X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-akka-raft%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fraft%2Fbehaviors%2FAbstractRaftActorBehavior.java;h=0a553b40fd59aab555f258f897a2154830afd1c8;hb=6702aa8391498f647b7181fd971ca23674ac14d6;hp=fde104223bdafec77dcc5cfbcb8927f0b870fbcb;hpb=cf5be659d906cc80d52647cb516bbab435156742;p=controller.git

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
index fde104223b..0a553b40fd 100644
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
@@ -8,11 +8,27 @@
 
 package org.opendaylight.controller.cluster.raft.behaviors;
 
+import akka.actor.ActorRef;
+import akka.actor.Cancellable;
+import org.opendaylight.controller.cluster.raft.ClientRequestTracker;
 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.SerializationUtils;
+import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
+import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
+import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
+import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
+import org.opendaylight.controller.cluster.raft.messages.RequestVote;
+import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
+import scala.concurrent.duration.FiniteDuration;
+
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Abstract class that represents the behavior of a RaftActor
- * <p>
+ * <p/>
  * All Servers:
  * <ul>
  * <li> If commitIndex > lastApplied: increment lastApplied, apply
@@ -27,8 +43,311 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
      */
     protected final RaftActorContext context;
 
+    /**
+     *
+     */
+    private Cancellable electionCancel = null;
+
+    /**
+     *
+     */
+    protected String leaderId = null;
+
 
