You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@curator.apache.org by ra...@apache.org on 2019/10/03 16:16:52 UTC
[curator] 02/02: Added support for a PersistentWatcher recipe based
on new persistent watch APIs
This is an automated email from the ASF dual-hosted git repository.
randgalt pushed a commit to branch persistent-watcher-recipe
in repository https://gitbox.apache.org/repos/asf/curator.git
commit 55938084e46950578b2466b7dfe689dd2a77d3c4
Author: randgalt <ra...@apache.org>
AuthorDate: Wed Oct 2 23:24:14 2019 -0500
Added support for a PersistentWatcher recipe based on new persistent watch APIs
---
.../imps/AddPersistentWatchBuilderImpl.java | 169 ---------------------
.../framework/recipes/watch/PersistentWatcher.java | 134 ++++++++++++++++
.../recipes/watch/TestPersistentWatcher.java | 86 +++++++++++
3 files changed, 220 insertions(+), 169 deletions(-)
diff --git a/curator-framework/src/main/java/org/apache/curator/framework/imps/AddPersistentWatchBuilderImpl.java b/curator-framework/src/main/java/org/apache/curator/framework/imps/AddPersistentWatchBuilderImpl.java
deleted file mode 100644
index acb70c8..0000000
--- a/curator-framework/src/main/java/org/apache/curator/framework/imps/AddPersistentWatchBuilderImpl.java
+++ /dev/null
@@ -1,169 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied. See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-package org.apache.curator.framework.imps;
-
-import org.apache.curator.RetryLoop;
-import org.apache.curator.drivers.OperationTrace;
-import org.apache.curator.framework.api.AddPersistentWatchBuilder;
-import org.apache.curator.framework.api.AddPersistentWatchBuilder2;
-import org.apache.curator.framework.api.AddPersistentWatchable;
-import org.apache.curator.framework.api.BackgroundCallback;
-import org.apache.curator.framework.api.CuratorEvent;
-import org.apache.curator.framework.api.CuratorEventType;
-import org.apache.curator.framework.api.CuratorWatcher;
-import org.apache.curator.framework.api.Pathable;
-import org.apache.zookeeper.Watcher;
-import java.util.concurrent.Executor;
-
-public class AddPersistentWatchBuilderImpl implements AddPersistentWatchBuilder, Pathable<Void>, BackgroundOperation<String>
-{
- private final CuratorFrameworkImpl client;
- private Watching watching = null;
- private Backgrounding backgrounding = new Backgrounding();
- private boolean recursive = false;
-
- AddPersistentWatchBuilderImpl(CuratorFrameworkImpl client)
- {
- this.client = client;
- }
-
- public AddPersistentWatchBuilderImpl(CuratorFrameworkImpl client, Watching watching, Backgrounding backgrounding, boolean recursive)
- {
- this.client = client;
- this.watching = watching;
- this.backgrounding = backgrounding;
- this.recursive = recursive;
- }
-
- @Override
- public AddPersistentWatchable<Pathable<Void>> inBackground()
- {
- backgrounding = new Backgrounding();
- return this;
- }
-
- @Override
- public AddPersistentWatchBuilder2 recursive()
- {
- recursive = true;
- return this;
- }
-
- @Override
- public Pathable<Void> usingWatcher(Watcher watcher)
- {
- watching = new Watching(client, watcher);
- return this;
- }
-
- @Override
- public Pathable<Void> usingWatcher(CuratorWatcher watcher)
- {
- watching = new Watching(client, watcher);
- return this;
- }
-
- @Override
- public AddPersistentWatchable<Pathable<Void>> inBackground(Object context)
- {
- backgrounding = new Backgrounding(context);
- return this;
- }
-
- @Override
- public AddPersistentWatchable<Pathable<Void>> inBackground(BackgroundCallback callback)
- {
- backgrounding = new Backgrounding(callback);
- return this;
- }
-
- @Override
- public AddPersistentWatchable<Pathable<Void>> inBackground(BackgroundCallback callback, Object context)
- {
- backgrounding = new Backgrounding(callback, context);
- return this;
- }
-
- @Override
- public AddPersistentWatchable<Pathable<Void>> inBackground(BackgroundCallback callback, Executor executor)
- {
- backgrounding = new Backgrounding(callback, executor);
- return this;
- }
-
- @Override
- public AddPersistentWatchable<Pathable<Void>> inBackground(BackgroundCallback callback, Object context, Executor executor)
- {
- backgrounding = new Backgrounding(client, callback, context, executor);
