[GitHub] [sling-org-apache-sling-distribution-journal] tmaret commented on a change in pull request #99: SLING-10077: Mode to raise events only locally

[GitBox <gi...@apache.org>]

tmaret commented on a change in pull request #99:
URL: https://github.com/apache/sling-org-apache-sling-distribution-journal/pull/99#discussion_r811812613



##########
File path: src/main/java/org/apache/sling/distribution/journal/impl/publisher/DistributedEventNotifierManager.java
##########
@@ -0,0 +1,142 @@
+/*
+ * 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.sling.distribution.journal.impl.publisher;
+
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.Map;
+
+import org.apache.sling.api.resource.ResourceResolverFactory;
+import org.apache.sling.discovery.TopologyEvent;
+import org.apache.sling.discovery.TopologyEventListener;
+import org.apache.sling.distribution.journal.MessagingProvider;
+import org.apache.sling.distribution.journal.bookkeeper.LocalStore;
+import org.apache.sling.distribution.journal.impl.discovery.TopologyChangeHandler;
+import org.apache.sling.distribution.journal.queue.PubQueueProvider;
+import org.apache.sling.distribution.journal.shared.Topics;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.ServiceRegistration;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.event.EventAdmin;
+import org.osgi.service.metatype.annotations.AttributeDefinition;
+import org.osgi.service.metatype.annotations.Designate;
+import org.osgi.service.metatype.annotations.ObjectClassDefinition;
+
+import static org.apache.sling.discovery.TopologyEvent.Type;
+import static org.apache.sling.discovery.TopologyEvent.Type.TOPOLOGY_CHANGED;
+import static org.apache.sling.discovery.TopologyEvent.Type.TOPOLOGY_CHANGING;
+import static org.apache.sling.discovery.TopologyEvent.Type.TOPOLOGY_INIT;
+
+@Component(immediate = true, service = TopologyEventListener.class)
+@Designate(ocd = DistributedEventNotifierManager.Configuration.class)
+public class DistributedEventNotifierManager implements TopologyEventListener {
+
+    /*
+     * Register the package distributed event notifier service
+     * on all or only the leader instance in a cluster according
+     * to the configuration.
+     */
+
+    @Reference
+    private EventAdmin eventAdmin;
+
+    @Reference
+    private PubQueueProvider pubQueueCacheService;
+
+    @Reference
+    private MessagingProvider messagingProvider;
+
+    @Reference
+    private Topics topics;
+
+    @Reference
+    private ResourceResolverFactory resolverFactory;
+
+    private ServiceRegistration<TopologyChangeHandler> reg;
+
+    private BundleContext context;
+
+    private Configuration config;
+
+    private Map<String, LocalStore> localStores;
+
+    private boolean isLeader;
+
+    @Activate
+    public void activate(BundleContext context, Configuration config) {
+        this.context = context;
+        this.config = config;
+        this.localStores = new HashMap<>();
+        if (! config.deduplicateEvent()) {
+            registerService();
+        }
+    }
+
+    public void deactivate() {

Review comment:
       The method must be annotated with `@Deactivate` in order to be invoked by the OSGi framework.

