--- /dev/null
+/*
+ * Copyright (c) 2015 Brocade Communications Systems, Inc. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.cluster.raft.behaviors;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.dispatch.Dispatchers;
+import akka.testkit.JavaTestKit;
+import akka.testkit.TestActorRef;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.util.concurrent.Uninterruptibles;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.junit.After;
+import org.junit.Test;
+import org.opendaylight.controller.cluster.raft.DefaultConfigParamsImpl;
+import org.opendaylight.controller.cluster.raft.MockRaftActorContext;
+import org.opendaylight.controller.cluster.raft.MockRaftActorContext.MockPayload;
+import org.opendaylight.controller.cluster.raft.MockRaftActorContext.MockReplicatedLogEntry;
+import org.opendaylight.controller.cluster.raft.MockRaftActorContext.SimpleReplicatedLog;
+import org.opendaylight.controller.cluster.raft.RaftActorContext;
+import org.opendaylight.controller.cluster.raft.RaftState;
+import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
+import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat;
+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 org.opendaylight.controller.cluster.raft.utils.MessageCollectorActor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.slf4j.impl.SimpleLogger;
+import scala.concurrent.duration.FiniteDuration;
+
+/**
+ * Tests various leader election scenarios.
+ *
+ * @author Thomas Pantelis
+ */
+public class LeaderElectionScenariosTest {
+
+ private static final int HEARTBEAT_INTERVAL = 50;
+
+ public static class MemberActor extends MessageCollectorActor {
+
+ volatile RaftActorBehavior behavior;
+ Map<Class<?>, CountDownLatch> messagesReceivedLatches = new ConcurrentHashMap<>();
+ Map<Class<?>, Boolean> dropMessagesToBehavior = new ConcurrentHashMap<>();
+ CountDownLatch behaviorStateChangeLatch;
+
+ public static Props props() {
+ return Props.create(MemberActor.class).withDispatcher(Dispatchers.DefaultDispatcherId());
+ }
+
+ @Override
+ public void onReceive(Object message) throws Exception {
+ // Ignore scheduled SendHeartBeat messages.
+ if(message instanceof SendHeartBeat) {
+ return;
+ }
+
+ try {
+ if(behavior != null && !dropMessagesToBehavior.containsKey(message.getClass())) {
+ RaftActorBehavior oldBehavior = behavior;
+ behavior = behavior.handleMessage(getSender(), message);
+ if(behavior != oldBehavior && behaviorStateChangeLatch != null) {
+ behaviorStateChangeLatch.countDown();
+ }
+ }
+ } finally {
+ super.onReceive(message);
+
+ CountDownLatch latch = messagesReceivedLatches.get(message.getClass());
+ if(latch != null) {
+ latch.countDown();
+ }
+ }
+ }
+
+ void expectBehaviorStateChange() {
+ behaviorStateChangeLatch = new CountDownLatch(1);
+ }
+
+ void waitForBehaviorStateChange() {
+ assertTrue("Expected behavior state change",
+ Uninterruptibles.awaitUninterruptibly(behaviorStateChangeLatch, 5, TimeUnit.SECONDS));
+ }
+
+ void expectMessageClass(Class<?> expClass, int expCount) {
+ messagesReceivedLatches.put(expClass, new CountDownLatch(expCount));
+ }
+
+ void waitForExpectedMessages(Class<?> expClass) {
+ CountDownLatch latch = messagesReceivedLatches.get(expClass);
+ assertNotNull("No messages received for " + expClass, latch);
+ assertTrue("Missing messages of type " + expClass,
+ Uninterruptibles.awaitUninterruptibly(latch, 5, TimeUnit.SECONDS));
+ }
+
+ void dropMessagesToBehavior(Class<?> msgClass) {
+ dropMessagesToBehavior(msgClass, 1);
+ }
+
+ void dropMessagesToBehavior(Class<?> msgClass, int expCount) {
+ expectMessageClass(msgClass, expCount);
+ dropMessagesToBehavior.put(msgClass, Boolean.TRUE);
+ }
+
+ void clearDropMessagesToBehavior() {
+ dropMessagesToBehavior.clear();
+ }
