X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-distributed-datastore%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fdatastore%2Fentityownership%2FEntityOwnershipShard.java;h=8726dc5bd343f203b71ba38b77eb7e0136ad0823;hb=175f38490b56c4b4e0ec356b17b91f887b295da4;hp=230b597f2d42ffde56f5f0aa8b91c9da62470dbe;hpb=9883165b61255af5bfcb060b76b16f69a56b1f82;p=controller.git diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/EntityOwnershipShard.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/EntityOwnershipShard.java index 230b597f2d..8726dc5bd3 100644 --- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/EntityOwnershipShard.java +++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/EntityOwnershipShard.java @@ -7,29 +7,98 @@ */ package org.opendaylight.controller.cluster.datastore.entityownership; -import akka.actor.Props; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.CANDIDATE_NODE_ID; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_ID_NODE_ID; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_ID_QNAME; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_NODE_ID; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_OWNERS_PATH; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_OWNER_NODE_ID; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_OWNER_QNAME; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_TYPES_PATH; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_TYPE_NODE_ID; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.ENTITY_TYPE_QNAME; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.candidateMapEntry; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.candidateNodeKey; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.candidatePath; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.createEntity; +import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.entityOwnersWithCandidate; +import akka.actor.ActorRef; +import akka.actor.ActorSelection; +import akka.actor.Cancellable; +import akka.pattern.Patterns; +import com.google.common.base.Optional; +import com.google.common.base.Preconditions; +import com.google.common.base.Strings; +import java.util.ArrayList; +import java.util.Collection; +import java.util.HashMap; +import java.util.HashSet; import java.util.Map; +import java.util.Set; +import java.util.concurrent.TimeUnit; +import org.opendaylight.controller.cluster.access.concepts.MemberName; import org.opendaylight.controller.cluster.datastore.DatastoreContext; import org.opendaylight.controller.cluster.datastore.Shard; +import org.opendaylight.controller.cluster.datastore.entityownership.messages.CandidateAdded; +import org.opendaylight.controller.cluster.datastore.entityownership.messages.CandidateRemoved; import org.opendaylight.controller.cluster.datastore.entityownership.messages.RegisterCandidateLocal; +import org.opendaylight.controller.cluster.datastore.entityownership.messages.RegisterListenerLocal; +import org.opendaylight.controller.cluster.datastore.entityownership.messages.SelectOwner; +import org.opendaylight.controller.cluster.datastore.entityownership.messages.UnregisterCandidateLocal; +import org.opendaylight.controller.cluster.datastore.entityownership.messages.UnregisterListenerLocal; +import org.opendaylight.controller.cluster.datastore.entityownership.selectionstrategy.EntityOwnerSelectionStrategy; +import org.opendaylight.controller.cluster.datastore.entityownership.selectionstrategy.EntityOwnerSelectionStrategyConfig; import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier; +import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications; +import org.opendaylight.controller.cluster.datastore.messages.PeerDown; +import org.opendaylight.controller.cluster.datastore.messages.PeerUp; import org.opendaylight.controller.cluster.datastore.messages.SuccessReply; -import org.opendaylight.yangtools.yang.model.api.SchemaContext; +import org.opendaylight.controller.cluster.datastore.modification.DeleteModification; +import org.opendaylight.controller.cluster.datastore.modification.MergeModification; +import org.opendaylight.controller.cluster.datastore.modification.WriteModification; +import org.opendaylight.controller.cluster.raft.RaftState; +import org.opendaylight.controller.md.sal.common.api.clustering.Entity; +import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier; +import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild; +import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode; +import