BUG-5626: do not allow overriding of RaftActor.handleCommand()
[controller.git] / opendaylight / md-sal / sal-akka-raft / src / main / java / org / opendaylight / controller / cluster / raft / behaviors / Follower.java
index 3b1e69d0ac5c3270c0bdf761b653c974efe9de7e..7e6654d5d6b9849b106a36bf56c76928798d912d 100644 (file)
@@ -9,7 +9,9 @@
 package org.opendaylight.controller.cluster.raft.behaviors;
 
 import akka.actor.ActorRef;
+import akka.japi.Procedure;
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
 import java.util.ArrayList;
 import org.opendaylight.controller.cluster.raft.RaftActorContext;
 import org.opendaylight.controller.cluster.raft.RaftState;
@@ -37,26 +39,59 @@ import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
  * </ul>
  */
 public class Follower extends AbstractRaftActorBehavior {
-
-    private SnapshotTracker snapshotTracker = null;
+    private static final int SYNC_THRESHOLD = 10;
 
     private final SyncStatusTracker initialSyncStatusTracker;
 
-    private static final int SYNC_THRESHOLD = 10;
+    private final Procedure<ReplicatedLogEntry> appendAndPersistCallback = new Procedure<ReplicatedLogEntry>() {
+        @Override
+        public void apply(ReplicatedLogEntry logEntry) {
+            context.getReplicatedLog().captureSnapshotIfReady(logEntry);
+        }
+    };
+
+    private SnapshotTracker snapshotTracker = null;
+    private String leaderId;
+    private short leaderPayloadVersion;
 
     public Follower(RaftActorContext context) {
+        this(context, null, (short)-1);
+    }
+
+    public Follower(RaftActorContext context, String initialLeaderId, short initialLeaderPayloadVersion) {
         super(context, RaftState.Follower);
+        this.leaderId = initialLeaderId;
+        this.leaderPayloadVersion = initialLeaderPayloadVersion;
 
         initialSyncStatusTracker = new SyncStatusTracker(context.getActor(), getId(), SYNC_THRESHOLD);
 
-        if(context.getRaftPolicy().automaticElectionsEnabled()) {
-            if (context.getPeerIds().isEmpty()) {
-                actor().tell(ELECTION_TIMEOUT, actor());
+        if(canStartElection()) {
+            if (context.getPeerIds().isEmpty() && getLeaderId() == null) {
+                actor().tell(ElectionTimeout.INSTANCE, actor());
             } else {
                 scheduleElection(electionDuration());
             }
         }
+    }
+
+    @Override
+    public final String getLeaderId() {
+        return leaderId;
+    }
+
+    @VisibleForTesting
+    protected final void setLeaderId(final String leaderId) {
+        this.leaderId = Preconditions.checkNotNull(leaderId);
+    }
+
+    @Override
+    public short getLeaderPayloadVersion() {
+        return leaderPayloadVersion;
+    }
 
+    @VisibleForTesting
+    protected final void setLeaderPayloadVersion(short leaderPayloadVersion) {
+        this.leaderPayloadVersion = leaderPayloadVersion;
     }
 
     private boolean isLogEntryPresent(long index){
@@ -90,8 +125,8 @@ public class Follower extends AbstractRaftActorBehavior {
         initialSyncStatusTracker.update(leaderId, currentLeaderCommit, context.getCommitIndex());
     }
 
-    @Override protected RaftActorBehavior handleAppendEntries(ActorRef sender,
-                                                              AppendEntries appendEntries) {
+    @Override
+    protected RaftActorBehavior handleAppendEntries(ActorRef sender, AppendEntries appendEntries) {
 
         int numLogEntries = appendEntries.getEntries() != null ? appendEntries.getEntries().size() : 0;
         if(LOG.isTraceEnabled()) {
@@ -119,8 +154,7 @@ public class Follower extends AbstractRaftActorBehavior {
 
         // If we got here then we do appear to be talking to the leader
         leaderId = appendEntries.getLeaderId();
-
-        setLeaderPayloadVersion(appendEntries.getPayloadVersion());
+        leaderPayloadVersion = appendEntries.getPayloadVersion();
 
         updateInitialSyncStatus(appendEntries.getLeaderCommit(), appendEntries.getLeaderId());
         // First check if the logs are in sync or not
@@ -189,7 +223,7 @@ public class Follower extends AbstractRaftActorBehavior {
 
                 LOG.debug("{}: Append entry to log {}", logName(), entry.getData());
 
-                context.getReplicatedLog().appendAndPersist(entry);
+                context.getReplicatedLog().appendAndPersist(entry, appendAndPersistCallback);
 
                 if(entry.getData() instanceof ServerConfigurationPayload) {
                     context.updatePeerIds((ServerConfigurationPayload)entry.getData());
@@ -278,7 +312,8 @@ public class Follower extends AbstractRaftActorBehavior {
                     logName(), prevLogTerm, appendEntries.getPrevLogTerm());
         } else if(appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
                 && appendEntries.getReplicatedToAllIndex() != -1
-                && !isLogEntryPresent(appendEntries.getReplicatedToAllIndex())) {
+                && !isLogEntryPresent(appendEntries.getReplicatedToAllIndex())
+                && !context.getReplicatedLog().isInSnapshot(appendEntries.getReplicatedToAllIndex())) {
             // This append entry comes from a leader who has it's log aggressively trimmed and so does not have
             // the previous entry in it's in-memory journal
 