+
+ @Override
+ public void clear() {
+ behaviorStateChangeLatch = null;
+ clearDropMessagesToBehavior();
+ messagesReceivedLatches.clear();
+ super.clear();
+ }
+
+ void forwardCapturedMessageToBehavior(Class<?> msgClass, ActorRef sender) throws Exception {
+ Object message = getFirstMatching(getSelf(), msgClass);
+ assertNotNull("Message of type " + msgClass + " not received", message);
+ getSelf().tell(message, sender);
+ }
+
+ void forwardCapturedMessagesToBehavior(Class<?> msgClass, ActorRef sender) throws Exception {
+ for(Object m: getAllMatching(getSelf(), msgClass)) {
+ getSelf().tell(m, sender);
+ }
+ }
+
+ <T> T getCapturedMessage(Class<T> msgClass) throws Exception {
+ Object message = getFirstMatching(getSelf(), msgClass);
+ assertNotNull("Message of type " + msgClass + " not received", message);
+ return (T) message;
+ }
+ }
+
+ static {
+ System.setProperty(SimpleLogger.LOG_KEY_PREFIX + MockRaftActorContext.class.getName(), "trace");
+ }
+
+ private final Logger testLog = LoggerFactory.getLogger(MockRaftActorContext.class);
+ private final ActorSystem system = ActorSystem.create("test");
+
+ @After
+ public void tearDown() {
+ JavaTestKit.shutdownActorSystem(system);
+ }
+
+ private DefaultConfigParamsImpl newConfigParams() {
+ DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
+ configParams.setHeartBeatInterval(new FiniteDuration(HEARTBEAT_INTERVAL, TimeUnit.MILLISECONDS));
+ configParams.setElectionTimeoutFactor(100000);
+ configParams.setIsolatedLeaderCheckInterval(new FiniteDuration(1, TimeUnit.DAYS));
+ return configParams;
+ }
+
+ private MockRaftActorContext newRaftActorContext(String id, ActorRef actor,
+ Map<String, String> peerAddresses) {
+ MockRaftActorContext context = new MockRaftActorContext(id, system, actor);
+ context.setPeerAddresses(peerAddresses);
+ context.getTermInformation().updateAndPersist(1, "");
+ return context;
+ }
+
+ private void verifyBehaviorState(String name, TestActorRef<MemberActor> actor, RaftState expState) {
+ assertEquals(name + " behavior state", expState, actor.underlyingActor().behavior.state());
+ }
+
+ private void initializeLeaderBehavior(TestActorRef<MemberActor> actor, RaftActorContext context,
+ int numActiveFollowers) throws Exception {
+ // Leader sends immediate heartbeats - we don't care about it so ignore it.
+
+ actor.underlyingActor().expectMessageClass(AppendEntriesReply.class, numActiveFollowers);
+ Leader leader = new Leader(context);
+ actor.underlyingActor().waitForExpectedMessages(AppendEntriesReply.class);
+ actor.underlyingActor().behavior = leader;
+
+ actor.underlyingActor().forwardCapturedMessagesToBehavior(AppendEntriesReply.class, ActorRef.noSender());
+ actor.underlyingActor().clear();
+ }
+
+ private TestActorRef<MemberActor> newMemberActor(String name) throws Exception {
+ TestActorRef<MemberActor> actor = TestActorRef.create(system, MemberActor.props(), name);
+ MessageCollectorActor.waitUntilReady(actor);
+ return actor;
+ }
+
+ private void sendHeartbeat(TestActorRef<MemberActor> leaderActor) {
+ Uninterruptibles.sleepUninterruptibly(HEARTBEAT_INTERVAL, TimeUnit.MILLISECONDS);
+ leaderActor.underlyingActor().behavior.handleMessage(leaderActor, new SendHeartBeat());
+ }
+
+ @Test
+ public void testDelayedMessagesScenario() throws Exception {
+ testLog.info("Starting testDelayedMessagesScenario");
+
+ TestActorRef<MemberActor> member1Actor = newMemberActor("member1");
+ TestActorRef<MemberActor> member2Actor = newMemberActor("member2");
+ TestActorRef<MemberActor> member3Actor = newMemberActor("member3");
+
+ // Create member 2's behavior initially as Follower
+
+ MockRaftActorContext member2Context = newRaftActorContext("member2", member2Actor,
+ ImmutableMap.<String,String>builder().