org.opendaylight.yangtools.yang.data.api.schema.MapNode; +import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode; +import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes; +import scala.concurrent.Future; +import scala.concurrent.duration.FiniteDuration; /** * Special Shard for EntityOwnership. * * @author Thomas Pantelis */ -public class EntityOwnershipShard extends Shard { +class EntityOwnershipShard extends Shard { + private final MemberName localMemberName; + private final EntityOwnershipShardCommitCoordinator commitCoordinator; + private final EntityOwnershipListenerSupport listenerSupport; + private final Set downPeerMemberNames = new HashSet<>(); + private final Map peerIdToMemberNames = new HashMap<>(); + private final EntityOwnerSelectionStrategyConfig strategyConfig; + private final Map entityToScheduledOwnershipTask = new HashMap<>(); + private final EntityOwnershipStatistics entityOwnershipStatistics; private static DatastoreContext noPersistenceDatastoreContext(DatastoreContext datastoreContext) { return DatastoreContext.newBuilderFrom(datastoreContext).persistent(false).build(); } - protected EntityOwnershipShard(ShardIdentifier name, Map peerAddresses, - DatastoreContext datastoreContext, SchemaContext schemaContext) { - super(name, peerAddresses, noPersistenceDatastoreContext(datastoreContext), schemaContext); + protected EntityOwnershipShard(Builder builder) { + super(builder); + this.localMemberName = builder.localMemberName; + this.commitCoordinator = new EntityOwnershipShardCommitCoordinator(builder.localMemberName, LOG); + this.listenerSupport = new EntityOwnershipListenerSupport(getContext(), persistenceId()); + this.strategyConfig = builder.ownerSelectionStrategyConfig; + this.entityOwnershipStatistics = new EntityOwnershipStatistics(); + this.entityOwnershipStatistics.init(getDataStore()); + + for(String peerId: getRaftActorContext().getPeerIds()) { + ShardIdentifier shardId = ShardIdentifier.fromShardIdString(peerId); + peerIdToMemberNames.put(peerId, shardId.getMemberName()); + } } @Override @@ -38,34 +107,469 @@ public class EntityOwnershipShard extends Shard { } @Override - public void onReceiveCommand(final Object message) throws Exception { + protected void onRecoveryComplete() { + super.onRecoveryComplete(); + + new CandidateListChangeListener(getSelf(), persistenceId()).init(getDataStore()); + new EntityOwnerChangeListener(localMemberName, listenerSupport).init(getDataStore()); + } + + @Override + public void handleNonRaftCommand(final Object message) { if(message instanceof RegisterCandidateLocal) { - onRegisterCandidateLocal((RegisterCandidateLocal)message); - } else { - super.onReceiveCommand(message); + onRegisterCandidateLocal((RegisterCandidateLocal) message); + } else if(message instanceof UnregisterCandidateLocal) { + onUnregisterCandidateLocal((UnregisterCandidateLocal)message); + } else if(message instanceof CandidateAdded){ + onCandidateAdded((CandidateAdded) message); + } else if(message instanceof CandidateRemoved){ + onCandidateRemoved((CandidateRemoved) message); + } else if(message instanceof PeerDown) { + onPeerDown((PeerDown) message); + } else if(message instanceof PeerUp) { + onPeerUp((PeerUp) message); + } else if(message instanceof RegisterListenerLocal) { + onRegisterListenerLocal((RegisterListenerLocal)message); + } else if(message instanceof UnregisterListenerLocal) { + onUnregisterListenerLocal((UnregisterListenerLocal) message); + } else if(message instanceof SelectOwner) { + onSelectOwner((SelectOwner) message); + } else if(!commitCoordinator.handleMessage(message, this)) { + super.handleNonRaftCommand(message); + } + } + + private void onSelectOwner(SelectOwner selectOwner) { + LOG.debug("{}: onSelectOwner: {}", persistenceId(), selectOwner); + + String currentOwner = getCurrentOwner(selectOwner.getEntityPath()); + if(Strings.isNullOrEmpty(currentOwner)) { + String entityType = EntityOwnersModel.entityTypeFromEntityPath(selectOwner.getEntityPath()); + writeNewOwner(selectOwner.getEntityPath(), newOwner(currentOwner, selectOwner.getAllCandidates(), + entityOwnershipStatistics.byEntityType(entityType), + selectOwner.getOwnerSelectionStrategy())); + + Cancellable cancellable = entityToScheduledOwnershipTask.get(selectOwner.getEntityPath()); + if(cancellable != null){ + if(!cancellable.isCancelled()){ + cancellable.cancel(); + } + entityToScheduledOwnershipTask.remove(selectOwner.getEntityPath()); + } } } private void onRegisterCandidateLocal(RegisterCandidateLocal registerCandidate) { + LOG.debug("{}: onRegisterCandidateLocal: {}", persistenceId(), registerCandidate); + + listenerSupport.setHasCandidateForEntity(registerCandidate.getEntity()); + + NormalizedNode entityOwners = entityOwnersWithCandidate(registerCandidate.getEntity().getType(), + registerCandidate.getEntity().getId(), localMemberName.getName()); + commitCoordinator.commitModification(new MergeModification(ENTITY_OWNERS_PATH, entityOwners), this); + + getSender().tell(SuccessReply.INSTANCE, getSelf()); + } + + private void onUnregisterCandidateLocal(UnregisterCandidateLocal unregisterCandidate) { + LOG.debug("{}: onUnregisterCandidateLocal: {}", persistenceId(), unregisterCandidate); + + Entity entity = unregisterCandidate.getEntity(); + listenerSupport.unsetHasCandidateForEntity(entity); + + YangInstanceIdentifier candidatePath = candidatePath(entity.getType(), entity.getId(), localMemberName.getName()); + commitCoordinator.commitModification(new DeleteModification(candidatePath), this); + + getSender().tell(SuccessReply.INSTANCE, getSelf()); + } + + private void onRegisterListenerLocal(final RegisterListenerLocal registerListener) { + LOG.debug("{}: onRegisterListenerLocal: {}", persistenceId(), registerListener); + + listenerSupport.addEntityOwnershipListener(registerListener.getEntityType(), registerListener.getListener()); + getSender().tell(SuccessReply.INSTANCE, getSelf()); + + searchForEntities((entityTypeNode, entityNode) -> { + Optional> possibleType = entityTypeNode.getChild(ENTITY_TYPE_NODE_ID); + String entityType = possibleType.isPresent() ? possibleType.get().getValue().toString() : null; + if (registerListener.getEntityType().equals(entityType)) { + final boolean hasOwner; + final boolean isOwner; + + Optional> possibleOwner = entityNode.getChild(ENTITY_OWNER_NODE_ID); + if (possibleOwner.isPresent()) { + isOwner = localMemberName.getName().equals(possibleOwner.get().getValue().toString()); + hasOwner = true; + } else { + isOwner = false; + hasOwner = false; + } + + Entity entity = new Entity(entityType, + (YangInstanceIdentifier) entityNode.getChild(ENTITY_ID_NODE_ID).get().getValue()); + + listenerSupport.notifyEntityOwnershipListener(entity, false, isOwner, hasOwner, + registerListener.getListener()); + } + }); + } + + private void onUnregisterListenerLocal(UnregisterListenerLocal unregisterListener) { + LOG.debug("{}: onUnregisterListenerLocal: {}", persistenceId(), unregisterListener); + + listenerSupport.removeEntityOwnershipListener(unregisterListener.getEntityType(), unregisterListener.getListener()); + + getSender().tell(SuccessReply.INSTANCE, getSelf()); + } + + void tryCommitModifications(final BatchedModifications modifications) { + if(isLeader()) { + LOG.debug("{}: Committing BatchedModifications {} locally", persistenceId(), modifications.getTransactionID()); + + // Note that it's possible the commit won't get consensus and will timeout and not be applied + // to the state. However we don't need to retry it in that case b/c it will be committed to + // the journal first and, once a majority of followers come back on line and it is replicated, + // it will be applied at that point. + handleBatchedModificationsLocal(modifications, self()); + } else { + final ActorSelection leader = getLeader(); + if (leader != null) { + if(LOG.isDebugEnabled()) { + LOG.debug("{}: Sending BatchedModifications {} to leader {}", persistenceId(), + modifications.getTransactionID(), leader); + } + + Future future = Patterns.ask(leader, modifications, TimeUnit.SECONDS.toMillis( + getDatastoreContext().getShardTransactionCommitTimeoutInSeconds())); + + Patterns.pipe(future, getContext().dispatcher()).pipeTo(getSelf(), ActorRef.noSender()); + } + } + } + + boolean hasLeader() { + return getLeader() != null && !isIsolatedLeader(); + } + + /** + * Determine if we are in jeopardy based on observed RAFT state. + */ + private static boolean inJeopardy(final RaftState state) { + switch (state) { + case Candidate: + case Follower: + case Leader: + return false; + case IsolatedLeader: + return