*/
package org.opendaylight.controller.cluster.raft;
-import java.util.ArrayList;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-import java.util.Queue;
-import java.util.concurrent.TimeUnit;
import akka.actor.ActorRef;
import akka.actor.ActorSelection;
import akka.actor.Cancellable;
-import org.opendaylight.controller.cluster.raft.FollowerLogInformation.FollowerState;
-import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
+import com.google.common.base.Preconditions;
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.UUID;
+import javax.annotation.Nullable;
import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
+import org.opendaylight.controller.cluster.raft.base.messages.SnapshotComplete;
import org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader;
import org.opendaylight.controller.cluster.raft.messages.AddServer;
import org.opendaylight.controller.cluster.raft.messages.AddServerReply;
+import org.opendaylight.controller.cluster.raft.messages.RemoveServer;
+import org.opendaylight.controller.cluster.raft.messages.RemoveServerReply;
import org.opendaylight.controller.cluster.raft.messages.ServerChangeStatus;
+import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
+import org.opendaylight.controller.cluster.raft.messages.UnInitializedFollowerSnapshotReply;
+import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
-import org.opendaylight.controller.cluster.raft.messages.FollowerCatchUpTimeout;
-import org.opendaylight.controller.cluster.raft.messages.UnInitializedFollowerSnapshotReply;
-import scala.concurrent.duration.FiniteDuration;
/**
* Handles server configuration related messages for a RaftActor.
*/
class RaftActorServerConfigurationSupport {
private static final Logger LOG = LoggerFactory.getLogger(RaftActorServerConfigurationSupport.class);
- private final RaftActorContext context;
- // client follower queue
- private final Queue<CatchupFollowerInfo> followerInfoQueue = new LinkedList<CatchupFollowerInfo>();
- // timeout handle
- private Cancellable followerTimeout = null;
- RaftActorServerConfigurationSupport(RaftActorContext context) {
- this.context = context;
+ private final OperationState IDLE = new Idle();
+
+ private final RaftActor raftActor;
+
+ private final RaftActorContext raftContext;
+
+ private final Queue<ServerOperationContext<?>> pendingOperationsQueue = new LinkedList<>();
+
+ private OperationState currentOperationState = IDLE;
+
+ RaftActorServerConfigurationSupport(RaftActor raftActor) {
+ this.raftActor = raftActor;
+ this.raftContext = raftActor.getRaftActorContext();
}
- boolean handleMessage(Object message, RaftActor raftActor, ActorRef sender) {
+ boolean handleMessage(Object message, ActorRef sender) {
if(message instanceof AddServer) {
- onAddServer((AddServer)message, raftActor, sender);
+ onAddServer((AddServer) message, sender);
return true;
- } else if (message instanceof FollowerCatchUpTimeout){
- FollowerCatchUpTimeout followerTimeout = (FollowerCatchUpTimeout)message;
- // abort follower catchup on timeout
- onFollowerCatchupTimeout(raftActor, sender, followerTimeout.getNewServerId());
+ } else if(message instanceof RemoveServer) {
+ onRemoveServer((RemoveServer) message, sender);
return true;
- } else if (message instanceof UnInitializedFollowerSnapshotReply){
- // snapshot installation is successful
- onUnInitializedFollowerSnapshotReply((UnInitializedFollowerSnapshotReply)message, raftActor,sender);
+ } else if (message instanceof ServerOperationTimeout) {
+ currentOperationState.onServerOperationTimeout((ServerOperationTimeout) message);
return true;
- } else if(message instanceof ApplyState){
- ApplyState applyState = (ApplyState) message;