+ put("member1", member1Actor.path().toString()).
+ put("member3", member3Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member2ConfigParams = newConfigParams();
+ member2Context.setConfigParams(member2ConfigParams);
+
+ Follower member2Behavior = new Follower(member2Context);
+ member2Actor.underlyingActor().behavior = member2Behavior;
+
+ // Create member 3's behavior initially as Follower
+
+ MockRaftActorContext member3Context = newRaftActorContext("member3", member3Actor,
+ ImmutableMap.<String,String>builder().
+ put("member1", member1Actor.path().toString()).
+ put("member2", member2Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member3ConfigParams = newConfigParams();
+ member3Context.setConfigParams(member3ConfigParams);
+
+ Follower member3Behavior = new Follower(member3Context);
+ member3Actor.underlyingActor().behavior = member3Behavior;
+
+ // Create member 1's behavior initially as Leader
+
+ MockRaftActorContext member1Context = newRaftActorContext("member1", member1Actor,
+ ImmutableMap.<String,String>builder().
+ put("member2", member2Actor.path().toString()).
+ put("member3", member3Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member1ConfigParams = newConfigParams();
+ member1Context.setConfigParams(member1ConfigParams);
+
+ initializeLeaderBehavior(member1Actor, member1Context, 2);
+
+ member2Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().clear();
+
+ // Send ElectionTimeout to member 2 to simulate missing heartbeat from the Leader. member 2
+ // should switch to Candidate and send out RequestVote messages. Set member 1 and 3 actors
+ // to capture RequestVote but not to forward to the behavior just yet as we want to
+ // control the order of RequestVote messages to member 1 and 3.
+
+ member1Actor.underlyingActor().dropMessagesToBehavior(RequestVote.class);
+
+ member2Actor.underlyingActor().expectBehaviorStateChange();
+
+ member3Actor.underlyingActor().dropMessagesToBehavior(RequestVote.class);
+
+ member2Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+
+ member1Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+
+ member2Actor.underlyingActor().waitForBehaviorStateChange();
+ verifyBehaviorState("member 2", member2Actor, RaftState.Candidate);
+
+ assertEquals("member 1 election term", 1, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 2, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 1, member3Context.getTermInformation().getCurrentTerm());
+
+ // At this point member 1 and 3 actors have captured the RequestVote messages. First
+ // forward the RequestVote message to member 1's behavior. Since the RequestVote term
+ // is greater than member 1's term, member 1 should switch to Follower without replying
+ // to RequestVote and update its term to 2.
+
+ member1Actor.underlyingActor().clearDropMessagesToBehavior();
+ member1Actor.underlyingActor().expectBehaviorStateChange();
+ member1Actor.underlyingActor().forwardCapturedMessageToBehavior(RequestVote.class, member2Actor);
+ member1Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+
+ member1Actor.underlyingActor().waitForBehaviorStateChange();
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+
+ // Now forward member 3's captured RequestVote message to its behavior. Since member 3 is
+ // already a Follower, it should update its term to 2 and send a RequestVoteReply back to
+ // member 2 granting the vote b/c the RequestVote's term, lastLogTerm, and lastLogIndex
+ // should satisfy the criteria for granting the vote. However, we'll delay sending the
+ // RequestVoteReply to member 2's behavior to simulate network latency.
+
+ member2Actor.underlyingActor().dropMessagesToBehavior(RequestVoteReply.class);
+
+ member3Actor.underlyingActor().clearDropMessagesToBehavior();
+ member3Actor.underlyingActor().expectMessageClass(RequestVote.class, 1);
+ member3Actor.underlyingActor().forwardCapturedMessageToBehavior(RequestVote.class, member2Actor);
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Follower);
+
+ assertEquals("member 1 election term", 2, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 2, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 2, member3Context.getTermInformation().getCurrentTerm());
+
+ // Send ElectionTimeout to member 3 to simulate missing heartbeat from a Leader. member 3
+ // should switch to Candidate and send out RequestVote messages. member 1 should grant the
+ // vote and send a reply. After receiving the RequestVoteReply, member 3 should switch to leader.
