X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-akka-raft%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fraft%2Fbehaviors%2FLeader.java;h=3534ac5cf142eda058ceb1e39b90d311b096b20b;hp=36e9b646e66f069504e8d220ceafb80bdc0a1b6a;hb=refs%2Fchanges%2F09%2F83009%2F6;hpb=f276ae33b951d173b51c467bb7bb1a5f5cf9a1e6

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java
index 36e9b646e6..3534ac5cf1 100644
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java
@@ -7,24 +7,27 @@
  */
 package org.opendaylight.controller.cluster.raft.behaviors;
 
+import static java.util.Objects.requireNonNull;
+
 import akka.actor.ActorRef;
 import akka.actor.ActorSelection;
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Preconditions;
 import com.google.common.base.Stopwatch;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
 import org.opendaylight.controller.cluster.raft.FollowerLogInformation;
 import org.opendaylight.controller.cluster.raft.RaftActorContext;
 import org.opendaylight.controller.cluster.raft.RaftActorLeadershipTransferCohort;
 import org.opendaylight.controller.cluster.raft.RaftState;
-import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
+import org.opendaylight.controller.cluster.raft.base.messages.TimeoutNow;
 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
 
 /**
- * The behavior of a RaftActor when it is in the Leader state
- * <p/>
+ * The behavior of a RaftActor when it is in the Leader state.
+ *
+ * <p>
  * Leaders:
  * <ul>
  * <li> Upon election: send initial empty AppendEntries RPCs
@@ -34,15 +37,14 @@ import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  * respond after entry applied to state machine (§5.3)
  * <li> If last log index ≥ nextIndex for a follower: send
  * AppendEntries RPC with log entries starting at nextIndex
- * <ul>
  * <li> If successful: update nextIndex and matchIndex for
  * follower (§5.3)
  * <li> If AppendEntries fails because of log inconsistency:
  * decrement nextIndex and retry (§5.3)
- * </ul>
- * <li> If there exists an N such that N > commitIndex, a majority
+ * <li> If there exists an N such that N &gt; commitIndex, a majority
  * of matchIndex[i] ≥ N, and log[N].term == currentTerm:
  * set commitIndex = N (§5.3, §5.4).
+ * </ul>
  */
 public class Leader extends AbstractLeader {
     /**
@@ -55,19 +57,23 @@ public class Leader extends AbstractLeader {
     private final Stopwatch isolatedLeaderCheck = Stopwatch.createStarted();
     private @Nullable LeadershipTransferContext leadershipTransferContext;
 
-    public Leader(RaftActorContext context) {
-        super(context, RaftState.Leader);
+    Leader(final RaftActorContext context, @Nullable final AbstractLeader initializeFromLeader) {
+        super(context, RaftState.Leader, initializeFromLeader);
+    }
+
+    public Leader(final RaftActorContext context) {
+        this(context, null);
     }
 
     @Override
-    public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
-        Preconditions.checkNotNull(sender, "sender should not be null");
+    public RaftActorBehavior handleMessage(final ActorRef sender, final Object originalMessage) {
+        requireNonNull(sender, "sender should not be null");
 
         if (ISOLATED_LEADER_CHECK.equals(originalMessage)) {
             if (isLeaderIsolated()) {
-                LOG.warn("{}: At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
+                log.warn("{}: At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
                     context.getId(), getMinIsolatedLeaderPeerCount(), getLeaderId());
-                return internalSwitchBehavior(RaftState.IsolatedLeader);
+                return internalSwitchBehavior(new IsolatedLeader(context, this));
             } else {
                 return this;
             }
@@ -77,21 +83,23 @@ public class Leader extends AbstractLeader {
     }
 
     @Override
-    protected void beforeSendHeartbeat(){
-        if(isolatedLeaderCheck.elapsed(TimeUnit.MILLISECONDS) > context.getConfigParams().getIsolatedCheckIntervalInMillis()){
+    protected void beforeSendHeartbeat() {
+        if (isolatedLeaderCheck.elapsed(TimeUnit.MILLISECONDS)
+                > context.getConfigParams().getIsolatedCheckIntervalInMillis()) {
             context.getActor().tell(ISOLATED_LEADER_CHECK, context.getActor());
             isolatedLeaderCheck.reset().start();
         }
 
-        if(leadershipTransferContext != null && leadershipTransferContext.isExpired(
+        if (leadershipTransferContext != null && leadershipTransferContext.isExpired(
                 context.getConfigParams().getElectionTimeOutInterval().toMillis())) {
-            LOG.debug("{}: Leadership transfer expired", logName());
+            log.debug("{}: Leadership transfer expired", logName());
             leadershipTransferContext = null;
         }
     }
 