- Payload data = applyState.getReplicatedLogEntry().getData();
- if( data instanceof ServerConfigurationPayload){
- LOG.info("Server configuration : {} has been replicated to a majority of cluster servers succesfully",
- (ServerConfigurationPayload)data);
- // respond ok to follower
- respondToClient(raftActor, ServerChangeStatus.OK);
- return true;
- }
+ } else if (message instanceof UnInitializedFollowerSnapshotReply) {
+ currentOperationState.onUnInitializedFollowerSnapshotReply((UnInitializedFollowerSnapshotReply) message);
+ return true;
+ } else if(message instanceof ApplyState) {
+ return onApplyState((ApplyState) message);
+ } else if(message instanceof SnapshotComplete) {
+ currentOperationState.onSnapshotComplete();
return false;
} else {
return false;
}
}
- private void onAddServer(AddServer addServer, RaftActor raftActor, ActorRef sender) {
- LOG.debug("onAddServer: {}", addServer);
- if(noLeaderOrForwardedToLeader(addServer, raftActor, sender)) {
- return;
- }
-
- CatchupFollowerInfo followerInfo = new CatchupFollowerInfo(addServer,sender);
- boolean process = !followerInfoQueue.isEmpty();
- followerInfoQueue.add(followerInfo);
- if(process) {
- processAddServer(raftActor);
- }
- }
-
- private void processAddServer(RaftActor raftActor){
- LOG.debug("In processAddServer");
- AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
- AddServer addSrv = followerInfoQueue.peek().getAddServer();
- context.addToPeers(addSrv.getNewServerId(), addSrv.getNewServerAddress());
-
- // if voting member - initialize to VOTING_NOT_INITIALIZED
- FollowerState initialState = addSrv.isVotingMember() ? FollowerState.VOTING_NOT_INITIALIZED :
- FollowerState.NON_VOTING;
- leader.addFollower(addSrv.getNewServerId(), initialState);
-
- // TODO
- // if initialState == FollowerState.VOTING_NOT_INITIALIZED
- // Initiate snapshot via leader.initiateCaptureSnapshot(addServer.getNewServerId())
- // Start a timer to abort the operation after a period of time (maybe 2 times election timeout)
- // Set local instance state and wait for message from the AbstractLeader when install snapshot
- // is done and return now
- // When install snapshot message is received, go to step 1
- // else
- // go to step 2
- //
- // 1) tell AbstractLeader mark the follower as VOTING and recalculate minReplicationCount and
- // minIsolatedLeaderPeerCount
- // 2) persist and replicate ServerConfigurationPayload via
- // raftActor.persistData(sender, uuid, newServerConfigurationPayload)
- // 3) Wait for commit complete via ApplyState message in RaftActor or time it out. In RaftActor,
- // on ApplyState, check if ReplicatedLogEntry payload is ServerConfigurationPayload and call
- // this class.
- //
- if(initialState == FollowerState.VOTING_NOT_INITIALIZED){
- LOG.debug("Leader sending initiate capture snapshot to follower : {}", addSrv.getNewServerId());
- leader.initiateCaptureSnapshot(addSrv.getNewServerId());
- // schedule the catchup timeout timer
- followerTimeout = context.getActorSystem().scheduler()
- .scheduleOnce(new FiniteDuration(((context.getConfigParams().getElectionTimeOutInterval().toMillis()) * 2),
- TimeUnit.MILLISECONDS),
- context.getActor(), new FollowerCatchUpTimeout(addSrv.getNewServerId()),
- context.getActorSystem().dispatcher(), context.getActor());
+ private void onRemoveServer(RemoveServer removeServer, ActorRef sender) {
+ LOG.debug("{}: onRemoveServer: {}, state: {}", raftContext.getId(), removeServer, currentOperationState);
+ if(removeServer.getServerId().equals(raftActor.getLeaderId())){
+ // Removing current leader is not supported yet
+ // TODO: To properly support current leader removal we need to first implement transfer of leadership
