/* * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved. * Copyright (c) 2015 Brocade Communications Systems, Inc. and others. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ package org.opendaylight.controller.cluster.raft; import akka.actor.ActorRef; import akka.actor.ActorSelection; import akka.actor.PoisonPill; import akka.japi.Procedure; import com.google.common.annotations.VisibleForTesting; import com.google.common.base.Objects; import com.google.common.base.Optional; import com.google.common.base.Supplier; import com.google.common.collect.Lists; import java.io.Serializable; import java.util.Collection; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.concurrent.TimeUnit; import javax.annotation.Nonnull; import org.apache.commons.lang3.time.DurationFormatUtils; import org.opendaylight.controller.cluster.DataPersistenceProvider; import org.opendaylight.controller.cluster.DelegatingPersistentDataProvider; import org.opendaylight.controller.cluster.NonPersistentDataProvider; import org.opendaylight.controller.cluster.PersistentDataProvider; import org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActor; import org.opendaylight.controller.cluster.notifications.LeaderStateChanged; import org.opendaylight.controller.cluster.notifications.RoleChanged; import org.opendaylight.controller.cluster.raft.base.messages.ApplyJournalEntries; import org.opendaylight.controller.cluster.raft.base.messages.ApplyState; import org.opendaylight.controller.cluster.raft.base.messages.InitiateCaptureSnapshot; import org.opendaylight.controller.cluster.raft.base.messages.LeaderTransitioning; import org.opendaylight.controller.cluster.raft.base.messages.Replicate; import org.opendaylight.controller.cluster.raft.base.messages.SwitchBehavior; import org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader; import org.opendaylight.controller.cluster.raft.behaviors.DelegatingRaftActorBehavior; import org.opendaylight.controller.cluster.raft.behaviors.Follower; import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior; import org.opendaylight.controller.cluster.raft.client.messages.FindLeader; import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply; import org.opendaylight.controller.cluster.raft.client.messages.FollowerInfo; import org.opendaylight.controller.cluster.raft.client.messages.GetOnDemandRaftState; import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState; import org.opendaylight.controller.cluster.raft.client.messages.Shutdown; import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * RaftActor encapsulates a state machine that needs to be kept synchronized * in a cluster. It implements the RAFT algorithm as described in the paper * * In Search of an Understandable Consensus Algorithm *
* RaftActor has 3 states and each state has a certain behavior associated * with it. A Raft actor can behave as, ** This is to account for situations where a we know that a peer * exists but we do not know an address up-front. This may also be used in * situations where a known peer starts off in a different location and we * need to change it's address *
* Note that if the peerId does not match the list of peers passed to
* this actor during construction an IllegalStateException will be thrown.
*
* @param peerId
* @param peerAddress
*/
protected void setPeerAddress(String peerId, String peerAddress){
context.setPeerAddress(peerId, peerAddress);
}
/**
* The applyState method will be called by the RaftActor when some data
* needs to be applied to the actor's state
*
* @param clientActor A reference to the client who sent this message. This
* is the same reference that was passed to persistData
* by the derived actor. clientActor may be null when
* the RaftActor is behaving as a follower or during
* recovery.
* @param identifier The identifier of the persisted data. This is also
* the same identifier that was passed to persistData by
* the derived actor. identifier may be null when
* the RaftActor is behaving as a follower or during
* recovery
* @param data A piece of data that was persisted by the persistData call.
* This should NEVER be null.
*/
protected abstract void applyState(ActorRef clientActor, String identifier,
Object data);
/**
* Returns the RaftActorRecoveryCohort to participate in persistence recovery.
*/
@Nonnull
protected abstract RaftActorRecoveryCohort getRaftActorRecoveryCohort();
/**
* This method is called when recovery is complete.
*/
protected abstract void onRecoveryComplete();
/**
* Returns the RaftActorSnapshotCohort to participate in persistence recovery.
*/
@Nonnull
protected abstract RaftActorSnapshotCohort getRaftActorSnapshotCohort();
/**
* This method will be called by the RaftActor when the state of the
* RaftActor changes. The derived actor can then use methods like
* isLeader or getLeader to do something useful
*/
protected abstract void onStateChanged();
/**
* Notifier Actor for this RaftActor to notify when a role change happens
* @return ActorRef - ActorRef of the notifier or Optional.absent if none.
*/
protected abstract Optional
* The default implementation immediately runs the operation.
*
* @param operation the operation to run
*/
protected void pauseLeader(Runnable operation) {
operation.run();
}
protected void onLeaderChanged(String oldLeader, String newLeader){};
private String getLeaderAddress(){
if(isLeader()){
return getSelf().path().toString();
}
String leaderId = currentBehavior.getLeaderId();
if (leaderId == null) {
return null;
}
String peerAddress = context.getPeerAddress(leaderId);
if(LOG.isDebugEnabled()) {
LOG.debug("{}: getLeaderAddress leaderId = {} peerAddress = {}",
persistenceId(), leaderId, peerAddress);
}
return peerAddress;
}
protected boolean hasFollowers(){
return getRaftActorContext().hasFollowers();
}
private void captureSnapshot() {
SnapshotManager snapshotManager = context.getSnapshotManager();
if(!snapshotManager.isCapturing()) {
LOG.debug("Take a snapshot of current state. lastReplicatedLog is {} and replicatedToAllIndex is {}",
replicatedLog().last(), currentBehavior.getReplicatedToAllIndex());
snapshotManager.capture(replicatedLog().last(), currentBehavior.getReplicatedToAllIndex());
}
}
/**
* @deprecated Deprecated in favor of {@link org.opendaylight.controller.cluster.raft.base.messages.DeleteEntries}
* whose type for fromIndex is long instead of int. This class was kept for backwards
* compatibility with Helium.
*/
// Suppressing this warning as we can't set serialVersionUID to maintain backwards compatibility.
@SuppressWarnings("serial")
@Deprecated
static class DeleteEntries implements Serializable {
private final int fromIndex;
public DeleteEntries(int fromIndex) {
this.fromIndex = fromIndex;
}
public int getFromIndex() {
return fromIndex;
}
}
/**
* @deprecated Deprecated in favor of non-inner class {@link org.opendaylight.controller.cluster.raft.base.messages.UpdateElectionTerm}
* which has serialVersionUID set. This class was kept for backwards compatibility with Helium.
*/
// Suppressing this warning as we can't set serialVersionUID to maintain backwards compatibility.
@SuppressWarnings("serial")
@Deprecated
static class UpdateElectionTerm implements Serializable {
private final long currentTerm;
private final String votedFor;
public UpdateElectionTerm(long currentTerm, String votedFor) {
this.currentTerm = currentTerm;
this.votedFor = votedFor;
}
public long getCurrentTerm() {
return currentTerm;
}
public String getVotedFor() {
return votedFor;
}
}
private static class BehaviorStateHolder {
private RaftActorBehavior behavior;
private String lastValidLeaderId;
private short leaderPayloadVersion;
void init(RaftActorBehavior behavior) {
this.behavior = behavior;
this.leaderPayloadVersion = behavior != null ? behavior.getLeaderPayloadVersion() : -1;
String behaviorLeaderId = behavior != null ? behavior.getLeaderId() : null;
if(behaviorLeaderId != null) {
this.lastValidLeaderId = behaviorLeaderId;
}
}
RaftActorBehavior getBehavior() {
return behavior;
}
String getLastValidLeaderId() {
return lastValidLeaderId;
}
short getLeaderPayloadVersion() {
return leaderPayloadVersion;
}
}
private class SwitchBehaviorSupplier implements Supplier