+
+ member2Actor.underlyingActor().expectBehaviorStateChange();
+ member3Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().expectMessageClass(RequestVoteReply.class, 1);
+ member3Actor.underlyingActor().expectMessageClass(AppendEntriesReply.class, 2);
+
+ member3Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVoteReply.class);
+
+ RequestVoteReply requestVoteReply = member3Actor.underlyingActor().getCapturedMessage(RequestVoteReply.class);
+ assertEquals("getTerm", member3Context.getTermInformation().getCurrentTerm(), requestVoteReply.getTerm());
+ assertEquals("isVoteGranted", true, requestVoteReply.isVoteGranted());
+
+ verifyBehaviorState("member 3", member3Actor, RaftState.Leader);
+
+ // member 2 should've switched to Follower as member 3's RequestVote term (3) was greater
+ // than member 2's term (2).
+
+ member2Actor.underlyingActor().waitForBehaviorStateChange();
+ verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
+
+ // The switch to leader should cause an immediate AppendEntries heartbeat from member 3.
+
+ member3Actor.underlyingActor().waitForExpectedMessages(AppendEntriesReply.class);
+
+ assertEquals("member 1 election term", 3, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 3, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 3, member3Context.getTermInformation().getCurrentTerm());
+
+ // Now forward the original delayed RequestVoteReply from member 3 to member 2 that granted
+ // the vote. Since member 2 is now a Follower, the RequestVoteReply should be ignored.
+
+ member2Actor.underlyingActor().clearDropMessagesToBehavior();
+ member2Actor.underlyingActor().forwardCapturedMessageToBehavior(RequestVoteReply.class, member3Actor);
+
+ member2Actor.underlyingActor().waitForExpectedMessages(RequestVoteReply.class);
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Leader);
+
+ assertEquals("member 1 election term", 3, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 3, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 3, member3Context.getTermInformation().getCurrentTerm());
+
+ testLog.info("testDelayedMessagesScenario done");
+ }
+
+ @Test
+ public void testPartitionedLeadersScenario() throws Exception {
+ testLog.info("Starting testPartitionedLeadersScenario");
+
+ TestActorRef<MemberActor> member1Actor = newMemberActor("member1");
+ TestActorRef<MemberActor> member2Actor = newMemberActor("member2");
+ TestActorRef<MemberActor> member3Actor = newMemberActor("member3");
+
+ // Create member 2's behavior initially as Follower
+
+ MockRaftActorContext member2Context = newRaftActorContext("member2", member2Actor,
+ ImmutableMap.<String,String>builder().
+ put("member1", member1Actor.path().toString()).
+ put("member3", member3Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member2ConfigParams = newConfigParams();
+ member2Context.setConfigParams(member2ConfigParams);
+
+ Follower member2Behavior = new Follower(member2Context);
+ member2Actor.underlyingActor().behavior = member2Behavior;
+
+ // Create member 3's behavior initially as Follower
+
+ MockRaftActorContext member3Context = newRaftActorContext("member3", member3Actor,
+ ImmutableMap.<String,String>builder().
+ put("member1", member1Actor.path().toString()).
+ put("member2", member2Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member3ConfigParams = newConfigParams();
+ member3Context.setConfigParams(member3ConfigParams);
+
+ Follower member3Behavior = new Follower(member3Context);
+ member3Actor.underlyingActor().behavior = member3Behavior;
+
+ // Create member 1's behavior initially as Leader
+
+ MockRaftActorContext member1Context = newRaftActorContext("member1", member1Actor,
+ ImmutableMap.<String,String>builder().
+ put("member2", member2Actor.path().toString()).
+ put("member3", member3Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member1ConfigParams = newConfigParams();
+ member1Context.setConfigParams(member1ConfigParams);
+
+ initializeLeaderBehavior(member1Actor, member1Context, 2);
+
+ member2Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().clear();
+
+ // Send ElectionTimeout to member 2 to simulate no heartbeat from the Leader (member 1).
+ // member 2 should switch to Candidate, start new term 2 and send out RequestVote messages.
+ // member 1 will switch to Follower b/c its term is less than the RequestVote term, also it
+ // won't send back a reply. member 3 will drop the message (ie won't forward it to its behavior) to
+ // simulate loss of network connectivity between member 2 and 3.
