Merge "BUG 2509 : Removing all journal entries from a Followers in-memory journal...
[controller.git] / opendaylight / md-sal / sal-akka-raft / src / main / java / org / opendaylight / controller / cluster / raft / behaviors / Follower.java
index 7ada8b31c54f75c9c8f8dc9ce3456260d77af80a..cc2e55d51b115cc124890c3e643ed810244a7c24 100644 (file)
@@ -9,7 +9,9 @@
 package org.opendaylight.controller.cluster.raft.behaviors;
 
 import akka.actor.ActorRef;
+import com.google.common.annotations.VisibleForTesting;
 import com.google.protobuf.ByteString;
+import java.util.ArrayList;
 import org.opendaylight.controller.cluster.raft.RaftActorContext;
 import org.opendaylight.controller.cluster.raft.RaftState;
 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
@@ -23,8 +25,6 @@ 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 java.util.ArrayList;
-
 /**
  * The behavior of a RaftActor in the Follower state
  * <p/>
@@ -36,7 +36,8 @@ import java.util.ArrayList;
  * </ul>
  */
 public class Follower extends AbstractRaftActorBehavior {
-    private ByteString snapshotChunksCollected = ByteString.EMPTY;
+
+    private SnapshotTracker snapshotTracker = null;
 
     public Follower(RaftActorContext context) {
         super(context);
@@ -44,8 +45,35 @@ public class Follower extends AbstractRaftActorBehavior {
         scheduleElection(electionDuration());
     }
 
+    private boolean isLogEntryPresent(long index){
+        if(index == context.getReplicatedLog().getSnapshotIndex()){
+            return true;
+        }
+
+        ReplicatedLogEntry previousEntry = context.getReplicatedLog()
+                .get(index);
+
+        return previousEntry != null;
+
+    }
+
+    private long getLogEntryTerm(long index){
+        if(index == context.getReplicatedLog().getSnapshotIndex()){
+            return context.getReplicatedLog().getSnapshotTerm();
+        }
+
+        ReplicatedLogEntry previousEntry = context.getReplicatedLog()
+                .get(index);
+
+        if(previousEntry != null){
+            return previousEntry.getTerm();
+        }
+
+        return -1;
+    }
+
     @Override protected RaftActorBehavior handleAppendEntries(ActorRef sender,
-        AppendEntries appendEntries) {
+                                                              AppendEntries appendEntries) {
 
         if(appendEntries.getEntries() != null && appendEntries.getEntries().size() > 0) {
             if(LOG.isDebugEnabled()) {
@@ -66,15 +94,15 @@ public class Follower extends AbstractRaftActorBehavior {
         // 2. Reply false if log doesn’t contain an entry at prevLogIndex
         // whose term matches prevLogTerm (§5.3)
 
-        ReplicatedLogEntry previousEntry = context.getReplicatedLog()
-            .get(appendEntries.getPrevLogIndex());
+        long prevLogTerm = getLogEntryTerm(appendEntries.getPrevLogIndex());
+        boolean prevEntryPresent = isLogEntryPresent(appendEntries.getPrevLogIndex());
 
 
         boolean outOfSync = true;
 
         // First check if the logs are in sync or not
         if (lastIndex() == -1
-            && appendEntries.getPrevLogIndex() != -1) {
+                && appendEntries.getPrevLogIndex() != -1) {
 
             // The follower's log is out of sync because the leader does have
             // an entry at prevLogIndex and this follower has no entries in
@@ -82,34 +110,34 @@ public class Follower extends AbstractRaftActorBehavior {
 
             if(LOG.isDebugEnabled()) {
                 LOG.debug("The followers log is empty and the senders prevLogIndex is {}",
-                    appendEntries.getPrevLogIndex());
+                        appendEntries.getPrevLogIndex());
             }
 
         } else if (lastIndex() > -1
-            && appendEntries.getPrevLogIndex() != -1
-            && previousEntry == null) {
+                && appendEntries.getPrevLogIndex() != -1
+                && !prevEntryPresent) {
 
             // The follower's log is out of sync because the Leader's
             // prevLogIndex entry was not found in it's log
 
             if(LOG.isDebugEnabled()) {
                 LOG.debug("The log is not empty but the prevLogIndex {} was not found in it",
-                    appendEntries.getPrevLogIndex());
+                        appendEntries.getPrevLogIndex());
             }
 
         } else if (lastIndex() > -1
-            && previousEntry != null
-            && previousEntry.getTerm()!= appendEntries.getPrevLogTerm()) {
+                && prevEntryPresent
+                && prevLogTerm != appendEntries.getPrevLogTerm()) {
 
