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 / AbstractLeader.java
index 578989599752f41c0fefd635c879effbc187c357..d914154f8bb5565c64836f7f97282a7390aa37e4 100644 (file)
@@ -14,10 +14,9 @@ import akka.actor.Cancellable;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableMap.Builder;
 import com.google.protobuf.ByteString;
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -31,10 +30,12 @@ import org.opendaylight.controller.cluster.raft.ClientRequestTracker;
 import org.opendaylight.controller.cluster.raft.ClientRequestTrackerImpl;
 import org.opendaylight.controller.cluster.raft.FollowerLogInformation;
 import org.opendaylight.controller.cluster.raft.FollowerLogInformationImpl;
+import org.opendaylight.controller.cluster.raft.PeerInfo;
 import org.opendaylight.controller.cluster.raft.RaftActorContext;
 import org.opendaylight.controller.cluster.raft.RaftState;
 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
 import org.opendaylight.controller.cluster.raft.Snapshot;
+import org.opendaylight.controller.cluster.raft.VotingState;
 import org.opendaylight.controller.cluster.raft.base.messages.Replicate;
 import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat;
 import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot;
@@ -44,6 +45,7 @@ import org.opendaylight.controller.cluster.raft.messages.InstallSnapshot;
 import org.opendaylight.controller.cluster.raft.messages.InstallSnapshotReply;
 import org.opendaylight.controller.cluster.raft.messages.RaftRPC;
 import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
+import org.opendaylight.controller.cluster.raft.messages.UnInitializedFollowerSnapshotReply;
 import scala.concurrent.duration.FiniteDuration;
 
 /**
@@ -79,46 +81,28 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
     // This would be passed as the hash code of the last chunk when sending the first chunk
     public static final int INITIAL_LAST_CHUNK_HASH_CODE = -1;
 
-    private final Map<String, FollowerLogInformation> followerToLog;
+    private final Map<String, FollowerLogInformation> followerToLog = new HashMap<>();
     private final Map<String, FollowerToSnapshot> mapFollowerToSnapshot = new HashMap<>();
 
     private Cancellable heartbeatSchedule = null;
 
     private final Collection<ClientRequestTracker> trackerList = new LinkedList<>();
 
-    protected final int minReplicationCount;
-
-    protected final int minIsolatedLeaderPeerCount;
+    private int minReplicationCount;
 
     private Optional<SnapshotHolder> snapshot;
 
-    public AbstractLeader(RaftActorContext context) {
-        super(context, RaftState.Leader);
-
-        setLeaderPayloadVersion(context.getPayloadVersion());
-
-        final Builder<String, FollowerLogInformation> ftlBuilder = ImmutableMap.builder();
-        for (String followerId : context.getPeerAddresses().keySet()) {
-            FollowerLogInformation followerLogInformation =
-                new FollowerLogInformationImpl(followerId, -1, context);
+    protected AbstractLeader(RaftActorContext context, RaftState state) {
+        super(context, state);
 
-            ftlBuilder.put(followerId, followerLogInformation);
+        for(PeerInfo peerInfo: context.getPeers()) {
+            FollowerLogInformation followerLogInformation = new FollowerLogInformationImpl(peerInfo, -1, context);
+            followerToLog.put(peerInfo.getId(), followerLogInformation);
         }
-        followerToLog = ftlBuilder.build();
-
-        leaderId = context.getId();
 
         LOG.debug("{}: Election: Leader has following peers: {}", logName(), getFollowerIds());
 
-        minReplicationCount = getMajorityVoteCount(getFollowerIds().size());
-
-        // the isolated Leader peer count will be 1 less than the majority vote count.
-        // this is because the vote count has the self vote counted in it
-        // for e.g
-        // 0 peers = 1 votesRequired , minIsolatedLeaderPeerCount = 0
-        // 2 peers = 2 votesRequired , minIsolatedLeaderPeerCount = 1
-        // 4 peers = 3 votesRequired, minIsolatedLeaderPeerCount = 2
-        minIsolatedLeaderPeerCount = minReplicationCount > 0 ? (minReplicationCount - 1) : 0;
+        updateMinReplicaCount();
 
         snapshot = Optional.absent();
 
@@ -141,6 +125,43 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
         return followerToLog.keySet();
     }
 