+
+ member1Actor.underlyingActor().expectMessageClass(RequestVote.class, 1);
+
+ member2Actor.underlyingActor().expectBehaviorStateChange();
+
+ member3Actor.underlyingActor().dropMessagesToBehavior(RequestVote.class);
+
+ member2Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+
+ member1Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+
+ // member 1 should switch to Follower as the RequestVote term is greater than its term. It
+ // won't send back a RequestVoteReply in this case.
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+
+ // member 2 should switch to Candidate since member 1 didn't reply.
+
+ member2Actor.underlyingActor().waitForBehaviorStateChange();
+ verifyBehaviorState("member 2", member2Actor, RaftState.Candidate);
+
+ assertEquals("member 1 election term", 2, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 2, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 1, member3Context.getTermInformation().getCurrentTerm());
+
+ // Send ElectionTimeout to member 3 to simulate no heartbeat from the Leader (member 1).
+ // member 2 should switch to Candidate and send out RequestVote messages. member 1 will reply and
+ // grant the vote but member 2 will drop the message to simulate loss of network connectivity.
+
+ member1Actor.underlyingActor().clear();
+ member1Actor.underlyingActor().expectMessageClass(RequestVote.class, 1);
+ member1Actor.underlyingActor().expectMessageClass(AppendEntries.class, 1);
+
+ member2Actor.underlyingActor().clear();
+ member2Actor.underlyingActor().dropMessagesToBehavior(RequestVote.class);
+ member2Actor.underlyingActor().dropMessagesToBehavior(AppendEntries.class);
+
+ member3Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().expectMessageClass(RequestVoteReply.class, 1);
+ member3Actor.underlyingActor().expectMessageClass(AppendEntriesReply.class, 1);
+
+ member3Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+
+ member1Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ member2Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVoteReply.class);
+
+ RequestVoteReply requestVoteReply = member3Actor.underlyingActor().getCapturedMessage(RequestVoteReply.class);
+ assertEquals("getTerm", member3Context.getTermInformation().getCurrentTerm(), requestVoteReply.getTerm());
+ assertEquals("isVoteGranted", true, requestVoteReply.isVoteGranted());
+
+ // when member 3 switches to Leader it will immediately send out heartbeat AppendEntries to
+ // the followers. Wait for AppendEntries to member 1 and its AppendEntriesReply. The
+ // AppendEntries message to member 2 is dropped.
+
+ member1Actor.underlyingActor().waitForExpectedMessages(AppendEntries.class);
+ member2Actor.underlyingActor().waitForExpectedMessages(AppendEntries.class);
+ member3Actor.underlyingActor().waitForExpectedMessages(AppendEntriesReply.class);
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Candidate);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Leader);
+
+ assertEquals("member 1 election term", 2, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 2, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 2, member3Context.getTermInformation().getCurrentTerm());
+
+ // member 2 is partitioned from the Leader (member 3) and hasn't received any messages. It
+ // would get another ElectionTimeout so simulate that. member 1 should send back a reply
+ // granting the vote. Messages (RequestVote and AppendEntries) from member 2 to member 3
+ // are dropped to simulate loss of network connectivity. Note member 2 will increment its
+ // election term to 3.
+
+ member1Actor.underlyingActor().clear();
+ member1Actor.underlyingActor().expectMessageClass(AppendEntries.class, 1);
+
+ member2Actor.underlyingActor().clear();
+ member2Actor.underlyingActor().expectMessageClass(RequestVoteReply.class, 1);
+ member2Actor.underlyingActor().expectMessageClass(AppendEntriesReply.class, 1);
+
+ member3Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().dropMessagesToBehavior(AppendEntries.class);
+ member3Actor.underlyingActor().dropMessagesToBehavior(RequestVote.class);
+
+ member2Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+
+ member2Actor.underlyingActor().waitForExpectedMessages(RequestVoteReply.class);
+
+ requestVoteReply = member2Actor.underlyingActor().getCapturedMessage(RequestVoteReply.class);
+ assertEquals("getTerm", member2Context.getTermInformation().getCurrentTerm(), requestVoteReply.getTerm());
+ assertEquals("isVoteGranted", true, requestVoteReply.isVoteGranted());
+
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+
+ member1Actor.underlyingActor().waitForExpectedMessages(AppendEntries.class);
+ member3Actor.underlyingActor().waitForExpectedMessages(AppendEntries.class);
+ member2Actor.underlyingActor().waitForExpectedMessages(AppendEntriesReply.class);
+
+ // We end up with 2 partitioned leaders both leading member 1. The term for member 1 and 3
+ // is 3 and member 3's term is 2.