- return this;
- }
-
- @Override
- public Void forPath(String path) throws Exception
- {
- if ( backgrounding.inBackground() )
- {
- client.processBackgroundOperation(new OperationAndData<>(this, path, backgrounding.getCallback(), null, backgrounding.getContext(), watching), null);
- }
- else
- {
- pathInForeground(path);
- }
- return null;
- }
-
- @Override
- public void performBackgroundOperation(final OperationAndData<String> data) throws Exception
- {
- String path = data.getData();
- String fixedPath = client.fixForNamespace(path);
- try
- {
- final OperationTrace trace = client.getZookeeperClient().startAdvancedTracer("AddPersistentWatchBuilderImpl-Background");
- client.getZooKeeper().addPersistentWatch
- (
- fixedPath,
- watching.getWatcher(path),
- recursive, (rc, path1, ctx) -> {
- trace.setReturnCode(rc).setWithWatcher(true).setPath(path1).commit();
- CuratorEvent event = new CuratorEventImpl(client, CuratorEventType.ADD_PERSISTENT_WATCH, rc, path1, null, ctx, null, null, null, null, null, null);
- client.processBackgroundOperation(data, event);
- },
- backgrounding.getContext()
- );
- }
- catch ( Throwable e )
- {
- backgrounding.checkError(e, watching);
- }
- }
-
- private void pathInForeground(final String path) throws Exception
- {
- final String fixedPath = client.fixForNamespace(path);
- OperationTrace trace = client.getZookeeperClient().startAdvancedTracer("AddPersistentWatchBuilderImpl-Foreground");
- RetryLoop.callWithRetry
- (
- client.getZookeeperClient(), () -> {
- client.getZooKeeper().addPersistentWatch(fixedPath, watching.getWatcher(path), recursive);
- return null;
- });
- trace.setPath(fixedPath).setWithWatcher(true).commit();
- }
-}
\ No newline at end of file
diff --git a/curator-recipes/src/main/java/org/apache/curator/framework/recipes/watch/PersistentWatcher.java b/curator-recipes/src/main/java/org/apache/curator/framework/recipes/watch/PersistentWatcher.java
new file mode 100644
index 0000000..2c97490
--- /dev/null
+++ b/curator-recipes/src/main/java/org/apache/curator/framework/recipes/watch/PersistentWatcher.java
@@ -0,0 +1,134 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+ package org.apache.curator.framework.recipes.watch;
+
+import com.google.common.base.Preconditions;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.api.BackgroundCallback;
+import org.apache.curator.framework.listen.Listenable;
+import org.apache.curator.framework.listen.StandardListenerManager;
+import org.apache.curator.framework.state.ConnectionStateListener;
+import org.apache.curator.utils.ThreadUtils;
+import org.apache.zookeeper.AddWatchMode;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.Watcher;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.io.Closeable;
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * A managed persistent watcher. The watch will be managed such that it stays set through
+ * connection lapses, etc.
+ */
+ public class PersistentWatcher implements Closeable
+ {
+ private final Logger log = LoggerFactory.getLogger(getClass());
+ private final AtomicReference<State> state = new AtomicReference<>(State.LATENT);
+ private final StandardListenerManager<Watcher> listeners = StandardListenerManager.standard();
+ private final ConnectionStateListener connectionStateListener = (client, newState) -> {
+ if ( newState.isConnected() )
+ {
+ reset();
+ }
+ };
+ private final Watcher watcher = event -> listeners.forEach(w -> w.process(event));
+ private final CuratorFramework client;
+ private final String basePath;
+ private final boolean recursive;
+
+ private enum State
+ {
+ LATENT,
+ STARTED,
+ CLOSED
+ }
+
+ /**
+ * @param client client
+ * @param basePath path to set the watch on
+ * @param recursive ZooKeeper persistent watches can optionally be recursive
+ */
+ public PersistentWatcher(CuratorFramework client, String basePath, boolean recursive)
+ {
+ this.client = Objects.requireNonNull(client, "client cannot be null");
+ this.basePath = Objects.requireNonNull(basePath, "basePath cannot be null");
+ this.recursive = recursive;
+ }
+
+ /**
+ * Start watching
+ */
+ public void start()
+ {