+ LOG.debug("Cannot remove {} replica because it is the Leader", removeServer.getServerId());
+ sender.tell(new RemoveServerReply(ServerChangeStatus.NOT_SUPPORTED, raftActor.getLeaderId()), raftActor.getSelf());
+ } else if(!raftContext.getPeerIds().contains(removeServer.getServerId())) {
+ sender.tell(new RemoveServerReply(ServerChangeStatus.DOES_NOT_EXIST, raftActor.getLeaderId()), raftActor.getSelf());
} else {
- LOG.debug("Directly persisting the new server configuration : {}", addSrv.getNewServerId());
- persistNewServerConfiguration(raftActor, followerInfoQueue.peek().getClientRequestor(),
- addSrv.getNewServerId());
+ onNewOperation(new RemoveServerContext(removeServer, raftContext.getPeerAddress(removeServer.getServerId()), sender));
}
}
- private boolean noLeaderOrForwardedToLeader(Object message, RaftActor raftActor, ActorRef sender) {
- if (raftActor.isLeader()) {
- return false;
+ private boolean onApplyState(ApplyState applyState) {
+ Payload data = applyState.getReplicatedLogEntry().getData();
+ if(data instanceof ServerConfigurationPayload) {
+ currentOperationState.onApplyState(applyState);
+ return true;
}
- ActorSelection leader = raftActor.getLeader();
- if (leader != null) {
- LOG.debug("Not leader - forwarding to leader {}", leader);
- leader.forward(message, raftActor.getContext());
+ return false;
+ }
+
+ /**
+ * The algorithm for AddServer is as follows:
+ * <ul>
+ * <li>Add the new server as a peer.</li>
+ * <li>Add the new follower to the leader.</li>
+ * <li>If new server should be voting member</li>
+ * <ul>
+ * <li>Initialize FollowerState to VOTING_NOT_INITIALIZED.</li>
+ * <li>Initiate install snapshot to the new follower.</li>
+ * <li>When install snapshot complete, mark the follower as VOTING and re-calculate majority vote count.</li>
+ * </ul>
+ * <li>Persist and replicate ServerConfigurationPayload with the new server list.</li>
+ * <li>On replication consensus, respond to caller with OK.</li>
+ * </ul>
+ * If the install snapshot times out after a period of 2 * election time out
+ * <ul>
+ * <li>Remove the new server as a peer.</li>
+ * <li>Remove the new follower from the leader.</li>
+ * <li>Respond to caller with TIMEOUT.</li>
+ * </ul>
+ */
+ private void onAddServer(AddServer addServer, ActorRef sender) {
+ LOG.debug("{}: onAddServer: {}, state: {}", raftContext.getId(), addServer, currentOperationState);
+
+ onNewOperation(new AddServerContext(addServer, sender));
+ }
+
+ private void onNewOperation(ServerOperationContext<?> operationContext) {
+ if (raftActor.isLeader()) {
+ currentOperationState.onNewOperation(operationContext);
} else {
- LOG.debug("No leader - returning NO_LEADER AddServerReply");
- sender.tell(new AddServerReply(ServerChangeStatus.NO_LEADER, null), raftActor.self());
+ ActorSelection leader = raftActor.getLeader();
+ if (leader != null) {
+ LOG.debug("{}: Not leader - forwarding to leader {}", raftContext.getId(), leader);
+ leader.forward(operationContext.getOperation(), raftActor.getContext());
+ } else {
+ LOG.debug("{}: No leader - returning NO_LEADER reply", raftContext.getId());
+ operationContext.getClientRequestor().tell(operationContext.newReply(
+ ServerChangeStatus.NO_LEADER, null), raftActor.self());
+ }
}
+ }
+
+ /**
+ * Interface for a server operation FSM state.
+ */
+ private interface OperationState {
+ void onNewOperation(ServerOperationContext<?> operationContext);
+
+ void onServerOperationTimeout(ServerOperationTimeout timeout);
+
+ void onUnInitializedFollowerSnapshotReply(UnInitializedFollowerSnapshotReply reply);
+
+ void onApplyState(ApplyState applyState);
+
+ void onSnapshotComplete();
+ }
- return true;
+ /**
+ * Interface for the initial state for a server operation.