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Leader);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Leader);
+
+ assertEquals("member 1 election term", 3, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 3, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 2, member3Context.getTermInformation().getCurrentTerm());
+
+ // Re-establish connectivity between member 2 and 3, ie stop dropping messages between
+ // the 2. Send heartbeats (AppendEntries) from member 3. Both member 1 and 2 should send back
+ // an unsuccessful AppendEntriesReply b/c their term (3) is greater than member 3's term (2).
+ // This should cause member 3 to switch to Follower.
+
+ RaftActorBehavior savedMember1Behavior = member1Actor.underlyingActor().behavior;
+ RaftActorBehavior savedMember2Behavior = member2Actor.underlyingActor().behavior;
+ RaftActorBehavior savedMember3Behavior = member3Actor.underlyingActor().behavior;
+ long savedMember3Term = member3Context.getTermInformation().getCurrentTerm();
+ String savedMember3VoterFor = member3Context.getTermInformation().getVotedFor();
+
+ member1Actor.underlyingActor().clear();
+ member1Actor.underlyingActor().expectMessageClass(AppendEntries.class, 1);
+
+ member2Actor.underlyingActor().clear();
+ member2Actor.underlyingActor().expectMessageClass(AppendEntries.class, 1);
+
+ member3Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().expectMessageClass(AppendEntriesReply.class, 1);
+
+ sendHeartbeat(member3Actor);
+
+ member3Actor.underlyingActor().waitForExpectedMessages(AppendEntriesReply.class);
+
+ AppendEntriesReply appendEntriesReply = member3Actor.underlyingActor().
+ getCapturedMessage(AppendEntriesReply.class);
+ assertEquals("isSuccess", false, appendEntriesReply.isSuccess());
+ assertEquals("getTerm", 3, appendEntriesReply.getTerm());
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Leader);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Follower);
+
+ assertEquals("member 1 election term", 3, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 3, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 3, member3Context.getTermInformation().getCurrentTerm());
+
+ // Revert back to the partitioned leaders state to test the other sequence where member 2
+ // sends heartbeats first before member 3. member 1 should return a successful
+ // AppendEntriesReply b/c his term matches member 2's. member 3 should switch to Follower
+ // as his term is less than member 2's.
+
+ member1Actor.underlyingActor().behavior = savedMember1Behavior;
+ member2Actor.underlyingActor().behavior = savedMember2Behavior;
+ member3Actor.underlyingActor().behavior = savedMember3Behavior;
+
+ member3Context.getTermInformation().update(savedMember3Term, savedMember3VoterFor);
+
+ member1Actor.underlyingActor().clear();
+ member1Actor.underlyingActor().expectMessageClass(AppendEntries.class, 1);
+
+ member2Actor.underlyingActor().clear();
+ member2Actor.underlyingActor().expectMessageClass(AppendEntriesReply.class, 1);
+
+ member3Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().expectMessageClass(AppendEntries.class, 1);
+
+ sendHeartbeat(member2Actor);
+
+ member1Actor.underlyingActor().waitForExpectedMessages(AppendEntries.class);
+ member3Actor.underlyingActor().waitForExpectedMessages(AppendEntries.class);
+
+ member2Actor.underlyingActor().waitForExpectedMessages(AppendEntriesReply.class);
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Leader);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Follower);
+
+ assertEquals("member 1 election term", 3, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 3, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", 3, member3Context.getTermInformation().getCurrentTerm());
+
+ testLog.info("testPartitionedLeadersScenario done");
+ }
+
+ @Test
+ public void testPartitionedCandidateOnStartupScenario() throws Exception {
+ testLog.info("Starting testPartitionedCandidateOnStartupScenario");
+
+ TestActorRef<MemberActor> member1Actor = newMemberActor("member1") ;
+ TestActorRef<MemberActor> member2Actor = newMemberActor("member2");
+ TestActorRef<MemberActor> member3Actor = newMemberActor("member3");
+
+ // Create member 2's behavior as Follower.
