -> recontest(topic),
+ BACKOFF_TIME, TimeUnit.SECONDS);
+ }
+ }
+
+ private void scheduleRebalance(int afterDelaySec) {
+ if (rebalanceScheduled.compareAndSet(false, true)) {
+ executor.schedule(this::doRebalance, afterDelaySec, TimeUnit.SECONDS);
+ }
+ }
+
+ /**
+ * Try and recontest for leadership of a partition.
+ *
+ * @param path topic name to recontest
+ */
+ private void recontest(String path) {
+ leadershipService.runForLeadership(path);
+ }
+
+ private final class InternalLeadershipListener implements LeadershipEventListener {
+
+ @Override
+ public void event(LeadershipEvent event) {
+ Leadership leadership = event.subject();
+
+ if (Objects.equals(leadership.leader(), clusterService.getLocalNode().id()) &&
+ leadership.topic().startsWith(ELECTION_PREFIX)) {
+
+ // See if we need to let some partitions go
+ scheduleRebalance(0);
+
+ eventDispatcher.post(new IntentPartitionEvent(IntentPartitionEvent.Type.LEADER_CHANGED,
+ leadership.topic()));
+ }
+ }
+ }
+
+ private final class InternalClusterEventListener implements
+ ClusterEventListener {
+
+ @Override
+ public void event(ClusterEvent event) {
+ scheduleRebalance(0);
+ }
+ }
+}