[
https://issues.apache.org/jira/browse/CURATOR-549?focusedWorklogId=411718&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-411718
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ASF GitHub Bot logged work on CURATOR-549:
------------------------------------------
Author: ASF GitHub Bot
Created on: 28/Mar/20 13:55
Start Date: 28/Mar/20 13:55
Worklog Time Spent: 10m
Work Description: Randgalt commented on pull request #335: [CURATOR-549]
Recipes based on Persistent Recursive Watchers
URL: https://github.com/apache/curator/pull/335#discussion_r399665185
##########
File path:
curator-recipes/src/main/java/org/apache/curator/framework/recipes/cache/CuratorCacheImpl.java
##########
@@ -0,0 +1,301 @@
+/**
+ * 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.cache;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Sets;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.api.BackgroundCallback;
+import org.apache.curator.framework.api.CuratorEvent;
+import org.apache.curator.framework.listen.Listenable;
+import org.apache.curator.framework.listen.StandardListenerManager;
+import org.apache.curator.framework.recipes.watch.PersistentWatcher;
+import org.apache.curator.utils.ThreadUtils;
+import org.apache.curator.utils.ZKPaths;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.WatchedEvent;
+import org.apache.zookeeper.data.Stat;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.util.Collections;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+
+import static
org.apache.curator.framework.recipes.cache.CuratorCacheListener.Type.*;
+import static org.apache.zookeeper.KeeperException.Code.NONODE;
+import static org.apache.zookeeper.KeeperException.Code.OK;
+
+class CuratorCacheImpl implements CuratorCache
+{
+ private final Logger log = LoggerFactory.getLogger(getClass());
+ private final AtomicReference<State> state = new
AtomicReference<>(State.LATENT);
+ private final PersistentWatcher persistentWatcher;
+ private final CuratorFramework client;
+ private final CuratorCacheStorage storage;
+ private final String path;
+ private final boolean recursive;
+ private final boolean compressedData;
+ private final boolean clearOnClose;
+ private final StandardListenerManager<CuratorCacheListener>
listenerManager = StandardListenerManager.standard();
+ private final Consumer<Exception> exceptionHandler;
+ private final OutstandingOps outstandingOps = new OutstandingOps(() ->
callListeners(CuratorCacheListener::initialized));
+
+ private enum State
+ {
+ LATENT,
+ STARTED,
+ CLOSED
+ }
+
+ CuratorCacheImpl(CuratorFramework client, CuratorCacheStorage storage,
String path, Options[] optionsArg, Consumer<Exception> exceptionHandler)
+ {
+ Set<Options> options = (optionsArg != null) ?
Sets.newHashSet(optionsArg) : Collections.emptySet();
+ this.client = client;
+ this.storage = (storage != null) ? storage :
CuratorCacheStorage.standard();
+ this.path = path;
+ recursive = !options.contains(Options.SINGLE_NODE_CACHE);
+ compressedData = options.contains(Options.COMPRESSED_DATA);
+ clearOnClose = !options.contains(Options.DO_NOT_CLEAR_ON_CLOSE);
+ persistentWatcher = new PersistentWatcher(client, path, recursive);
+ persistentWatcher.getListenable().addListener(this::processEvent);
+ persistentWatcher.getResetListenable().addListener(this::rebuild);
+ this.exceptionHandler = (exceptionHandler != null) ? exceptionHandler
: e -> log.error("CuratorCache error", e);
+ }
+
+ @Override
+ public void start()
+ {
+ Preconditions.checkState(state.compareAndSet(State.LATENT,
State.STARTED), "Already started");
+ persistentWatcher.start();
+ }
+
+ @Override
+ public void close()
+ {
+ if ( state.compareAndSet(State.STARTED, State.CLOSED) )
+ {
+ persistentWatcher.close();
+ if ( clearOnClose )
+ {
+ storage.clear();
+ }
+ }
+ }
+
+ @Override
+ public Listenable<CuratorCacheListener> listenable()
+ {
+ return listenerManager;
+ }
+
+ @Override
+ public Optional<ChildData> get(String path)
+ {
+ return storage.get(path);
+ }
+
+ @Override
+ public int size()
+ {
+ return storage.size();
+ }
+
+ @Override
+ public Stream<ChildData> stream()
+ {
+ return storage.stream();
+ }
+
+ @VisibleForTesting
+ CuratorCacheStorage storage()
+ {
+ return storage;
+ }
+
+ private void rebuild()
+ {
+ if ( state.get() != State.STARTED )
+ {
+ return;
+ }
+
+ // rebuild from the root first
+ nodeChanged(path);
+
+ // rebuild remaining nodes - note: this may cause some nodes to be
queried twice
+ // (though versions checks will minimize that). If someone can think
of a better
+ // way let us know
+ storage.stream()
+ .map(ChildData::getPath)
+ .filter(p -> !p.equals(path))
+ .forEach(this::nodeChanged);
+ }
+
+ private void processEvent(WatchedEvent event)