+ */
+ private interface InitialOperationState {
+ void initiate();
}
- private void onUnInitializedFollowerSnapshotReply(UnInitializedFollowerSnapshotReply reply,
- RaftActor raftActor, ActorRef sender){
+ /**
+ * Abstract base class for a server operation FSM state. Handles common behavior for all states.
+ */
+ private abstract class AbstractOperationState implements OperationState {
+ @Override
+ public void onNewOperation(ServerOperationContext<?> operationContext) {
+ // We're currently processing another operation so queue it to be processed later.
+
+ LOG.debug("{}: Server operation already in progress - queueing {}", raftContext.getId(),
+ operationContext.getOperation());
+
+ pendingOperationsQueue.add(operationContext);
+ }
+
+ @Override
+ public void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ LOG.debug("onServerOperationTimeout should not be called in state {}", this);
+ }
+
+ @Override
+ public void onUnInitializedFollowerSnapshotReply(UnInitializedFollowerSnapshotReply reply) {
+ LOG.debug("onUnInitializedFollowerSnapshotReply was called in state {}", this);
+ }
+
+ @Override
+ public void onApplyState(ApplyState applyState) {
+ LOG.debug("onApplyState was called in state {}", this);
+ }
+
+ @Override
+ public void onSnapshotComplete() {
+ }
+
+ protected void persistNewServerConfiguration(ServerOperationContext<?> operationContext){
+ raftContext.setDynamicServerConfigurationInUse();
+ ServerConfigurationPayload payload = raftContext.getPeerServerInfo();
+ LOG.debug("{}: New server configuration : {}", raftContext.getId(), payload.getServerConfig());
+
+ raftActor.persistData(operationContext.getClientRequestor(), operationContext.getContextId(), payload);
+
+ currentOperationState = new Persisting(operationContext, newTimer(new ServerOperationTimeout(operationContext.getServerId())));
- String followerId = reply.getFollowerId();
- AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
- FollowerLogInformation followerLogInformation = leader.getFollower(followerId);
- stopFollowerTimer();
- followerLogInformation.setFollowerState(FollowerState.VOTING);
- leader.updateMinReplicaCountAndMinIsolatedLeaderPeerCount();
- persistNewServerConfiguration(raftActor, sender, followerId);
+ sendReply(operationContext, ServerChangeStatus.OK);
+ }
+
+ protected void operationComplete(ServerOperationContext<?> operationContext, @Nullable ServerChangeStatus replyStatus) {
+ if(replyStatus != null) {
+ sendReply(operationContext, replyStatus);
+ }
+
+ operationContext.operationComplete(raftActor, replyStatus);
+
+ currentOperationState = IDLE;
+
+ ServerOperationContext<?> nextOperation = pendingOperationsQueue.poll();
+ if(nextOperation != null) {
+ RaftActorServerConfigurationSupport.this.onNewOperation(nextOperation);
+ }
+ }
+
+ protected void sendReply(ServerOperationContext<?> operationContext, ServerChangeStatus status) {
+ LOG.debug("{}: Returning {} for operation {}", raftContext.getId(), status, operationContext.getOperation());
+
+ operationContext.getClientRequestor().tell(operationContext.newReply(status, raftActor.getLeaderId()),
+ raftActor.self());
+ }
+
+ Cancellable newTimer(Object message) {
+ return raftContext.getActorSystem().scheduler().scheduleOnce(
+ raftContext.getConfigParams().getElectionTimeOutInterval().$times(2), raftContext.getActor(), message,
+ raftContext.getActorSystem().dispatcher(), raftContext.getActor());
+ }
+
+ @Override
+ public String toString() {
+ return getClass().getSimpleName();
+ }
+ }
+
+ /**
+ * The state when no server operation is in progress. It immediately initiates new server operations.