true; + } + throw new IllegalStateException("Unsupported RAFT state " + state); + } + + private void notifyAllListeners() { + searchForEntities((entityTypeNode, entityNode) -> { + Optional> possibleType = entityTypeNode.getChild(ENTITY_TYPE_NODE_ID); + if (possibleType.isPresent()) { + final boolean hasOwner; + final boolean isOwner; + + Optional> possibleOwner = entityNode.getChild(ENTITY_OWNER_NODE_ID); + if (possibleOwner.isPresent()) { + isOwner = localMemberName.getName().equals(possibleOwner.get().getValue().toString()); + hasOwner = true; + } else { + isOwner = false; + hasOwner = false; + } + + Entity entity = new Entity(possibleType.get().getValue().toString(), + (YangInstanceIdentifier) entityNode.getChild(ENTITY_ID_NODE_ID).get().getValue()); + + listenerSupport.notifyEntityOwnershipListeners(entity, isOwner, isOwner, hasOwner); + } + }); + } + + @Override + protected void onStateChanged() { + super.onStateChanged(); + + boolean isLeader = isLeader(); + LOG.debug("{}: onStateChanged: isLeader: {}, hasLeader: {}", persistenceId(), isLeader, hasLeader()); + + // Examine current RAFT state to see if we are in jeopardy, potentially notifying all listeners + final boolean inJeopardy = inJeopardy(getRaftState()); + final boolean wasInJeopardy = listenerSupport.setInJeopardy(inJeopardy); + if (inJeopardy != wasInJeopardy) { + LOG.debug("{}: {} jeopardy state, notifying all listeners", persistenceId(), + inJeopardy ? "entered" : "left"); + notifyAllListeners(); + } + + commitCoordinator.onStateChanged(this, isLeader); + } + + @Override + protected void onLeaderChanged(String oldLeader, String newLeader) { + super.onLeaderChanged(oldLeader, newLeader); + + boolean isLeader = isLeader(); + LOG.debug("{}: onLeaderChanged: oldLeader: {}, newLeader: {}, isLeader: {}", persistenceId(), oldLeader, + newLeader, isLeader); + + if (isLeader) { + + // Clear all existing strategies so that they get re-created when we call createStrategy again + // This allows the strategies to be re-initialized with existing statistics maintained by + // EntityOwnershipStatistics + strategyConfig.clearStrategies(); + + // Remove the candidates for all members that are known to be down. In a cluster which has greater than + // 3 nodes it is possible for a some node beside the leader being down when the leadership transitions + // it makes sense to use this event to remove all the candidates for those downed nodes + for (MemberName downPeerName : downPeerMemberNames) { + removeCandidateFromEntities(downPeerName); + } + } else { + // The leader changed - notify the coordinator to check if pending modifications need to be sent. + // While onStateChanged also does this, this method handles the case where the shard hears from a + // leader and stays in the follower state. In that case no behavior state change occurs. + commitCoordinator.onStateChanged(this, isLeader); + } + } + + private void onCandidateRemoved(CandidateRemoved message) { + LOG.debug("{}: onCandidateRemoved: {}", persistenceId(), message); + + if(isLeader()) { + String currentOwner = getCurrentOwner(message.getEntityPath()); + if(message.getRemovedCandidate().equals(currentOwner) || message.getRemainingCandidates().size() == 0){ + String entityType = EntityOwnersModel.entityTypeFromEntityPath(message.getEntityPath()); + writeNewOwner(message.getEntityPath(), + newOwner(currentOwner, message.getRemainingCandidates(), entityOwnershipStatistics.byEntityType(entityType), + getEntityOwnerElectionStrategy(message.getEntityPath()))); + } + } else { + // We're not the leader. If the removed candidate is our local member then check if we actually + // have a local candidate registered. If we do then we must have been partitioned from the leader + // and the leader removed our candidate since the leader can't tell the difference between a + // temporary network partition and a node's process actually restarted. So, in that case, re-add + // our candidate. + if(localMemberName.getName().equals(message.getRemovedCandidate()) && + listenerSupport.hasCandidateForEntity(createEntity(message.getEntityPath()))) { + LOG.debug("Local candidate member was removed but a local candidate is registered for {}" + + " - adding back local candidate", message.getEntityPath()); + + commitCoordinator.commitModification(new