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Posted to commits@curator.apache.org by ra...@apache.org on 2018/06/24 14:08:42 UTC
curator git commit: Fix for CURATOR-452
Repository: curator
Updated Branches:
refs/heads/CURATOR-452 [created] cc30b67c8
Fix for CURATOR-452
race in ServiceCacheImpl's start() method caused by an optimization whereby it clears the dataBytes of its internal PathChildrenCache - was causing an intermittent NPE
Project: http://git-wip-us.apache.org/repos/asf/curator/repo
Commit: http://git-wip-us.apache.org/repos/asf/curator/commit/cc30b67c
Tree: http://git-wip-us.apache.org/repos/asf/curator/tree/cc30b67c
Diff: http://git-wip-us.apache.org/repos/asf/curator/diff/cc30b67c
Branch: refs/heads/CURATOR-452
Commit: cc30b67c8dbe24babd31ed654e9536fe776b8a18
Parents: a1f620e
Author: randgalt <ra...@apache.org>
Authored: Sun Jun 24 09:08:02 2018 -0500
Committer: randgalt <ra...@apache.org>
Committed: Sun Jun 24 09:08:02 2018 -0500
----------------------------------------------------------------------
.../x/discovery/details/ServiceCacheImpl.java | 22 +++-
.../discovery/details/TestServiceCacheRace.java | 110 +++++++++++++++++++
2 files changed, 131 insertions(+), 1 deletion(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/curator/blob/cc30b67c/curator-x-discovery/src/main/java/org/apache/curator/x/discovery/details/ServiceCacheImpl.java
----------------------------------------------------------------------
diff --git a/curator-x-discovery/src/main/java/org/apache/curator/x/discovery/details/ServiceCacheImpl.java b/curator-x-discovery/src/main/java/org/apache/curator/x/discovery/details/ServiceCacheImpl.java
index b8f39d5..d1a31ad 100644
--- a/curator-x-discovery/src/main/java/org/apache/curator/x/discovery/details/ServiceCacheImpl.java
+++ b/curator-x-discovery/src/main/java/org/apache/curator/x/discovery/details/ServiceCacheImpl.java
@@ -18,6 +18,7 @@
*/
package org.apache.curator.x.discovery.details;
+import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
@@ -36,6 +37,7 @@ import org.apache.curator.x.discovery.ServiceInstance;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
@@ -85,15 +87,33 @@ public class ServiceCacheImpl<T> implements ServiceCache<T>, PathChildrenCacheLi
return Lists.newArrayList(instances.values());
}
+ @VisibleForTesting
+ volatile CountDownLatch debugStartLatch = null;
+ volatile CountDownLatch debugStartWaitLatch = null;
+
@Override
public void start() throws Exception
{
Preconditions.checkState(state.compareAndSet(State.LATENT, State.STARTED), "Cannot be started more than once");
cache.start(true);
+ if ( debugStartLatch != null )
+ {
+ debugStartLatch.countDown();
+ debugStartLatch = null;
+ }
+ if ( debugStartWaitLatch != null )
+ {
+ debugStartWaitLatch.await();
+ debugStartWaitLatch = null;
+ }
+
for ( ChildData childData : cache.getCurrentData() )
{
- addInstance(childData, true);
+ if ( childData.getData() != null ) // else already processed by the cache listener
+ {
+ addInstance(childData, true);
+ }
}
discovery.cacheOpened(this);
}
http://git-wip-us.apache.org/repos/asf/curator/blob/cc30b67c/curator-x-discovery/src/test/java/org/apache/curator/x/discovery/details/TestServiceCacheRace.java
----------------------------------------------------------------------
diff --git a/curator-x-discovery/src/test/java/org/apache/curator/x/discovery/details/TestServiceCacheRace.java b/curator-x-discovery/src/test/java/org/apache/curator/x/discovery/details/TestServiceCacheRace.java
new file mode 100644
index 0000000..08a2a8e
--- /dev/null
+++ b/curator-x-discovery/src/test/java/org/apache/curator/x/discovery/details/TestServiceCacheRace.java
@@ -0,0 +1,110 @@
+package org.apache.curator.x.discovery.details;
+
+import com.google.common.collect.Lists;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.CuratorFrameworkFactory;