+ */
+ private class Idle extends AbstractOperationState {
+ @Override
+ public void onNewOperation(ServerOperationContext<?> operationContext) {
+ operationContext.newInitialOperationState(RaftActorServerConfigurationSupport.this).initiate();
+ }
+
+ @Override
+ public void onApplyState(ApplyState applyState) {
+ // Noop - we override b/c ApplyState is called normally for followers in the idle state.
+ }
+ }
+
+ /**
+ * The state when a new server configuration is being persisted and replicated.
+ */
+ private class Persisting extends AbstractOperationState {
+ private final ServerOperationContext<?> operationContext;
+ private final Cancellable timer;
+ private boolean timedOut = false;
+
+ Persisting(ServerOperationContext<?> operationContext, Cancellable timer) {
+ this.operationContext = operationContext;
+ this.timer = timer;
+ }
+
+ @Override
+ public void onApplyState(ApplyState applyState) {
+ // Sanity check - we could get an ApplyState from a previous operation that timed out so make
+ // sure it's meant for us.
+ if(operationContext.getContextId().equals(applyState.getIdentifier())) {
+ LOG.info("{}: {} has been successfully replicated to a majority of followers", raftActor.getId(),
+ applyState.getReplicatedLogEntry().getData());
+
+ timer.cancel();
+ operationComplete(operationContext, null);
+ }
+ }
+
+ @Override
+ public void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ LOG.warn("{}: Timeout occured while replicating the new server configuration for {}", raftContext.getId(),
+ timeout.getServerId());
+
+ timedOut = true;
+
+ // Fail any pending operations
+ ServerOperationContext<?> nextOperation = pendingOperationsQueue.poll();
+ while(nextOperation != null) {
+ sendReply(nextOperation, ServerChangeStatus.PRIOR_REQUEST_CONSENSUS_TIMEOUT);
+ nextOperation = pendingOperationsQueue.poll();
+ }
+ }
+
+ @Override
+ public void onNewOperation(ServerOperationContext<?> operationContext) {
+ if(timedOut) {
+ sendReply(operationContext, ServerChangeStatus.PRIOR_REQUEST_CONSENSUS_TIMEOUT);
+ } else {
+ super.onNewOperation(operationContext);
+ }
+ }
}
- private void persistNewServerConfiguration(RaftActor raftActor, ActorRef sender, String followerId){
- /* get old server configuration list */
- Map<String, String> tempMap = context.getPeerAddresses();
- List<String> cOld = new ArrayList<String>();
- for (Map.Entry<String, String> entry : tempMap.entrySet()) {
- if(!entry.getKey().equals(followerId)){
- cOld.add(entry.getKey());
+ /**
+ * Abstract base class for an AddServer operation state.
+ */
+ private abstract class AddServerState extends AbstractOperationState {
+ private final AddServerContext addServerContext;
+
+ AddServerState(AddServerContext addServerContext) {
+ this.addServerContext = addServerContext;
+ }
+
+ AddServerContext getAddServerContext() {
+ return addServerContext;
+ }
+
+ Cancellable newInstallSnapshotTimer() {
+ return newTimer(new ServerOperationTimeout(addServerContext.getOperation().getNewServerId()));
+ }
+
+ void handleInstallSnapshotTimeout(ServerOperationTimeout timeout) {
+ String serverId = timeout.getServerId();
+
+ LOG.debug("{}: handleInstallSnapshotTimeout for new server {}", raftContext.getId(), serverId);
+
+ // cleanup
+ raftContext.removePeer(serverId);
+
+ boolean isLeader = raftActor.isLeader();
+ if(isLeader) {
+ AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
+ leader.removeFollower(serverId);
}
+
+ operationComplete(getAddServerContext(), isLeader ? ServerChangeStatus.TIMEOUT : ServerChangeStatus.NO_LEADER);
+ }
+
+ }
+
+ /**
+ * The initial state for the AddServer operation. It adds the new follower as a peer and initiates
+ * snapshot capture, if necessary.