+
+ MockRaftActorContext member2Context = newRaftActorContext("member2", member2Actor,
+ ImmutableMap.<String,String>builder().
+ put("member1", member1Actor.path().toString()).
+ put("member3", member3Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member2ConfigParams = newConfigParams();
+ member2Context.setConfigParams(member2ConfigParams);
+
+ Follower member2Behavior = new Follower(member2Context);
+ member2Actor.underlyingActor().behavior = member2Behavior;
+
+ // Create member 1's behavior as Leader.
+
+ MockRaftActorContext member1Context = newRaftActorContext("member1", member1Actor,
+ ImmutableMap.<String,String>builder().
+ put("member2", member2Actor.path().toString()).
+ put("member3", member3Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member1ConfigParams = newConfigParams();
+ member1Context.setConfigParams(member1ConfigParams);
+
+ initializeLeaderBehavior(member1Actor, member1Context, 1);
+
+ member2Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().clear();
+
+ // Initialize the ReplicatedLog and election term info for member 1 and 2. The current term
+ // will be 3 and the last term will be 2.
+
+ SimpleReplicatedLog replicatedLog = new SimpleReplicatedLog();
+ replicatedLog.append(new MockReplicatedLogEntry(2, 1, new MockPayload("")));
+ replicatedLog.append(new MockReplicatedLogEntry(3, 1, new MockPayload("")));
+
+ member1Context.setReplicatedLog(replicatedLog);
+ member1Context.getTermInformation().update(3, "");
+
+ member2Context.setReplicatedLog(replicatedLog);
+ member2Context.getTermInformation().update(3, member1Context.getId());
+
+ // Create member 3's behavior initially as a Candidate.
+
+ MockRaftActorContext member3Context = newRaftActorContext("member3", member3Actor,
+ ImmutableMap.<String,String>builder().
+ put("member1", member1Actor.path().toString()).
+ put("member2", member2Actor.path().toString()).build());
+
+ DefaultConfigParamsImpl member3ConfigParams = newConfigParams();
+ member3Context.setConfigParams(member3ConfigParams);
+
+ // Initialize the ReplicatedLog and election term info for Candidate member 3. The current term
+ // will be 2 and the last term will be 1 so it is behind the leader's log.
+
+ SimpleReplicatedLog candidateReplicatedLog = new SimpleReplicatedLog();
+ candidateReplicatedLog.append(new MockReplicatedLogEntry(1, 1, new MockPayload("")));
+ candidateReplicatedLog.append(new MockReplicatedLogEntry(2, 1, new MockPayload("")));
+
+ member3Context.setReplicatedLog(candidateReplicatedLog);
+ member3Context.getTermInformation().update(2, member1Context.getId());
+
+ // The member 3 Candidate will start a new term and send RequestVotes. However it will be
+ // partitioned from the cluster by having member 1 and 2 drop its RequestVote messages.
+
+ int numCandidateElections = 5;
+ long candidateElectionTerm = member3Context.getTermInformation().getCurrentTerm() + numCandidateElections;
+
+ member1Actor.underlyingActor().dropMessagesToBehavior(RequestVote.class, numCandidateElections);
+
+ member2Actor.underlyingActor().dropMessagesToBehavior(RequestVote.class, numCandidateElections);
+
+ Candidate member3Behavior = new Candidate(member3Context);
+ member3Actor.underlyingActor().behavior = member3Behavior;
+
+ // Send several additional ElectionTimeouts to Candidate member 3. Each ElectionTimeout will
+ // start a new term so Candidate member 3's current term will be greater than the leader's
+ // current term.
+
+ for(int i = 0; i < numCandidateElections - 1; i++) {
+ member3Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+ }
+
+ member1Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ member2Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Leader);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Candidate);
+
+ assertEquals("member 1 election term", 3, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", 3, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", candidateElectionTerm,
+ member3Context.getTermInformation().getCurrentTerm());
+
+ // Now send a couple more ElectionTimeouts to Candidate member 3 with the partition resolved.