@@ -286,8 +321,9 @@ public class Follower extends AbstractRaftActorBehavior {
                     "{}: Cannot append entries because the replicatedToAllIndex {} does not appear to be in the in-memory journal",
                     logName(), appendEntries.getReplicatedToAllIndex());
         } else if(appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
-                && appendEntries.getReplicatedToAllIndex() != -1 && numLogEntries > 0 &&
-                !isLogEntryPresent(appendEntries.getEntries().get(0).getIndex() - 1)){
+                && appendEntries.getReplicatedToAllIndex() != -1 && numLogEntries > 0
+                && !isLogEntryPresent(appendEntries.getEntries().get(0).getIndex() - 1)
+                && !context.getReplicatedLog().isInSnapshot(appendEntries.getEntries().get(0).getIndex() - 1)) {
             LOG.debug(
                     "{}: Cannot append entries because the calculated previousIndex {} was not found in the in-memory journal",
                     logName(), appendEntries.getEntries().get(0).getIndex() - 1);
@@ -297,54 +333,65 @@ public class Follower extends AbstractRaftActorBehavior {
         return outOfSync;
     }
 
-    @Override protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
+    @Override
+    protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
         AppendEntriesReply appendEntriesReply) {
         return this;
     }
 
-    @Override protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
+    @Override
+    protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
         RequestVoteReply requestVoteReply) {
         return this;
     }
 
-    @Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
+    @Override
+    public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
+        if (originalMessage instanceof ElectionTimeout) {
+            if (canStartElection()) {
+                LOG.debug("{}: Received ElectionTimeout - switching to Candidate", logName());
+                return internalSwitchBehavior(RaftState.Candidate);
+            } else {
+                return this;
+            }
+        }
 
-        Object message = fromSerializableMessage(originalMessage);
+        final Object message = fromSerializableMessage(originalMessage);
+        if (!(message instanceof RaftRPC)) {
+            // The rest of the processing requires the message to be a RaftRPC
+            return null;
+        }
 
-        if (message instanceof RaftRPC) {
-            RaftRPC rpc = (RaftRPC) message;
-            // If RPC request or response contains term T > currentTerm:
-            // set currentTerm = T, convert to follower (§5.1)
-            // This applies to all RPC messages and responses
-            if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
-                LOG.debug("{}: Term {} in \"{}\" message is greater than follower's term {} - updating term",
-                        logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
+        final RaftRPC rpc = (RaftRPC) message;
+        // If RPC request or response contains term T > currentTerm:
+        // set currentTerm = T, convert to follower (§5.1)
+        // This applies to all RPC messages and responses
+        if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
+            LOG.debug("{}: Term {} in \"{}\" message is greater than follower's term {} - updating term",
+                logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
 
-                context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
-            }
+            context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
         }
 
-        if (message instanceof ElectionTimeout) {
-            LOG.debug("{}: Received ElectionTimeout - switching to Candidate", logName());
-            return internalSwitchBehavior(RaftState.Candidate);
-
-        } else if (message instanceof InstallSnapshot) {
-            InstallSnapshot installSnapshot = (InstallSnapshot) message;
+        if (rpc instanceof InstallSnapshot) {
+            InstallSnapshot installSnapshot = (InstallSnapshot) rpc;
             handleInstallSnapshot(sender, installSnapshot);
+            scheduleElection(electionDuration());
+            return this;
         }
 
-        if(message instanceof RaftRPC && (!(message instanceof RequestVote) || (canGrantVote((RequestVote) message)))){
+        if (!(rpc instanceof RequestVote) || canGrantVote((RequestVote) rpc)) {
             scheduleElection(electionDuration());
         }
 
-        return super.handleMessage(sender, message);
+        return super.handleMessage(sender, rpc);
     }
 
     private void handleInstallSnapshot(final ActorRef sender, InstallSnapshot installSnapshot) {
 
-        LOG.debug("{}: InstallSnapshot received from leader {}, datasize: {} , Chunk: {}/{}",
-                    logName(), installSnapshot.getLeaderId(), installSnapshot.getData().size(),
-                    installSnapshot.getChunkIndex(), installSnapshot.getTotalChunks());
+        LOG.debug("{}: handleInstallSnapshot: {}", logName(), installSnapshot);
+
+        leaderId = installSnapshot.getLeaderId();
 
         if(snapshotTracker == null){
             snapshotTracker = new SnapshotTracker(LOG, installSnapshot.getTotalChunks());
@@ -366,7 +413,7 @@ public class Follower extends AbstractRaftActorBehavior {
                         installSnapshot.getLastIncludedTerm(),
                         context.getTermInformation().getCurrentTerm(),
                         context.getTermInformation().getVotedFor(),
-                        context.getPeerServerInfo());
+                        context.getPeerServerInfo(true));
 
                 ApplySnapshot.Callback applySnapshotCallback = new ApplySnapshot.Callback() {
                     @Override
@@ -408,7 +455,7 @@ public class Follower extends AbstractRaftActorBehavior {
     }
 
     @Override
-    public void close() throws Exception {
+    public void close() {
         stopElection();
     }