+ */
+ private class InitialAddServerState extends AddServerState implements InitialOperationState {
+ InitialAddServerState(AddServerContext addServerContext) {
+ super(addServerContext);
}
- LOG.debug("Cold server configuration : {}", cOld.toString());
- /* get new server configuration list */
- List <String> cNew = new ArrayList<String>(cOld);
- cNew.add(followerId);
- LOG.debug("Cnew server configuration : {}", cNew.toString());
- // construct the peer list
- ServerConfigurationPayload servPayload = new ServerConfigurationPayload(cOld, cNew);
- /* TODO - persist new configuration - CHECK WHETHER USING getId below is correct */
- raftActor.persistData(sender, context.getId(), servPayload);
- }
-
- private void stopFollowerTimer() {
- if (followerTimeout != null && !followerTimeout.isCancelled()) {
- followerTimeout.cancel();
- }
- }
-
- private void onFollowerCatchupTimeout(RaftActor raftActor, ActorRef sender, String serverId){
-
- LOG.debug("onFollowerCatchupTimeout: {}", serverId);
- AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
- // cleanup
- context.removePeer(serverId);
- leader.removeFollower(serverId);
- LOG.warn("onFollowerCatchupTimeout - Timeout occured for server - {} while installing snapshot", serverId);
- respondToClient(raftActor,ServerChangeStatus.TIMEOUT);
- }
-
- private void respondToClient(RaftActor raftActor, ServerChangeStatus result){
-
- int size = followerInfoQueue.size();
-
- // remove the entry from the queue
- CatchupFollowerInfo fInfo = followerInfoQueue.remove();
- // get the sender
- ActorRef toClient = fInfo.getClientRequestor();
-
- toClient.tell(new AddServerReply(result, raftActor.getLeaderId()), raftActor.self());
- LOG.debug("Response returned is {} for server {} ", result, fInfo.getAddServer().getNewServerId());
- if(!followerInfoQueue.isEmpty()){
- processAddServer(raftActor);
- }
- }
-
- // mantain sender actorRef
- private class CatchupFollowerInfo {
- private final AddServer addServer;
+
+ @Override
+ public void initiate() {
+ AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
+ AddServer addServer = getAddServerContext().getOperation();
+
+ LOG.debug("{}: Initiating {}", raftContext.getId(), addServer);
+
+ if(raftContext.getPeerInfo(addServer.getNewServerId()) != null) {
+ operationComplete(getAddServerContext(), ServerChangeStatus.ALREADY_EXISTS);
+ return;
+ }
+
+ VotingState votingState = addServer.isVotingMember() ? VotingState.VOTING_NOT_INITIALIZED :
+ VotingState.NON_VOTING;
+ raftContext.addToPeers(addServer.getNewServerId(), addServer.getNewServerAddress(), votingState);
+
+ leader.addFollower(addServer.getNewServerId());
+
+ if(votingState == VotingState.VOTING_NOT_INITIALIZED){
+ // schedule the install snapshot timeout timer
+ Cancellable installSnapshotTimer = newInstallSnapshotTimer();
+ if(leader.initiateCaptureSnapshot(addServer.getNewServerId())) {
+ LOG.debug("{}: Initiating capture snapshot for new server {}", raftContext.getId(),
+ addServer.getNewServerId());
+
+ currentOperationState = new InstallingSnapshot(getAddServerContext(), installSnapshotTimer);
+ } else {
+ LOG.debug("{}: Snapshot already in progress - waiting for completion", raftContext.getId());
+
+ currentOperationState = new WaitingForPriorSnapshotComplete(getAddServerContext(),
+ installSnapshotTimer);
+ }
+ } else {
+ LOG.debug("{}: New follower is non-voting - directly persisting new server configuration",
+ raftContext.getId());
+
+ persistNewServerConfiguration(getAddServerContext());
+ }
+ }
+ }
+
+ /**
+ * The AddServer operation state for when the catch-up snapshot is being installed. It handles successful
+ * reply or timeout.