     protected AbstractRaftActorBehavior(RaftActorContext context) {
         this.context = context;
     }
+
+    /**
+     * Derived classes should not directly handle AppendEntries messages it
+     * should let the base class handle it first. Once the base class handles
+     * the AppendEntries message and does the common actions that are applicable
+     * in all RaftState's it will delegate the handling of the AppendEntries
+     * message to the derived class to do more state specific handling by calling
+     * this method
+     *
+     * @param sender         The actor that sent this message
+     * @param appendEntries  The AppendEntries message
+     * @return
+     */
+    protected abstract RaftState handleAppendEntries(ActorRef sender,
+        AppendEntries appendEntries);
+
+
+    /**
+     * appendEntries first processes the AppendEntries message and then
+     * delegates handling to a specific behavior
+     *
+     * @param sender
+     * @param appendEntries
+     * @return
+     */
+    protected RaftState appendEntries(ActorRef sender,
+        AppendEntries appendEntries) {
+
+        // 1. Reply false if term < currentTerm (§5.1)
+        if (appendEntries.getTerm() < currentTerm()) {
+            context.getLogger().debug(
+                "Cannot append entries because sender term " + appendEntries
+                    .getTerm() + " is less than " + currentTerm());
+            sender.tell(
+                new AppendEntriesReply(context.getId(), currentTerm(), false,
+                    lastIndex(), lastTerm()), actor()
+            );
+            return state();
+        }
+
+
+        return handleAppendEntries(sender, appendEntries);
+    }
+
+    /**
+     * Derived classes should not directly handle AppendEntriesReply messages it
+     * should let the base class handle it first. Once the base class handles
+     * the AppendEntriesReply message and does the common actions that are
+     * applicable in all RaftState's it will delegate the handling of the
+     * AppendEntriesReply message to the derived class to do more state specific
+     * handling by calling this method
+     *
+     * @param sender             The actor that sent this message
+     * @param appendEntriesReply The AppendEntriesReply message
+     * @return
+     */
+    protected abstract RaftState handleAppendEntriesReply(ActorRef sender,
+        AppendEntriesReply appendEntriesReply);
+
+    /**
+     * requestVote handles the RequestVote message. This logic is common
+     * for all behaviors
+     *
+     * @param sender
+     * @param requestVote
+     * @return
+     */
+    protected RaftState requestVote(ActorRef sender,
+        RequestVote requestVote) {
+
+        boolean grantVote = false;
+
+        //  Reply false if term < currentTerm (§5.1)
+        if (requestVote.getTerm() < currentTerm()) {
+            grantVote = false;
+
+            // If votedFor is null or candidateId, and candidate’s log is at
+            // least as up-to-date as receiver’s log, grant vote (§5.2, §5.4)
+        } else if (votedFor() == null || votedFor()
+            .equals(requestVote.getCandidateId())) {
+
+            boolean candidateLatest = false;
+
+            // From §5.4.1
+            // Raft determines which of two logs is more up-to-date
+            // by comparing the index and term of the last entries in the
+            // logs. If the logs have last entries with different terms, then
+            // the log with the later term is more up-to-date. If the logs
+            // end with the same term, then whichever log is longer is
+            // more up-to-date.
+            if (requestVote.getLastLogTerm() > lastTerm()) {
+                candidateLatest = true;
+            } else if ((requestVote.getLastLogTerm() == lastTerm())
+                && requestVote.getLastLogIndex() >= lastIndex()) {
+                candidateLatest = true;
+            }
+
+            if (candidateLatest) {
+                grantVote = true;
+                context.getTermInformation().updateAndPersist(requestVote.getTerm(),
+                    requestVote.getCandidateId());
+            }
+        }
+
+        sender.tell(new RequestVoteReply(currentTerm(), grantVote), actor());
+
+        return state();
+    }
+
+    /**
+     * Derived classes should not directly handle RequestVoteReply messages it
+     * should let the base class handle it first. Once the base class handles
+     * the RequestVoteReply message and does the common actions that are
+     * applicable in all RaftState's it will delegate the handling of the
+     * RequestVoteReply message to the derived class to do more state specific
+     * handling by calling this method
+     *
+     * @param sender           The actor that sent this message
+     * @param requestVoteReply The RequestVoteReply message
+     * @return
+     */
+    protected abstract RaftState handleRequestVoteReply(ActorRef sender,
+        RequestVoteReply requestVoteReply);
+
+    /**
+     * Creates a random election duration
+     *
+     * @return
+     */
+    protected FiniteDuration electionDuration() {
+        long variance = new Random().nextInt(context.getConfigParams().getElectionTimeVariance());
+        return context.getConfigParams().getElectionTimeOutInterval().$plus(
+            new FiniteDuration(variance, TimeUnit.MILLISECONDS));
+    }
+
+    /**
+     * stop the scheduled election
+     */
+    protected void stopElection() {
+        if (electionCancel != null && !electionCancel.isCancelled()) {
+            electionCancel.cancel();
+        }
+    }
+
+    /**
+     * schedule a new election
+     *
+     * @param interval
+     */
+    protected void scheduleElection(FiniteDuration interval) {
+        stopElection();
+
+        // Schedule an election. When the scheduler triggers an ElectionTimeout
+        // message is sent to itself
+        electionCancel =
+            context.getActorSystem().scheduler().scheduleOnce(interval,
+                context.getActor(), new ElectionTimeout(),
+                context.getActorSystem().dispatcher(), context.getActor());
+    }
+
+    /**
+     * Get the current term
+     * @return
+     */
+    protected long currentTerm() {
+        return context.getTermInformation().getCurrentTerm();
+    }
+
+    /**
+     * Get the candidate for whom we voted in the current term
+     * @return
+     */
+    protected String votedFor() {
+        return context.getTermInformation().getVotedFor();
+    }
+
+    /**
+     * Get the actor associated with this behavior
+     * @return
+     */
+    protected ActorRef actor() {
+        return context.getActor();
+    }
+
+    /**
+     * Get the term from the last entry in the log
+     *
+     * @return
+     */
+    protected long lastTerm() {
+        return context.getReplicatedLog().lastTerm();
+    }
+
+    /**
+     * Get the index from the last entry in the log
+     *
+     * @return
+     */
+    protected long lastIndex() {
+        return context.getReplicatedLog().lastIndex();
+    }
+
+    /**
+     * Find the client request tracker for a specific logIndex
+     *
+     * @param logIndex
+     * @return
+     */
+    protected ClientRequestTracker findClientRequestTracker(long logIndex) {
+        return null;
+    }
+
+    /**
+     * Find the log index from the previous to last entry in the log
+     *
+     * @return
+     */
+    protected long prevLogIndex(long index){
+        ReplicatedLogEntry prevEntry =
+            context.getReplicatedLog().get(index - 1);
+        if (prevEntry != null) {
+            return prevEntry.getIndex();
+        }
+        return -1;
+    }
+
+    /**
+     * Find the log term from the previous to last entry in the log
+     * @return
+     */
+    protected long prevLogTerm(long index){
+        ReplicatedLogEntry prevEntry =
+            context.getReplicatedLog().get(index - 1);
+        if (prevEntry != null) {
+            return prevEntry.getTerm();
+        }
+        return -1;
+    }
+
+    /**
+     * Apply the provided index to the state machine
+     *
+     * @param index a log index that is known to be committed
+     */
+    protected void applyLogToStateMachine(long index) {
+        // Now maybe we apply to the state machine
+        for (long i = context.getLastApplied() + 1;
+             i < index + 1; i++) {
+            ActorRef clientActor = null;
+            String identifier = null;
+            ClientRequestTracker tracker = findClientRequestTracker(i);
+
+            if (tracker != null) {
+                clientActor = tracker.getClientActor();
+                identifier = tracker.getIdentifier();
+            }
+            ReplicatedLogEntry replicatedLogEntry =
+                context.getReplicatedLog().get(i);
+
+            if (replicatedLogEntry != null) {
+                actor().tell(new ApplyState(clientActor, identifier,
+                    replicatedLogEntry), actor());
+            } else {
+                context.getLogger().error(
+                    "Missing index " + i + " from log. Cannot apply state.");
+            }
+        }
+        // Send a local message to the local RaftActor (it's derived class to be
+        // specific to apply the log to it's index)
+        context.setLastApplied(index);
+    }
+
+    protected Object fromSerializableMessage(Object serializable){
+        return SerializationUtils.fromSerializable(serializable);
+    }
+
+    @Override
+    public RaftState handleMessage(ActorRef sender, Object message) {
+        if (message instanceof AppendEntries) {
+            return appendEntries(sender, (AppendEntries) message);
+        } else if (message instanceof AppendEntriesReply) {
+            return handleAppendEntriesReply(sender, (AppendEntriesReply) message);
+        } else if (message instanceof RequestVote) {
+            return requestVote(sender, (RequestVote) message);
+        } else if (message instanceof RequestVoteReply) {
+            return handleRequestVoteReply(sender, (RequestVoteReply) message);
+        }
+        return state();
+    }
+
+    @Override public String getLeaderId() {
+        return leaderId;
+    }
 }