+    public void addFollower(String followerId) {
+        FollowerLogInformation followerLogInformation = new FollowerLogInformationImpl(
+                context.getPeerInfo(followerId), -1, context);
+        followerToLog.put(followerId, followerLogInformation);
+
+        if(heartbeatSchedule == null) {
+            scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval());
+        }
+    }
+
+    public void removeFollower(String followerId) {
+        followerToLog.remove(followerId);
+        mapFollowerToSnapshot.remove(followerId);
+    }
+
+    public void updateMinReplicaCount() {
+        int numVoting = 0;
+        for(PeerInfo peer: context.getPeers()) {
+            if(peer.isVoting()) {
+                numVoting++;
+            }
+        }
+
+        minReplicationCount = getMajorityVoteCount(numVoting);
+    }
+
+    protected int getMinIsolatedLeaderPeerCount(){
+      //the isolated Leader peer count will be 1 less than the majority vote count.
+        //this is because the vote count has the self vote counted in it
+        //for e.g
+        //0 peers = 1 votesRequired , minIsolatedLeaderPeerCount = 0
+        //2 peers = 2 votesRequired , minIsolatedLeaderPeerCount = 1
+        //4 peers = 3 votesRequired, minIsolatedLeaderPeerCount = 2
+
+        return minReplicationCount > 0 ? (minReplicationCount - 1) : 0;
+    }
+
     @VisibleForTesting
     void setSnapshot(@Nullable Snapshot snapshot) {
         if(snapshot != null) {
@@ -187,6 +208,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
 
         followerLogInformation.markFollowerActive();
         followerLogInformation.setPayloadVersion(appendEntriesReply.getPayloadVersion());
+        followerLogInformation.setRaftVersion(appendEntriesReply.getRaftVersion());
 
         boolean updated = false;
         if (appendEntriesReply.isSuccess()) {
@@ -231,15 +253,24 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
             int replicatedCount = 1;
 
             for (FollowerLogInformation info : followerToLog.values()) {
-                if (info.getMatchIndex() >= N) {
+                final PeerInfo peerInfo = context.getPeerInfo(info.getId());
+                if(info.getMatchIndex() >= N && (peerInfo != null && peerInfo.isVoting())) {
                     replicatedCount++;
                 }
             }
 
             if (replicatedCount >= minReplicationCount) {
                 ReplicatedLogEntry replicatedLogEntry = context.getReplicatedLog().get(N);
-                if (replicatedLogEntry != null &&
-                    replicatedLogEntry.getTerm() == currentTerm()) {
+                if (replicatedLogEntry == null) {
+                    break;
+                }
+
+                // Don't update the commit index if the log entry is from a previous term, as per §5.4.1:
+                // "Raft never commits log entries from previous terms by counting replicas".
+                // However we keep looping so we can make progress when new entries in the current term
+                // reach consensus, as per §5.4.1: "once an entry from the current term is committed by
+                // counting replicas, then all prior entries are committed indirectly".
+                if (replicatedLogEntry.getTerm() == currentTerm()) {
                     context.setCommitIndex(N);
                 }
             } else {
@@ -349,23 +380,19 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
             beforeSendHeartbeat();
             sendHeartBeat();
             scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval());
-            return this;
-
         } else if(message instanceof SendInstallSnapshot) {
             // received from RaftActor
             setSnapshot(((SendInstallSnapshot) message).getSnapshot());
             sendInstallSnapshot();
-
         } else if (message instanceof Replicate) {
             replicate((Replicate) message);
-
-        } else if (message instanceof InstallSnapshotReply){
+        } else if (message instanceof InstallSnapshotReply) {
             handleInstallSnapshotReply((InstallSnapshotReply) message);
-
+        } else {
+            return super.handleMessage(sender, message);
         }
 
-
-        return super.handleMessage(sender, message);
+        return this;
     }
 
     private void handleInstallSnapshotReply(InstallSnapshotReply reply) {
@@ -375,12 +402,20 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
         FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId);
 
         if (followerToSnapshot == null) {
-            LOG.error("{}: FollowerId {} in InstallSnapshotReply not known to Leader",
+            LOG.error("{}: FollowerToSnapshot not found for follower {} in InstallSnapshotReply",
                     logName(), followerId);
             return;
         }
 
