org.opendaylight.controller.cluster.raft.behaviors

Class AbstractLeader

java.lang.Object

org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior

org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader

All Implemented Interfaces:

AutoCloseable, RaftActorBehavior

Direct Known Subclasses:

IsolatedLeader, Leader, PreLeader

public abstract class AbstractLeader
extends AbstractRaftActorBehavior

The behavior of a RaftActor when it is in the Leader state.

Leaders:

• Upon election: send initial empty AppendEntries RPCs (heartbeat) to each server; repeat during idle periods to prevent election timeouts (§5.2)
• If command received from client: append entry to local log, respond after entry applied to state machine (§5.3)
• If last log index ≥ nextIndex for a follower: send AppendEntries RPC with log entries starting at nextIndex
• If successful: update nextIndex and matchIndex for follower (§5.3)
• If AppendEntries fails because of log inconsistency: decrement nextIndex and retry (§5.3)
• If there exists an N such that N > commitIndex, a majority of matchIndex[i] ≥ N, and log[N].term == currentTerm: set commitIndex = N (§5.3, §5.4).

Field Summary

Fields inherited from class org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior

context, log

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractLeader(RaftActorContext context, RaftState state)
protected	AbstractLeader(RaftActorContext context, RaftState state, AbstractLeader initializeFromLeader)

Method Summary

Modifier and Type	Method and Description
void	addFollower(String followerId)
protected void	beforeSendHeartbeat()
void	close()
int	followerLogSize()
FollowerLogInformation	getFollower(String followerId)
Collection<String>	getFollowerIds() Return an immutable collection of follower identifiers.
String	getLeaderId() Returns the id of the leader.
short	getLeaderPayloadVersion() Returns the leader's payload data version.
protected int	getMinIsolatedLeaderPeerCount()
protected RaftActorBehavior	handleAppendEntries(akka.actor.ActorRef sender, AppendEntries appendEntries) Derived classes should not directly handle AppendEntries messages it should let the base class handle it first.
protected RaftActorBehavior	handleAppendEntriesReply(akka.actor.ActorRef sender, AppendEntriesReply appendEntriesReply) Derived classes should not directly handle AppendEntriesReply messages it should let the base class handle it first.
RaftActorBehavior	handleMessage(akka.actor.ActorRef sender, Object message) Handle a message.
protected RaftActorBehavior	handleRequestVoteReply(akka.actor.ActorRef sender, RequestVoteReply requestVoteReply) Derived classes should not directly handle RequestVoteReply messages it should let the base class handle it first.
boolean	initiateCaptureSnapshot(String followerId) Initiates a snapshot capture to install on a follower.
protected boolean	isLeaderIsolated()
String	printFollowerStates()
protected ClientRequestTracker	removeClientRequestTracker(long logIndex) Removes and returns the ClientRequestTracker for the specified log index.
void	removeFollower(String followerId)
protected void	sendAppendEntries(long timeSinceLastActivityIntervalNanos, boolean isHeartbeat)
void	updateMinReplicaCount()

Methods inherited from class org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior

actor, appendEntries, applyLogToStateMachine, canGrantVote, canStartElection, createBehavior, currentTerm, electionDuration, getId, getLogEntryIndex, getLogEntryOrSnapshotTerm, getLogEntryTerm, getMajorityVoteCount, getReplicatedToAllIndex, internalSwitchBehavior, internalSwitchBehavior, lastIndex, lastTerm, logName, performSnapshotWithoutCapture, requestVote, scheduleElection, setReplicatedToAllIndex, state, stopElection, switchBehavior, votedFor

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractLeader

protected AbstractLeader(RaftActorContext context,
                         RaftState state,
                         @Nullable
                         AbstractLeader initializeFromLeader)

AbstractLeader

protected AbstractLeader(RaftActorContext context,
                         RaftState state)

Method Detail

getFollowerIds

public final Collection<String> getFollowerIds()

Return an immutable collection of follower identifiers.