+ */
+ private class InstallingSnapshot extends AddServerState {
+ private final Cancellable installSnapshotTimer;
+
+ InstallingSnapshot(AddServerContext addServerContext, Cancellable installSnapshotTimer) {
+ super(addServerContext);
+ this.installSnapshotTimer = Preconditions.checkNotNull(installSnapshotTimer);
+ }
+
+ @Override
+ public void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ handleInstallSnapshotTimeout(timeout);
+
+ LOG.warn("{}: Timeout occured for new server {} while installing snapshot", raftContext.getId(),
+ timeout.getServerId());
+ }
+
+ @Override
+ public void onUnInitializedFollowerSnapshotReply(UnInitializedFollowerSnapshotReply reply) {
+ LOG.debug("{}: onUnInitializedFollowerSnapshotReply: {}", raftContext.getId(), reply);
+
+ String followerId = reply.getFollowerId();
+
+ // Sanity check to guard against receiving an UnInitializedFollowerSnapshotReply from a prior
+ // add server operation that timed out.
+ if(getAddServerContext().getOperation().getNewServerId().equals(followerId) && raftActor.isLeader()) {
+ AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
+ raftContext.getPeerInfo(followerId).setVotingState(VotingState.VOTING);
+ leader.updateMinReplicaCount();
+
+ persistNewServerConfiguration(getAddServerContext());
+
+ installSnapshotTimer.cancel();
+ } else {
+ LOG.debug("{}: Dropping UnInitializedFollowerSnapshotReply for server {}: {}",
+ raftContext.getId(), followerId,
+ !raftActor.isLeader() ? "not leader" : "server Id doesn't match");
+ }
+ }
+ }
+
+ /**
+ * The AddServer operation state for when there is a snapshot already in progress. When the current
+ * snapshot completes, it initiates an install snapshot.
+ */
+ private class WaitingForPriorSnapshotComplete extends AddServerState {
+ private final Cancellable snapshotTimer;
+
+ WaitingForPriorSnapshotComplete(AddServerContext addServerContext, Cancellable snapshotTimer) {
+ super(addServerContext);
+ this.snapshotTimer = Preconditions.checkNotNull(snapshotTimer);
+ }
+
+ @Override
+ public void onSnapshotComplete() {
+ LOG.debug("{}: onSnapshotComplete", raftContext.getId());
+
+ if(!raftActor.isLeader()) {
+ LOG.debug("{}: No longer the leader", raftContext.getId());
+ return;
+ }
+
+ AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
+ if(leader.initiateCaptureSnapshot(getAddServerContext().getOperation().getNewServerId())) {
+ LOG.debug("{}: Initiating capture snapshot for new server {}", raftContext.getId(),
+ getAddServerContext().getOperation().getNewServerId());
+
+ currentOperationState = new InstallingSnapshot(getAddServerContext(),
+ newInstallSnapshotTimer());
+
+ snapshotTimer.cancel();
+ }
+ }
+
+ @Override
+ public void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ handleInstallSnapshotTimeout(timeout);
+
+ LOG.warn("{}: Timeout occured for new server {} while waiting for prior snapshot to complete",
+ raftContext.getId(), timeout.getServerId());
+ }
+ }
+
+ /**
+ * Stores context information for a server operation.
