[incubator-ratis] branch master updated: RATIS-982. Fix RaftServerImpl illegal transition from RUNNING to RUNNING (#134)

[sh...@apache.org]

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shashikant pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-ratis.git


The following commit(s) were added to refs/heads/master by this push:
     new b2d367f  RATIS-982. Fix RaftServerImpl illegal transition from RUNNING to RUNNING (#134)
b2d367f is described below

commit b2d367fa9a9313c7bae3ca5a02c652a8804b97e1
Author: runzhiwang <51...@users.noreply.github.com>
AuthorDate: Wed Jun 24 16:29:29 2020 +0800

    RATIS-982. Fix RaftServerImpl illegal transition from RUNNING to RUNNING (#134)
---
 .../org/apache/ratis/server/impl/RaftServerImpl.java  | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java b/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java
index c5d5b48..c4f9ec2 100644
--- a/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java
+++ b/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java
@@ -48,6 +48,7 @@ import java.util.concurrent.CompletionException;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -94,6 +95,13 @@ public class RaftServerImpl implements RaftServerProtocol, RaftServerAsynchronou
 
   private AtomicReference<TermIndex> inProgressInstallSnapshotRequest;
 
+  // To avoid append entry before complete start() method
+  // For example, if thread1 start(), but before thread1 startAsFollower(), thread2 receive append entry
+  // request, and change state to RUNNING by lifeCycle.compareAndTransition(STARTING, RUNNING),
+  // then thread1 execute lifeCycle.transition(RUNNING) in startAsFollower(),
+  // So happens IllegalStateException: ILLEGAL TRANSITION: RUNNING -> RUNNING,
+  private AtomicBoolean startComplete;
+
   RaftServerImpl(RaftGroup group, StateMachine stateMachine, RaftServerProxy proxy) throws IOException {
     final RaftPeerId id = proxy.getId();
     LOG.info("{}: new RaftServerImpl for {} with {}", id, group, stateMachine);
@@ -118,6 +126,8 @@ public class RaftServerImpl implements RaftServerProtocol, RaftServerAsynchronou
     this.jmxAdapter = new RaftServerJmxAdapter();
     this.leaderElectionMetrics = LeaderElectionMetrics.getLeaderElectionMetrics(this);
     this.raftServerMetrics = RaftServerMetrics.getRaftServerMetrics(this);
+
+    this.startComplete = new AtomicBoolean(false);
   }
 
   private RetryCache initRetryCache(RaftProperties prop) {
@@ -192,6 +202,7 @@ public class RaftServerImpl implements RaftServerProtocol, RaftServerAsynchronou
 
     registerMBean(getId(), getMemberId().getGroupId(), jmxAdapter, jmxAdapter);
     state.start();
+    startComplete.compareAndSet(false, true);
     return true;
   }
 
@@ -946,11 +957,9 @@ public class RaftServerImpl implements RaftServerProtocol, RaftServerAsynchronou
     CodeInjectionForTesting.execute(APPEND_ENTRIES, getId(),
         leaderId, leaderTerm, previous, leaderCommit, initializing, entries);
 
-    final LifeCycle.State currentState = assertLifeCycleState(LifeCycle.States.STARTING_OR_RUNNING);
-    if (currentState == STARTING) {
-      if (role.getCurrentRole() == null) {
-        throw new ServerNotReadyException(getMemberId() + ": The server role is not yet initialized.");
-      }
+    assertLifeCycleState(LifeCycle.States.STARTING_OR_RUNNING);
+    if (!startComplete.get()) {
+      throw new ServerNotReadyException(getMemberId() + ": The server role is not yet initialized.");
     }
     assertGroup(leaderId, leaderGroupId);