         FollowerLogInformation followerLogInformation = followerToLog.get(followerId);
+        if(followerLogInformation == null) {
+            // This can happen during AddServer if it times out.
+            LOG.error("{}: FollowerLogInformation not found for follower {} in InstallSnapshotReply",
+                    logName(), followerId);
+            mapFollowerToSnapshot.remove(followerId);
+            return;
+        }
+
         followerLogInformation.markFollowerActive();
 
         if (followerToSnapshot.getChunkIndex() == reply.getChunkIndex()) {
@@ -402,8 +437,8 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
                     mapFollowerToSnapshot.remove(followerId);
 
                     LOG.debug("{}: follower: {}, matchIndex set to {}, nextIndex set to {}",
-                                logName(), followerId, followerLogInformation.getMatchIndex(),
-                                followerLogInformation.getNextIndex());
+                        logName(), followerId, followerLogInformation.getMatchIndex(),
+                        followerLogInformation.getNextIndex());
 
                     if (mapFollowerToSnapshot.isEmpty()) {
                         // once there are no pending followers receiving snapshots
@@ -411,7 +446,12 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
                         setSnapshot(null);
                     }
                     wasLastChunk = true;
-
+                    if(context.getPeerInfo(followerId).getVotingState() == VotingState.VOTING_NOT_INITIALIZED){
+                        UnInitializedFollowerSnapshotReply unInitFollowerSnapshotSuccess =
+                                             new UnInitializedFollowerSnapshotReply(followerId);
+                        context.getActor().tell(unInitFollowerSnapshotSuccess, context.getActor());
+                        LOG.debug("Sent message UnInitializedFollowerSnapshotReply to self");
+                    }
                 } else {
                     followerToSnapshot.markSendStatus(true);
                 }
@@ -472,7 +512,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
         }
     }
 
-    private void sendAppendEntries(long timeSinceLastActivityInterval, boolean isHeartbeat) {
+    protected void sendAppendEntries(long timeSinceLastActivityInterval, boolean isHeartbeat) {
         // Send an AppendEntries to all followers
         for (Entry<String, FollowerLogInformation> e : followerToLog.entrySet()) {
             final String followerId = e.getKey();
@@ -578,7 +618,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
                     appendEntries);
         }
 
-        followerActor.tell(appendEntries.toSerializable(), actor());
+        followerActor.tell(appendEntries, actor());
     }
 
     /**
@@ -594,17 +634,16 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
      * then send the existing snapshot in chunks to the follower.
      * @param followerId
      */
-    private void initiateCaptureSnapshot(String followerId) {
+    public boolean initiateCaptureSnapshot(String followerId) {
         if (snapshot.isPresent()) {
             // if a snapshot is present in the memory, most likely another install is in progress
             // no need to capture snapshot.
             // This could happen if another follower needs an install when one is going on.
             final ActorSelection followerActor = context.getPeerActorSelection(followerId);
             sendSnapshotChunk(followerActor, followerId);
-
-
+            return true;
         } else {
-            context.getSnapshotManager().captureToInstall(context.getReplicatedLog().last(),
+            return context.getSnapshotManager().captureToInstall(context.getReplicatedLog().last(),
                     this.getReplicatedToAllIndex(), followerId);
         }
     }
@@ -623,12 +662,15 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
     private void sendInstallSnapshot() {
         LOG.debug("{}: sendInstallSnapshot", logName());
         for (Entry<String, FollowerLogInformation> e : followerToLog.entrySet()) {
-            ActorSelection followerActor = context.getPeerActorSelection(e.getKey());
+            String followerId = e.getKey();
+            ActorSelection followerActor = context.getPeerActorSelection(followerId);
+            FollowerLogInformation followerLogInfo = e.getValue();
 
             if (followerActor != null) {
-                long nextIndex = e.getValue().getNextIndex();
-                if (canInstallSnapshot(nextIndex)) {
-                    sendSnapshotChunk(followerActor, e.getKey());
+                long nextIndex = followerLogInfo.getNextIndex();
+                if (context.getPeerInfo(followerId).getVotingState() == VotingState.VOTING_NOT_INITIALIZED ||
+                        canInstallSnapshot(nextIndex)) {
+                    sendSnapshotChunk(followerActor, followerId);
                 }
             }
         }
@@ -641,7 +683,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
     private void sendSnapshotChunk(ActorSelection followerActor, String followerId) {
         try {
             if (snapshot.isPresent()) {
-                ByteString nextSnapshotChunk = getNextSnapshotChunk(followerId, snapshot.get().getSnapshotBytes());
+                byte[] nextSnapshotChunk = getNextSnapshotChunk(followerId, snapshot.get().getSnapshotBytes());
 