     @Override
-    protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender, AppendEntriesReply appendEntriesReply) {
+    protected RaftActorBehavior handleAppendEntriesReply(final ActorRef sender,
+            final AppendEntriesReply appendEntriesReply) {
         RaftActorBehavior returnBehavior = super.handleAppendEntriesReply(sender, appendEntriesReply);
         tryToCompleteLeadershipTransfer(appendEntriesReply.getFollowerId());
         return returnBehavior;
@@ -103,20 +111,20 @@ public class Leader extends AbstractLeader {
      * <li>Start a timer (Stopwatch).</li>
      * <li>Send an initial AppendEntries heartbeat to all followers.</li>
      * <li>On AppendEntriesReply, check if the follower's new match Index matches the leader's last index</li>
-     * <li>If it matches, </li>
+     * <li>If it matches,
      *   <ul>
      *   <li>Send an additional AppendEntries to ensure the follower has applied all its log entries to its state.</li>
      *   <li>Send an ElectionTimeout to the follower to immediately start an election.</li>
      *   <li>Notify {@link RaftActorLeadershipTransferCohort#transferComplete}.</li>
-     *   </ul>
+     *   </ul></li>
      * <li>Otherwise if the election time out period elapses, notify
-     *     {@link RaftActorLeadershipTransferCohort#abortTtransfer}.</li>
+     *     {@link RaftActorLeadershipTransferCohort#abortTransfer}.</li>
      * </ul>
      *
-     * @param leadershipTransferCohort
+     * @param leadershipTransferCohort the cohort participating in the leadership transfer
      */
-    public void transferLeadership(@Nonnull RaftActorLeadershipTransferCohort leadershipTransferCohort) {
-        LOG.debug("{}: Attempting to transfer leadership", logName());
+    public void transferLeadership(@NonNull final RaftActorLeadershipTransferCohort leadershipTransferCohort) {
+        log.debug("{}: Attempting to transfer leadership", logName());
 
         leadershipTransferContext = new LeadershipTransferContext(leadershipTransferCohort);
 
@@ -124,34 +132,41 @@ public class Leader extends AbstractLeader {
         sendAppendEntries(0, false);
     }
 
-    private void tryToCompleteLeadershipTransfer(String followerId) {
-        if(leadershipTransferContext == null) {
+    private void tryToCompleteLeadershipTransfer(final String followerId) {
+        if (leadershipTransferContext == null) {
+            return;
+        }
+
+        final Optional<String> requestedFollowerIdOptional
+                = leadershipTransferContext.transferCohort.getRequestedFollowerId();
+        if (requestedFollowerIdOptional.isPresent() && !requestedFollowerIdOptional.get().equals(followerId)) {
+            // we want to transfer leadership to specific follower
             return;
         }
 
         FollowerLogInformation followerInfo = getFollower(followerId);
-        if(followerInfo == null) {
+        if (followerInfo == null) {
             return;
         }
 
         long lastIndex = context.getReplicatedLog().lastIndex();
         boolean isVoting = context.getPeerInfo(followerId).isVoting();
 
-        LOG.debug("{}: tryToCompleteLeadershipTransfer: followerId: {}, matchIndex: {}, lastIndex: {}, isVoting: {}",
+        log.debug("{}: tryToCompleteLeadershipTransfer: followerId: {}, matchIndex: {}, lastIndex: {}, isVoting: {}",
                 logName(), followerId, followerInfo.getMatchIndex(), lastIndex, isVoting);
 
-        if(isVoting && followerInfo.getMatchIndex() == lastIndex) {
-            LOG.debug("{}: Follower's log matches - sending ElectionTimeout", logName());
+        if (isVoting && followerInfo.getMatchIndex() == lastIndex) {
+            log.debug("{}: Follower's log matches - sending ElectionTimeout", logName());
 
             // We can't be sure if the follower has applied all its log entries to its state so send an
             // additional AppendEntries with the latest commit index.
             sendAppendEntries(0, false);
 
-            // Now send an ElectionTimeout to the matching follower to immediately start an election.
+            // Now send a TimeoutNow message to the matching follower to immediately start an election.
             ActorSelection followerActor = context.getPeerActorSelection(followerId);
-            followerActor.tell(ElectionTimeout.INSTANCE, context.getActor());
+            followerActor.tell(TimeoutNow.INSTANCE, context.getActor());
 
-            LOG.debug("{}: Leader transfer complete", logName());
+            log.debug("{}: Leader transfer complete", logName());
 
             leadershipTransferContext.transferCohort.transferComplete();
             leadershipTransferContext = null;
@@ -160,20 +175,22 @@ public class Leader extends AbstractLeader {
 
     @Override
     public void close() {
-        if(leadershipTransferContext != null) {
-            leadershipTransferContext.transferCohort.abortTransfer();
+        if (leadershipTransferContext != null) {
+            LeadershipTransferContext localLeadershipTransferContext = leadershipTransferContext;
+            leadershipTransferContext = null;
+            localLeadershipTransferContext.transferCohort.abortTransfer();
         }
 
         super.close();
     }
 
     @VisibleForTesting
-    void markFollowerActive(String followerId) {
+    void markFollowerActive(final String followerId) {
         getFollower(followerId).markFollowerActive();
     }
 
     @VisibleForTesting
-    void markFollowerInActive(String followerId) {
+    void markFollowerInActive(final String followerId) {
         getFollower(followerId).markFollowerInActive();
     }
 
@@ -181,12 +198,12 @@ public class Leader extends AbstractLeader {
         RaftActorLeadershipTransferCohort transferCohort;
         Stopwatch timer = Stopwatch.createStarted();
 
-        LeadershipTransferContext(RaftActorLeadershipTransferCohort transferCohort) {
+        LeadershipTransferContext(final RaftActorLeadershipTransferCohort transferCohort) {
             this.transferCohort = transferCohort;
         }
 
-        boolean isExpired(long timeout) {
-            if(timer.elapsed(TimeUnit.MILLISECONDS) >= timeout) {
+        boolean isExpired(final long timeout) {
+            if (timer.elapsed(TimeUnit.MILLISECONDS) >= timeout) {
                 transferCohort.abortTransfer();
                 return true;
             }