+import org.apache.curator.framework.state.ConnectionState;
+import org.apache.curator.retry.RetryOneTime;
+import org.apache.curator.test.BaseClassForTests;
+import org.apache.curator.test.Timing;
+import org.apache.curator.utils.CloseableExecutorService;
+import org.apache.curator.utils.CloseableUtils;
+import org.apache.curator.x.discovery.ServiceCache;
+import org.apache.curator.x.discovery.ServiceDiscovery;
+import org.apache.curator.x.discovery.ServiceDiscoveryBuilder;
+import org.apache.curator.x.discovery.ServiceInstance;
+import org.slf4j.LoggerFactory;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+import java.io.Closeable;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executors;
+
+public class TestServiceCacheRace extends BaseClassForTests
+{
+ private final Timing timing = new Timing();
+
+ // validates CURATOR-452 which exposed a race in ServiceCacheImpl's start() method caused by an optimization whereby it clears the dataBytes of its internal PathChildrenCache
+ @Test
+ public void testRaceOnInitialLoad() throws Exception
+ {
+ List<Closeable> closeables = Lists.newArrayList();
+ try
+ {
+ CuratorFramework client = CuratorFrameworkFactory.newClient(server.getConnectString(), new RetryOneTime(1));
+ closeables.add(client);
+ client.start();
+
+ ServiceDiscovery<String> discovery = ServiceDiscoveryBuilder.builder(String.class).basePath("/discovery").client(client).build();
+ closeables.add(discovery);
+ discovery.start();
+
+ CountDownLatch cacheStartLatch = new CountDownLatch(1);
+ CountDownLatch cacheWaitLatch = new CountDownLatch(1);
+ final ServiceCache<String> cache = discovery.serviceCacheBuilder().name("test").build();
+ closeables.add(cache);
+ ((ServiceCacheImpl)cache).debugStartLatch = cacheStartLatch; // causes ServiceCacheImpl.start to notify just after starting its internal PathChildrenCache
+ ((ServiceCacheImpl)cache).debugStartWaitLatch = cacheWaitLatch; // causes ServiceCacheImpl.start to wait before iterating over its internal PathChildrenCache
+
+ ServiceInstance<String> instance1 = ServiceInstance.<String>builder().payload("test").name("test").port(10064).build();
+ discovery.registerService(instance1);
+
+ CloseableExecutorService closeableExecutorService = new CloseableExecutorService(Executors.newSingleThreadExecutor());
+ closeables.add(closeableExecutorService);
+ final CountDownLatch startCompletedLatch = new CountDownLatch(1);
+ Runnable proc = new Runnable()
+ {
+ @Override
+ public void run()
+ {
+ try
+ {
+ cache.start();
+ startCompletedLatch.countDown();
+ }
+ catch ( Exception e )
+ {
+ LoggerFactory.getLogger(getClass()).error("Start failed", e);
+ throw new RuntimeException(e);
+ }
+ }
+ };
+ closeableExecutorService.submit(proc);
+ Assert.assertTrue(timing.awaitLatch(cacheStartLatch)); // wait until ServiceCacheImpl's internal PathChildrenCache is started and primed
+
+ final CountDownLatch cacheChangedLatch = new CountDownLatch(1);
+ ServiceCacheListener listener = new ServiceCacheListener()
+ {
+ @Override
+ public void cacheChanged()
+ {
+ cacheChangedLatch.countDown();
+ }
+
+ @Override
+ public void stateChanged(CuratorFramework client, ConnectionState newState)
+ {
+ // NOP
+ }
+ };
+ cache.addListener(listener);
+ ServiceInstance<String> instance2 = ServiceInstance.<String>builder().payload("test").name("test").port(10065).build();
+ discovery.registerService(instance2); // cause ServiceCacheImpl's internal PathChildrenCache listener to get called which will clear the dataBytes
+ Assert.assertTrue(timing.awaitLatch(cacheChangedLatch));
+
+ cacheWaitLatch.countDown();
+
+ Assert.assertTrue(timing.awaitLatch(startCompletedLatch));
+ }
+ finally
+ {
+ Collections.reverse(closeables);
+ for ( Closeable c : closeables )
+ {
+ CloseableUtils.closeQuietly(c);
+ }
+ }
+ }
+}