+ //
+ // On the first RequestVote, Leader member 1 should switch to Follower as its term (s) is less than
+ // the RequestVote's term (8) from member 3. No RequestVoteReply should be sent by member 1.
+ // Follower member 2 should update its term since it less than the RequestVote's term and
+ // should return a RequestVoteReply but should not grant the vote as its last term and index
+ // is greater than the RequestVote's lastLogTerm and lastLogIndex, ie member 2's log is later
+ // or more up to date than member 3's.
+ //
+ // On the second RequestVote, both member 1 and 2 are followers so they should update their
+ // term and return a RequestVoteReply but should not grant the vote.
+
+ candidateElectionTerm += 2;
+ for(int i = 0; i < 2; i++) {
+ member1Actor.underlyingActor().clear();
+ member1Actor.underlyingActor().expectMessageClass(RequestVote.class, 1);
+ member2Actor.underlyingActor().clear();
+ member2Actor.underlyingActor().expectMessageClass(RequestVote.class, 1);
+ member3Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().expectMessageClass(RequestVoteReply.class, 1);
+
+ member3Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+
+ member1Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ member2Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVoteReply.class);
+
+ RequestVoteReply requestVoteReply = member3Actor.underlyingActor().getCapturedMessage(RequestVoteReply.class);
+ assertEquals("getTerm", member3Context.getTermInformation().getCurrentTerm(), requestVoteReply.getTerm());
+ assertEquals("isVoteGranted", false, requestVoteReply.isVoteGranted());
+ }
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Candidate);
+
+ // Even though member 3 didn't get voted for, member 1 and 2 should have updated their term
+ // to member 3's.
+
+ assertEquals("member 1 election term", candidateElectionTerm,
+ member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", candidateElectionTerm,
+ member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", candidateElectionTerm,
+ member3Context.getTermInformation().getCurrentTerm());
+
+ // At this point we have no leader. Candidate member 3 would continue to start new elections
+ // but wouldn't be granted a vote. One of the 2 followers would eventually time out from
+ // not having received a heartbeat from a leader and switch to candidate and start a new
+ // election. We'll simulate that here by sending an ElectionTimeout to member 1.
+
+ member1Actor.underlyingActor().clear();
+ member1Actor.underlyingActor().expectMessageClass(RequestVoteReply.class, 1);
+ member2Actor.underlyingActor().clear();
+ member2Actor.underlyingActor().expectMessageClass(RequestVote.class, 1);
+ member3Actor.underlyingActor().clear();
+ member3Actor.underlyingActor().expectMessageClass(RequestVote.class, 1);
+ member3Actor.underlyingActor().expectBehaviorStateChange();
+
+ member1Actor.tell(new ElectionTimeout(), ActorRef.noSender());
+
+ member2Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+ member3Actor.underlyingActor().waitForExpectedMessages(RequestVote.class);
+
+ // The RequestVoteReply should come from Follower member 2 and the vote should be granted
+ // since member 2's last term and index matches member 1's.
+
+ member1Actor.underlyingActor().waitForExpectedMessages(RequestVoteReply.class);
+
+ RequestVoteReply requestVoteReply = member1Actor.underlyingActor().getCapturedMessage(RequestVoteReply.class);
+ assertEquals("getTerm", member1Context.getTermInformation().getCurrentTerm(), requestVoteReply.getTerm());
+ assertEquals("isVoteGranted", true, requestVoteReply.isVoteGranted());
+
+ // Candidate member 3 should change to follower as its term should be less than the
+ // RequestVote term (member 1 started a new term higher than the other member's terms).
+
+ member3Actor.underlyingActor().waitForBehaviorStateChange();
+
+ verifyBehaviorState("member 1", member1Actor, RaftState.Leader);
+ verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
+ verifyBehaviorState("member 3", member3Actor, RaftState.Follower);
+
+ // newTerm should be 10.
+
+ long newTerm = candidateElectionTerm + 1;
+ assertEquals("member 1 election term", newTerm, member1Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 2 election term", newTerm, member2Context.getTermInformation().getCurrentTerm());
+ assertEquals("member 3 election term", newTerm, member3Context.getTermInformation().getCurrentTerm());
+
+ testLog.info("testPartitionedCandidateOnStartupScenario done");
+ }
+}
Code Review / controller.git / commitdiff