+ Preconditions.checkState(state.compareAndSet(State.LATENT, State.STARTED), "Already started");
+ client.getConnectionStateListenable().addListener(connectionStateListener);
+ reset();
+ }
+
+ /**
+ * Remove the watcher
+ */
+ @Override
+ public void close()
+ {
+ if ( state.compareAndSet(State.STARTED, State.CLOSED) )
+ {
+ listeners.clear();
+ client.getConnectionStateListenable().removeListener(connectionStateListener);
+ try
+ {
+ client.watches().remove(watcher).guaranteed().inBackground().forPath(basePath);
+ }
+ catch ( Exception e )
+ {
+ ThreadUtils.checkInterrupted(e);
+ log.debug(String.format("Could not remove watcher for path: %s", basePath), e);
+ }
+ }
+ }
+
+ /**
+ * Container for setting listeners
+ *
+ * @return listener container
+ */
+ public Listenable<Watcher> getListenable()
+ {
+ return listeners;
+ }
+
+ private void reset()
+ {
+ try
+ {
+ BackgroundCallback callback = (__, event) -> {
+ if ( event.getResultCode() != KeeperException.Code.OK.intValue() ) {
+ client.runSafe(this::reset);
+ }
+ };
+ client.addWatch().withMode(recursive ? AddWatchMode.PERSISTENT_RECURSIVE : AddWatchMode.PERSISTENT).inBackground(callback).usingWatcher(watcher).forPath(basePath);
+ }
+ catch ( Exception e )
+ {
+ log.error("Could not reset persistent watch at path: " + basePath, e);
+ }
+ }
+ }
\ No newline at end of file
diff --git a/curator-recipes/src/test/java/org/apache/curator/framework/recipes/watch/TestPersistentWatcher.java b/curator-recipes/src/test/java/org/apache/curator/framework/recipes/watch/TestPersistentWatcher.java
new file mode 100644
index 0000000..df18de5
--- /dev/null
+++ b/curator-recipes/src/test/java/org/apache/curator/framework/recipes/watch/TestPersistentWatcher.java
@@ -0,0 +1,86 @@
+package org.apache.curator.framework.recipes.watch;
+
+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.compatibility.Timing2;
+import org.apache.zookeeper.WatchedEvent;
+import org.apache.zookeeper.Watcher;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.LinkedBlockingQueue;
+
+public class TestPersistentWatcher extends BaseClassForTests
+{
+ private final Timing2 timing = new Timing2();
+
+ @Test
+ public void testConnectionLostRecursive() throws Exception
+ {
+ internalTest(true);
+ }
+
+ @Test
+ public void testConnectionLost() throws Exception
+ {
+ internalTest(false);
+ }
+
+ private void internalTest(boolean recursive) throws Exception
+ {
+ try ( CuratorFramework client = CuratorFrameworkFactory.newClient(server.getConnectString(), timing.session(), timing.connection(), new RetryOneTime(1)) )
+ {
+ CountDownLatch lostLatch = new CountDownLatch(1);
+ CountDownLatch reconnectedLatch = new CountDownLatch(1);
+ client.start();
+ client.getConnectionStateListenable().addListener((__, newState) -> {
+ if ( newState == ConnectionState.LOST ) {
+ lostLatch.countDown();
+ } else if ( newState == ConnectionState.RECONNECTED ) {
+ reconnectedLatch.countDown();
+ }
+ });
+
+ try ( PersistentWatcher persistentWatcher = new PersistentWatcher(client, "/top/main", recursive) )
+ {
+ persistentWatcher.start();
+
+ BlockingQueue<WatchedEvent> events = new LinkedBlockingQueue<>();
+ persistentWatcher.getListenable().addListener(events::add);
+
+ client.create().creatingParentsIfNeeded().forPath("/top/main/a");
+ Assert.assertEquals(timing.takeFromQueue(events).getPath(), "/top/main");
+ if ( recursive )
+ {
+ Assert.assertEquals(timing.takeFromQueue(events).getPath(), "/top/main/a");
+ }
+ else
+ {
+ Assert.assertEquals(timing.takeFromQueue(events).getPath(), "/top/main"); // child added
+ }
+
+ server.stop();
+ Assert.assertEquals(timing.takeFromQueue(events).getState(), Watcher.Event.KeeperState.Disconnected);
+ Assert.assertTrue(timing.awaitLatch(lostLatch));
+
+ server.restart();
+ Assert.assertTrue(timing.awaitLatch(reconnectedLatch));
+
+ timing.sleepABit(); // time to allow watcher to get reset
+ events.clear();
+
+ if ( recursive )
+ {
+ client.setData().forPath("/top/main/a", "foo".getBytes());
+ Assert.assertEquals(timing.takeFromQueue(events).getType(), Watcher.Event.EventType.NodeDataChanged);
+ }
+ client.setData().forPath("/top/main", "bar".getBytes());
+ Assert.assertEquals(timing.takeFromQueue(events).getPath(), "/top/main");
+ }
+ }
+ }
+}