             // The follower's log is out of sync because the Leader's
             // prevLogIndex entry does exist in the follower's log but it has
             // a different term in it
 
-            if(LOG.isDebugEnabled()) {
+            if (LOG.isDebugEnabled()) {
                 LOG.debug(
-                    "Cannot append entries because previous entry term {}  is not equal to append entries prevLogTerm {}"
-                    , previousEntry.getTerm()
-                    , appendEntries.getPrevLogTerm());
+                        "Cannot append entries because previous entry term {}  is not equal to append entries prevLogTerm {}"
+                        , prevLogTerm
+                        , appendEntries.getPrevLogTerm());
             }
         } else {
             outOfSync = false;
@@ -119,9 +147,9 @@ public class Follower extends AbstractRaftActorBehavior {
             // We found that the log was out of sync so just send a negative
             // reply and return
             if(LOG.isDebugEnabled()) {
-                LOG.debug("Follower is out-of-sync, " +
+                LOG.debug("Follower ({}) is out-of-sync, " +
                         "so sending negative reply, lastIndex():{}, lastTerm():{}",
-                    lastIndex(), lastTerm()
+                        context.getId(), lastIndex(), lastTerm()
                 );
             }
             sender.tell(
@@ -280,48 +308,54 @@ public class Follower extends AbstractRaftActorBehavior {
             );
         }
 
-        try {
-            if (installSnapshot.getChunkIndex() == installSnapshot.getTotalChunks()) {
-                // this is the last chunk, create a snapshot object and apply
-
-                snapshotChunksCollected = snapshotChunksCollected.concat(installSnapshot.getData());
-                if(LOG.isDebugEnabled()) {
-                    LOG.debug("Last chunk received: snapshotChunksCollected.size:{}",
-                            snapshotChunksCollected.size());
-                }
+        if(snapshotTracker == null){
+            snapshotTracker = new SnapshotTracker(LOG, installSnapshot.getTotalChunks());
+        }
 
-                Snapshot snapshot = Snapshot.create(snapshotChunksCollected.toByteArray(),
-                    new ArrayList<ReplicatedLogEntry>(),
-                    installSnapshot.getLastIncludedIndex(),
-                    installSnapshot.getLastIncludedTerm(),
-                    installSnapshot.getLastIncludedIndex(),
-                    installSnapshot.getLastIncludedTerm());
+        try {
+            if(snapshotTracker.addChunk(installSnapshot.getChunkIndex(), installSnapshot.getData(),
+                    installSnapshot.getLastChunkHashCode())){
+                Snapshot snapshot = Snapshot.create(snapshotTracker.getSnapshot(),
+                        new ArrayList<ReplicatedLogEntry>(),
+                        installSnapshot.getLastIncludedIndex(),
+                        installSnapshot.getLastIncludedTerm(),
+                        installSnapshot.getLastIncludedIndex(),
+                        installSnapshot.getLastIncludedTerm());
 
                 actor().tell(new ApplySnapshot(snapshot), actor());
 
-            } else {
-                // we have more to go
-                snapshotChunksCollected = snapshotChunksCollected.concat(installSnapshot.getData());
+                snapshotTracker = null;
 
-                if(LOG.isDebugEnabled()) {
-                    LOG.debug("Chunk={},snapshotChunksCollected.size:{}",
-                        installSnapshot.getChunkIndex(), snapshotChunksCollected.size());
-                }
             }
 
             sender.tell(new InstallSnapshotReply(
-                currentTerm(), context.getId(), installSnapshot.getChunkIndex(),
-                true), actor());
+                    currentTerm(), context.getId(), installSnapshot.getChunkIndex(),
+                    true), actor());
+
+        } catch (SnapshotTracker.InvalidChunkException e) {
+
+            sender.tell(new InstallSnapshotReply(currentTerm(), context.getId(),
+                    -1, false), actor());
+            snapshotTracker = null;
+
+        } catch (Exception e){
 
-        } catch (Exception e) {
             LOG.error(e, "Exception in InstallSnapshot of follower:");
             //send reply with success as false. The chunk will be sent again on failure
             sender.tell(new InstallSnapshotReply(currentTerm(), context.getId(),
-                installSnapshot.getChunkIndex(), false), actor());
+                    installSnapshot.getChunkIndex(), false), actor());
+
         }
     }
 
     @Override public void close() throws Exception {
         stopElection();
     }
+
+    @VisibleForTesting
+    ByteString getSnapshotChunksCollected(){
+        return snapshotTracker != null ? snapshotTracker.getCollectedChunks() : ByteString.EMPTY;
+    }
+
+
 }