                 // Note: the previous call to getNextSnapshotChunk has the side-effect of adding
                 // followerId to the followerToSnapshot map.
@@ -655,7 +697,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
                         followerToSnapshot.incrementChunkIndex(),
                         followerToSnapshot.getTotalChunks(),
                         Optional.of(followerToSnapshot.getLastChunkHashCode())
-                    ).toSerializable(),
+                    ).toSerializable(followerToLog.get(followerId).getRaftVersion()),
                     actor()
                 );
 
@@ -674,15 +716,15 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
      * Acccepts snaphot as ByteString, enters into map for future chunks
      * creates and return a ByteString chunk
      */
-    private ByteString getNextSnapshotChunk(String followerId, ByteString snapshotBytes) throws IOException {
+    private byte[] getNextSnapshotChunk(String followerId, ByteString snapshotBytes) throws IOException {
         FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId);
         if (followerToSnapshot == null) {
             followerToSnapshot = new FollowerToSnapshot(snapshotBytes);
             mapFollowerToSnapshot.put(followerId, followerToSnapshot);
         }
-        ByteString nextChunk = followerToSnapshot.getNextChunk();
+        byte[] nextChunk = followerToSnapshot.getNextChunk();
 
-        LOG.debug("{}: next snapshot chunk size for follower {}: {}", logName(), followerId, nextChunk.size());
+        LOG.debug("{}: next snapshot chunk size for follower {}: {}", logName(), followerId, nextChunk.length);
 
         return nextChunk;
     }
@@ -715,22 +757,27 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
         // need to be sent if there are other messages being sent to the remote
         // actor.
         heartbeatSchedule = context.getActorSystem().scheduler().scheduleOnce(
-            interval, context.getActor(), new SendHeartBeat(),
+            interval, context.getActor(), SendHeartBeat.INSTANCE,
             context.getActorSystem().dispatcher(), context.getActor());
     }
 
     @Override
-    public void close() throws Exception {
+    public void close() {
         stopHeartBeat();
     }
 
     @Override
-    public String getLeaderId() {
+    public final String getLeaderId() {
         return context.getId();
     }
 
+    @Override
+    public final short getLeaderPayloadVersion() {
+        return context.getPayloadVersion();
+    }
+
     protected boolean isLeaderIsolated() {
-        int minPresent = minIsolatedLeaderPeerCount;
+        int minPresent = getMinIsolatedLeaderPeerCount();
         for (FollowerLogInformation followerLogInformation : followerToLog.values()) {
             if (followerLogInformation.isFollowerActive()) {
                 --minPresent;
@@ -821,25 +868,23 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
             }
         }
 
-        public ByteString getNextChunk() {
+        public byte[] getNextChunk() {
             int snapshotLength = getSnapshotBytes().size();
             int start = incrementOffset();
             int size = context.getConfigParams().getSnapshotChunkSize();
             if (context.getConfigParams().getSnapshotChunkSize() > snapshotLength) {
                 size = snapshotLength;
-            } else {
-                if ((start + context.getConfigParams().getSnapshotChunkSize()) > snapshotLength) {
-                    size = snapshotLength - start;
-                }
+            } else if ((start + context.getConfigParams().getSnapshotChunkSize()) > snapshotLength) {
+                size = snapshotLength - start;
             }
 
+            byte[] nextChunk = new byte[size];
+            getSnapshotBytes().copyTo(nextChunk, start, 0, size);
+            nextChunkHashCode = Arrays.hashCode(nextChunk);
 
-            LOG.debug("{}: Next chunk: length={}, offset={},size={}", logName(),
-                    snapshotLength, start, size);
-
-            ByteString substring = getSnapshotBytes().substring(start, start + size);
-            nextChunkHashCode = substring.hashCode();
-            return substring;
+            LOG.debug("{}: Next chunk: total length={}, offset={}, size={}, hashCode={}", logName(),
+                    snapshotLength, start, size, nextChunkHashCode);
+            return nextChunk;
         }
 
         /**