+ *
+ * @param <T> the operation type
+ */
+ private static abstract class ServerOperationContext<T> {
+ private final T operation;
private final ActorRef clientRequestor;
+ private final String contextId;
+
+ ServerOperationContext(T operation, ActorRef clientRequestor){
+ this.operation = operation;
+ this.clientRequestor = clientRequestor;
+ contextId = UUID.randomUUID().toString();
+ }
- CatchupFollowerInfo(AddServer addSrv, ActorRef cliReq){
- addServer = addSrv;
- clientRequestor = cliReq;
+ String getContextId() {
+ return contextId;
}
- public AddServer getAddServer(){
- return addServer;
+
+ T getOperation() {
+ return operation;
}
- public ActorRef getClientRequestor(){
+
+ ActorRef getClientRequestor() {
return clientRequestor;
}
+
+ abstract Object newReply(ServerChangeStatus status, String leaderId);
+
+ abstract InitialOperationState newInitialOperationState(RaftActorServerConfigurationSupport support);
+
+ abstract void operationComplete(RaftActor raftActor, ServerChangeStatus serverChangeStatus);
+
+ abstract String getServerId();
+ }
+
+ /**
+ * Stores context information for an AddServer operation.
+ */
+ private static class AddServerContext extends ServerOperationContext<AddServer> {
+ AddServerContext(AddServer addServer, ActorRef clientRequestor) {
+ super(addServer, clientRequestor);
+ }
+
+ @Override
+ Object newReply(ServerChangeStatus status, String leaderId) {
+ return new AddServerReply(status, leaderId);
+ }
+
+ @Override
+ InitialOperationState newInitialOperationState(RaftActorServerConfigurationSupport support) {
+ return support.new InitialAddServerState(this);
+ }
+
+ @Override
+ void operationComplete(RaftActor raftActor, ServerChangeStatus serverChangeStatus) {
+
+ }
+
+ @Override
+ String getServerId() {
+ return getOperation().getNewServerId();
+ }
+ }
+
+ private abstract class RemoveServerState extends AbstractOperationState {
+ private final RemoveServerContext removeServerContext;
+
+
+ protected RemoveServerState(RemoveServerContext removeServerContext) {
+ this.removeServerContext = Preconditions.checkNotNull(removeServerContext);
+
+ }
+
+ public RemoveServerContext getRemoveServerContext() {
+ return removeServerContext;
+ }
+ }
+
+ private class InitialRemoveServerState extends RemoveServerState implements InitialOperationState{
+
+ protected InitialRemoveServerState(RemoveServerContext removeServerContext) {
+ super(removeServerContext);
+ }
+
+ @Override
+ public void initiate() {
+ raftContext.removePeer(getRemoveServerContext().getOperation().getServerId());
+ persistNewServerConfiguration(getRemoveServerContext());
+ }
+ }
+
+ private static class RemoveServerContext extends ServerOperationContext<RemoveServer> {
+ private final String peerAddress;
+
+ RemoveServerContext(RemoveServer operation, String peerAddress, ActorRef clientRequestor) {
+ super(operation, clientRequestor);
+ this.peerAddress = peerAddress;
+ }
+
+ @Override
+ Object newReply(ServerChangeStatus status, String leaderId) {
+ return new RemoveServerReply(status, leaderId);
+ }
+
+ @Override
+ InitialOperationState newInitialOperationState(RaftActorServerConfigurationSupport support) {
+ return support.new InitialRemoveServerState(this);
+ }
+
+ @Override
+ void operationComplete(RaftActor raftActor, ServerChangeStatus serverChangeStatus) {
+ if(peerAddress != null) {
+ raftActor.context().actorSelection(peerAddress).tell(new ServerRemoved(getOperation().getServerId()), raftActor.getSelf());
+ }
+ }
+
+ @Override
+ String getServerId() {
+ return getOperation().getServerId();
+ }
+ }
+
+ static class ServerOperationTimeout {
+ private final String serverId;
+
+ ServerOperationTimeout(String serverId){
+ this.serverId = Preconditions.checkNotNull(serverId, "serverId should not be null");
+ }
+
+ String getServerId() {
+ return serverId;
+ }
}
}
Code Review / controller.git / blobdiff