+ {
+ if ( state.get() != State.STARTED )
+ {
+ return;
+ }
+
+ // NOTE: Persistent/Recursive watchers never trigger
NodeChildrenChanged
+
+ switch ( event.getType() )
+ {
+ case NodeDataChanged:
+ case NodeCreated:
+ {
+ nodeChanged(event.getPath());
+ break;
+ }
+
+ case NodeDeleted:
+ {
+ removeStorage(event.getPath());
+ break;
+ }
+ }
+ }
+
+ private void checkChildrenChanged(String fromPath, Stat oldStat, Stat
newStat)
+ {
+ if ( (state.get() != State.STARTED) || !recursive )
+ {
+ return;
+ }
+
+ if ( (oldStat != null) && (oldStat.getCversion() ==
newStat.getCversion()) )
+ {
+ return; // children haven't changed
+ }
+
+ try
+ {
+ BackgroundCallback callback = (__, event) -> {
+ if ( event.getResultCode() == OK.intValue() )
+ {
+ event.getChildren().forEach(child ->
nodeChanged(ZKPaths.makePath(fromPath, child)));
+ }
+ else if ( event.getResultCode() == NONODE.intValue() )
+ {
+ removeStorage(event.getPath());
+ }
+ else
+ {
+ handleException(event);
+ }
+ outstandingOps.decrement();
+ };
+
+ outstandingOps.increment();
+ client.getChildren().inBackground(callback).forPath(fromPath);
+ }
+ catch ( Exception e )
+ {
+ handleException(e);
+ }
+ }
+
+ private void nodeChanged(String fromPath)
+ {
+ if ( state.get() != State.STARTED )
+ {
+ return;
+ }
+
+ try
+ {
+ BackgroundCallback callback = (__, event) -> {
+ if ( event.getResultCode() == OK.intValue() )
+ {
+ Optional<ChildData> childData = putStorage(new
ChildData(event.getPath(), event.getStat(), event.getData()));
+ checkChildrenChanged(event.getPath(),
childData.map(ChildData::getStat).orElse(null), event.getStat());
+ }
+ else if ( event.getResultCode() == NONODE.intValue() )
+ {
+ removeStorage(event.getPath());
+ }
+ else
+ {
+ handleException(event);
+ }
+ outstandingOps.decrement();
+ };
+
+ outstandingOps.increment();
+ if ( compressedData )
+ {
+
client.getData().decompressed().inBackground(callback).forPath(fromPath);
+ }
+ else
+ {
+ client.getData().inBackground(callback).forPath(fromPath);
+ }
+ }
+ catch ( Exception e )
+ {
+ handleException(e);
+ }
+ }
+
+ private Optional<ChildData> putStorage(ChildData data)
+ {
+ Optional<ChildData> previousData = storage.put(data);
+ if ( previousData.isPresent() )
+ {
+ if ( previousData.get().getStat().getVersion() !=
data.getStat().getVersion() )
+ {
+ callListeners(l -> l.event(NODE_CHANGED, previousData.get(),
data));
+ }
+ }
+ else
+ {
+ callListeners(l -> l.event(NODE_CREATED, null, data));
+ }
+ return previousData;
+ }
+
+ private void removeStorage(String path)
+ {
+ storage.remove(path).ifPresent(previousData -> callListeners(l ->
l.event(NODE_DELETED, previousData, null)));
+ }
+
+ private void callListeners(Consumer<CuratorCacheListener> proc)
+ {
+ if ( state.get() == State.STARTED )
+ {
+ client.runSafe(() -> listenerManager.forEach(proc));
+ }
+ }
+
+ private void handleException(CuratorEvent event)
+ {
+
handleException(KeeperException.create(KeeperException.Code.get(event.getResultCode())));
+ }
+
+ private void handleException(Exception e)
+ {
+ ThreadUtils.checkInterrupted(e);
Review comment:
It's important to reset the interrupted flag. I don't think we should count
on the end user doing that. Curator has had this behavior for a long time.
Maybe we can re-visit it in another issue.
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Issue Time Tracking
-------------------
Worklog Id: (was: 411718)
Time Spent: 14h 10m (was: 14h)
> ZooKeeper 3.6 will add support for Persistent Recursive Watchers - Add
> Curator support
> --------------------------------------------------------------------------------------
>
> Key: CURATOR-549
> URL: https://issues.apache.org/jira/browse/CURATOR-549
> Project: Apache Curator
> Issue Type: Improvement
> Components: Client, Documentation, Framework, Recipes, Tests
> Affects Versions: 4.2.0
> Reporter: Jordan Zimmerman
> Assignee: Jordan Zimmerman
> Priority: Major
> Fix For: 5.0.0
>
> Time Spent: 14h 10m
> Remaining Estimate: 0h
>
> ZOOKEEPER-1416 will add support for Persistent Recursive Watchers. This
> feature allows Curator to re-think/re-write the various cache recipes so that
> they're simpler, use less resources and more stable.
> * Change Curator to depend on ZooKeeper 3.6.x
> * Add a new module so that backward compatibility with 3.5 is ensured
> * Add new methods corresponding to {{ZooKeeper.addWatch()}}
> * Add a new recipe that enables a fully managed Persistent watch
> * Create new Cache recipes that use the new Persistent watch recipe
> * Replace internal usages of TreeCache/PathChildrenCache/NodeCache with new
> cache recipe
> * Deprecate TreeCache/PathChildrenCache/NodeCache
> * Updated docs/tests/etc
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