Returns:

Collection of follower IDs

addFollower

public void addFollower(String followerId)

removeFollower

public void removeFollower(String followerId)

updateMinReplicaCount

public void updateMinReplicaCount()

getMinIsolatedLeaderPeerCount

protected int getMinIsolatedLeaderPeerCount()

handleAppendEntries

protected RaftActorBehavior handleAppendEntries(akka.actor.ActorRef sender,
                                                AppendEntries appendEntries)

Description copied from class: AbstractRaftActorBehavior

Derived classes should not directly handle AppendEntries messages it should let the base class handle it first. Once the base class handles the AppendEntries message and does the common actions that are applicable in all RaftState's it will delegate the handling of the AppendEntries message to the derived class to do more state specific handling by calling this method

Specified by:

handleAppendEntries in class AbstractRaftActorBehavior

Parameters:

sender - The actor that sent this message

appendEntries - The AppendEntries message

Returns:

a new behavior if it was changed or the current behavior

handleAppendEntriesReply

protected RaftActorBehavior handleAppendEntriesReply(akka.actor.ActorRef sender,
                                                     AppendEntriesReply appendEntriesReply)

Description copied from class: AbstractRaftActorBehavior

Derived classes should not directly handle AppendEntriesReply messages it should let the base class handle it first. Once the base class handles the AppendEntriesReply message and does the common actions that are applicable in all RaftState's it will delegate the handling of the AppendEntriesReply message to the derived class to do more state specific handling by calling this method

Specified by:

handleAppendEntriesReply in class AbstractRaftActorBehavior

Parameters:

sender - The actor that sent this message

appendEntriesReply - The AppendEntriesReply message

Returns:

a new behavior if it was changed or the current behavior

removeClientRequestTracker

protected ClientRequestTracker removeClientRequestTracker(long logIndex)

Description copied from class: AbstractRaftActorBehavior

Removes and returns the ClientRequestTracker for the specified log index.

Overrides:

removeClientRequestTracker in class AbstractRaftActorBehavior

Parameters:

logIndex - the log index

Returns:

the ClientRequestTracker or null if none available

handleRequestVoteReply

protected RaftActorBehavior handleRequestVoteReply(akka.actor.ActorRef sender,
                                                   RequestVoteReply requestVoteReply)

Description copied from class: AbstractRaftActorBehavior

Derived classes should not directly handle RequestVoteReply messages it should let the base class handle it first. Once the base class handles the RequestVoteReply message and does the common actions that are applicable in all RaftState's it will delegate the handling of the RequestVoteReply message to the derived class to do more state specific handling by calling this method

Specified by:

handleRequestVoteReply in class AbstractRaftActorBehavior

Parameters:

sender - The actor that sent this message

requestVoteReply - The RequestVoteReply message

Returns:

a new behavior if it was changed or the current behavior

beforeSendHeartbeat

protected void beforeSendHeartbeat()

handleMessage

public RaftActorBehavior handleMessage(akka.actor.ActorRef sender,
                                       Object message)

Description copied from interface: RaftActorBehavior

Handle a message. If the processing of the message warrants a state change then a new behavior should be returned otherwise this method should return the current behavior.

Specified by:

handleMessage in interface RaftActorBehavior

Overrides:

handleMessage in class AbstractRaftActorBehavior

Parameters:

sender - The sender of the message

message - A message that needs to be processed

Returns:

The new behavior or current behavior, or null if the message was not handled.

sendAppendEntries

protected void sendAppendEntries(long timeSinceLastActivityIntervalNanos,
                                 boolean isHeartbeat)

initiateCaptureSnapshot

public boolean initiateCaptureSnapshot(String followerId)

Initiates a snapshot capture to install on a follower.

Install Snapshot works as follows 1. Leader initiates the capture snapshot by calling createSnapshot on the RaftActor. 2. On receipt of the CaptureSnapshotReply message, the RaftActor persists the snapshot and makes a call to the Leader's handleMessage with a SendInstallSnapshot message. 3. The Leader obtains and stores the Snapshot from the SendInstallSnapshot message and sends it in chunks to the Follower via InstallSnapshot messages. 4. For each chunk, the Follower sends back an InstallSnapshotReply. 5. On receipt of the InstallSnapshotReply for the last chunk, the Leader marks the install complete for that follower. 6. If another follower requires a snapshot and a snapshot has been collected (via SendInstallSnapshot) then send the existing snapshot in chunks to the follower.

Parameters:

followerId - the id of the follower.

Returns:

true if capture was initiated, false otherwise.

close

public void close()

getLeaderId

public final String getLeaderId()

Description copied from interface: RaftActorBehavior

Returns the id of the leader.

Returns:

the id of the leader or null if not known

getLeaderPayloadVersion

public final short getLeaderPayloadVersion()

Description copied from interface: RaftActorBehavior

Returns the leader's payload data version.

Returns:

a short representing the version

isLeaderIsolated

protected boolean isLeaderIsolated()

printFollowerStates

public String printFollowerStates()

getFollower

public FollowerLogInformation getFollower(String followerId)

followerLogSize

public int followerLogSize()