MergeModification( + candidatePath(message.getEntityPath(), localMemberName.getName()), + candidateMapEntry(localMemberName.getName())), this); + } + } + } + + private EntityOwnerSelectionStrategy getEntityOwnerElectionStrategy(YangInstanceIdentifier entityPath) { + final String entityType = EntityOwnersModel.entityTypeFromEntityPath(entityPath); + return strategyConfig.createStrategy(entityType, entityOwnershipStatistics.byEntityType(entityType)); + } + + private void onCandidateAdded(CandidateAdded message) { + if(!isLeader()){ + return; + } + + LOG.debug("{}: onCandidateAdded: {}", persistenceId(), message); + + // Since a node's candidate member is only added by the node itself, we can assume the node is up so + // remove it from the downPeerMemberNames. + downPeerMemberNames.remove(message.getNewCandidate()); + + final String currentOwner = getCurrentOwner(message.getEntityPath()); + final EntityOwnerSelectionStrategy strategy = getEntityOwnerElectionStrategy(message.getEntityPath()); + final String entityType = EntityOwnersModel.entityTypeFromEntityPath(message.getEntityPath()); + + // Available members is all the known peers - the number of peers that are down + self + // So if there are 2 peers and 1 is down then availableMembers will be 2 + final int availableMembers = (peerIdToMemberNames.size() - downPeerMemberNames.size()) + 1; + + LOG.debug("{}: Using strategy {} to select owner, currentOwner = {}", persistenceId(), strategy, currentOwner); + + if(!message.getAllCandidates().contains(currentOwner)){ + if(strategy.getSelectionDelayInMillis() == 0L) { + writeNewOwner(message.getEntityPath(), newOwner(currentOwner, message.getAllCandidates(), + entityOwnershipStatistics.byEntityType(entityType), strategy)); + } else if(message.getAllCandidates().size() == availableMembers) { + LOG.debug("{}: Received the maximum candidates requests : {} writing new owner", + persistenceId(), availableMembers); + cancelOwnerSelectionTask(message.getEntityPath()); + writeNewOwner(message.getEntityPath(), newOwner(currentOwner, message.getAllCandidates(), + entityOwnershipStatistics.byEntityType(entityType), strategy)); + } else { + scheduleOwnerSelection(message.getEntityPath(), message.getAllCandidates(), strategy); + } + } } - public static Props props(final ShardIdentifier name, final Map peerAddresses, - final DatastoreContext datastoreContext, final SchemaContext schemaContext) { - return Props.create(new Creator(name, peerAddresses, datastoreContext, schemaContext)); + private void onPeerDown(PeerDown peerDown) { + LOG.info("{}: onPeerDown: {}", persistenceId(), peerDown); + + MemberName downMemberName = peerDown.getMemberName(); + if(downPeerMemberNames.add(downMemberName) && isLeader()) { + // Remove the down peer as a candidate from all entities. + removeCandidateFromEntities(downMemberName); + } } - private static class Creator extends AbstractShardCreator { - private static final long serialVersionUID = 1L; + private void onPeerUp(PeerUp peerUp) { + LOG.debug("{}: onPeerUp: {}", persistenceId(), peerUp); + + peerIdToMemberNames.put(peerUp.getPeerId(), peerUp.getMemberName()); + downPeerMemberNames.remove(peerUp.getMemberName()); + + // Notify the coordinator to check if pending modifications need to be sent. We do this here + // to handle the case where the leader's peer address isn't now yet when a prior state or + // leader change occurred. + commitCoordinator.onStateChanged(this, isLeader()); + } + + private void removeCandidateFromEntities(final MemberName owner) { + final BatchedModifications modifications = commitCoordinator.newBatchedModifications(); + searchForEntities((entityTypeNode, entityNode) -> { + if (hasCandidate(entityNode, owner)) { + YangInstanceIdentifier entityId = + (YangInstanceIdentifier) entityNode.getIdentifier().getKeyValues().get(ENTITY_ID_QNAME); + YangInstanceIdentifier candidatePath = candidatePath( + entityTypeNode.getIdentifier().getKeyValues().get(ENTITY_TYPE_QNAME).toString(), + entityId, owner.getName()); + + LOG.info("{}: Found entity {}, removing candidate {}, path {}", persistenceId(), entityId, + owner, candidatePath); + + modifications.addModification(new DeleteModification(candidatePath)); + } + }); + + commitCoordinator.commitModifications(modifications, this); + } + + private static boolean hasCandidate(MapEntryNode entity, MemberName candidateName) { + return ((MapNode)entity.getChild(CANDIDATE_NODE_ID).get()).getChild(candidateNodeKey(candidateName.getName())) + .isPresent(); + } + + private void searchForEntities(EntityWalker walker) { + Optional> possibleEntityTypes = getDataStore().readNode(ENTITY_TYPES_PATH); + if(!possibleEntityTypes.isPresent()) { + return; + } + + for(MapEntryNode entityType: ((MapNode) possibleEntityTypes.get()).getValue()) { + Optional> possibleEntities = entityType.getChild(ENTITY_NODE_ID); + if(!possibleEntities.isPresent()) { + // shouldn't happen but handle anyway + continue; + } + + for(MapEntryNode entity: ((MapNode) possibleEntities.get()).getValue()) { + walker.onEntity(entityType, entity); + } + } + } + + private void writeNewOwner(YangInstanceIdentifier entityPath, String newOwner) { + LOG.debug("{}: Writing new owner {} for entity {}", persistenceId(), newOwner, entityPath); + + commitCoordinator.commitModification(new WriteModification(entityPath.node(ENTITY_OWNER_QNAME), + ImmutableNodes.leafNode(ENTITY_OWNER_NODE_ID, newOwner)), this); + } + + /** + * Schedule a new owner selection job. Cancelling any outstanding job if it has not been cancelled. + * + * @param entityPath + * @param allCandidates + */ + public void scheduleOwnerSelection(YangInstanceIdentifier entityPath, Collection allCandidates, + EntityOwnerSelectionStrategy strategy){ + cancelOwnerSelectionTask(entityPath); + + LOG.debug("{}: Scheduling owner selection after {} ms", persistenceId(), strategy.getSelectionDelayInMillis()); + + final Cancellable lastScheduledTask = context().system().scheduler().scheduleOnce( + FiniteDuration.apply(strategy.getSelectionDelayInMillis(), TimeUnit.MILLISECONDS) + , self(), new SelectOwner(entityPath, allCandidates, strategy) + , context().system().dispatcher(), self()); + + entityToScheduledOwnershipTask.put(entityPath, lastScheduledTask); + } + + private void cancelOwnerSelectionTask(YangInstanceIdentifier entityPath){ + final Cancellable lastScheduledTask = entityToScheduledOwnershipTask.get(entityPath); + if(lastScheduledTask != null && !lastScheduledTask.isCancelled()){ + lastScheduledTask.cancel(); + } + } + + private String newOwner(String currentOwner, Collection candidates, Map statistics, EntityOwnerSelectionStrategy ownerSelectionStrategy) { + Collection viableCandidates = getViableCandidates(candidates); + if(viableCandidates.size() == 0){ + return ""; + } + return ownerSelectionStrategy.newOwner(currentOwner, viableCandidates); + } + + private Collection getViableCandidates(Collection candidates) { + Collection viableCandidates = new ArrayList<>(); + + for (String candidate : candidates) { + if (!downPeerMemberNames.contains(candidate)) { + viableCandidates.add(candidate); + } + } + return viableCandidates; + } + + private String getCurrentOwner(YangInstanceIdentifier entityId) { + Optional> optionalEntityOwner = getDataStore().readNode(entityId.node(ENTITY_OWNER_QNAME)); + if(optionalEntityOwner.isPresent()){ + return optionalEntityOwner.get().getValue().toString(); + } + return null; + } + + private static interface EntityWalker { + void onEntity(MapEntryNode entityTypeNode, MapEntryNode entityNode); + } + + public static Builder newBuilder() { + return new Builder(); + } + + static class Builder extends Shard.AbstractBuilder { + private MemberName localMemberName; + private EntityOwnerSelectionStrategyConfig ownerSelectionStrategyConfig; + + protected Builder() { + super(EntityOwnershipShard.class); + } + + Builder localMemberName(MemberName localMemberName) { + checkSealed(); + this.localMemberName = localMemberName; + return this; + } - Creator(final ShardIdentifier name, final Map peerAddresses, - final DatastoreContext datastoreContext, final SchemaContext schemaContext) { - super(name, peerAddresses, datastoreContext, schemaContext); + Builder ownerSelectionStrategyConfig(EntityOwnerSelectionStrategyConfig ownerSelectionStrategyConfig){ + checkSealed(); + this.ownerSelectionStrategyConfig = ownerSelectionStrategyConfig; + return this; } @Override - public Shard create() throws Exception { - return new EntityOwnershipShard(name, peerAddresses, datastoreContext, schemaContext); + protected void verify() { + super.verify(); + Preconditions.checkNotNull(localMemberName, "localMemberName should not be null"); + Preconditions.checkNotNull(ownerSelectionStrategyConfig, "ownerSelectionStrategyConfig should not be null"); } } }