##########
File path: src/main/java/org/apache/sling/distribution/journal/impl/publisher/DistributedEventNotifierManager.java
##########
@@ -0,0 +1,142 @@
+/*
+ * 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.sling.distribution.journal.impl.publisher;
+
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.Map;
+
+import org.apache.sling.api.resource.ResourceResolverFactory;
+import org.apache.sling.discovery.TopologyEvent;
+import org.apache.sling.discovery.TopologyEventListener;
+import org.apache.sling.distribution.journal.MessagingProvider;
+import org.apache.sling.distribution.journal.bookkeeper.LocalStore;
+import org.apache.sling.distribution.journal.impl.discovery.TopologyChangeHandler;
+import org.apache.sling.distribution.journal.queue.PubQueueProvider;
+import org.apache.sling.distribution.journal.shared.Topics;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.ServiceRegistration;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.event.EventAdmin;
+import org.osgi.service.metatype.annotations.AttributeDefinition;
+import org.osgi.service.metatype.annotations.Designate;
+import org.osgi.service.metatype.annotations.ObjectClassDefinition;
+
+import static org.apache.sling.discovery.TopologyEvent.Type;
+import static org.apache.sling.discovery.TopologyEvent.Type.TOPOLOGY_CHANGED;
+import static org.apache.sling.discovery.TopologyEvent.Type.TOPOLOGY_CHANGING;
+import static org.apache.sling.discovery.TopologyEvent.Type.TOPOLOGY_INIT;
+
+@Component(immediate = true, service = TopologyEventListener.class)
+@Designate(ocd = DistributedEventNotifierManager.Configuration.class)
+public class DistributedEventNotifierManager implements TopologyEventListener {
+
+    /*
+     * Register the package distributed event notifier service
+     * on all or only the leader instance in a cluster according
+     * to the configuration.
+     */
+
+    @Reference
+    private EventAdmin eventAdmin;
+
+    @Reference
+    private PubQueueProvider pubQueueCacheService;
+
+    @Reference
+    private MessagingProvider messagingProvider;
+
+    @Reference
+    private Topics topics;
+
+    @Reference
+    private ResourceResolverFactory resolverFactory;
+
+    private ServiceRegistration<TopologyChangeHandler> reg;
+
+    private BundleContext context;
+
+    private Configuration config;
+
+    private Map<String, LocalStore> localStores;

Review comment:
       The `localStores` field should be kept only in `PackageDistributedNotifier`. The field would be instantiated directly in `PackageDistributedNotifier` instead of being passed by reference through the constructor.

##########
File path: src/main/java/org/apache/sling/distribution/journal/impl/publisher/PackageDistributedNotifier.java
##########
@@ -34,49 +30,69 @@
 import org.apache.sling.distribution.journal.queue.PubQueueProvider;
 import org.apache.sling.distribution.journal.queue.QueueItemFactory;
 import org.apache.sling.distribution.journal.shared.Topics;
-import org.apache.sling.distribution.journal.MessagingProvider;
-
-import org.apache.commons.lang3.StringUtils;
 import org.apache.sling.distribution.queue.DistributionQueueItem;
-import org.osgi.service.component.annotations.Activate;
-import org.osgi.service.component.annotations.Component;
-import org.osgi.service.component.annotations.Reference;
 import org.osgi.service.event.Event;
 import org.osgi.service.event.EventAdmin;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import javax.annotation.ParametersAreNonnullByDefault;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
+import java.util.stream.LongStream;
+
+import static org.apache.sling.distribution.journal.impl.subscriber.DistributionSubscriber.escapeTopicName;
 import static org.apache.sling.distribution.packaging.DistributionPackageInfo.PROPERTY_REQUEST_DEEP_PATHS;
 import static org.apache.sling.distribution.packaging.DistributionPackageInfo.PROPERTY_REQUEST_PATHS;
 
-@Component(immediate = true)
 @ParametersAreNonnullByDefault
 public class PackageDistributedNotifier implements TopologyChangeHandler {
 
     private static final Logger LOG = LoggerFactory.getLogger(PackageDistributedNotifier.class);
 
-    @Reference
-    private EventAdmin eventAdmin;
+    public static final String STORE_TYPE_OFFSETS = "lastRaisedEventOffset";
+
+    private final Map<String, Long> lastDistributedOffsets = new HashMap<>();
 
-    @Reference
-    private PubQueueProvider pubQueueCacheService;
+    private final EventAdmin eventAdmin;
 
-    @Reference
-    private MessagingProvider messagingProvider;
+    private final PubQueueProvider pubQueueCacheService;
+
+    private  MessagingProvider messagingProvider;
 
-    @Reference
     private Topics topics;
 
+    private ResourceResolverFactory resolverFactory;
+
+    private Map<String, LocalStore> localStores;
+
     private Consumer<PackageDistributedMessage> sender;
 
-    private boolean sendMsg;
+    private final boolean sendMsg;
+
+    public PackageDistributedNotifier(EventAdmin eventAdmin, PubQueueProvider pubQueueCacheService, MessagingProvider messagingProvider, Topics topics, ResourceResolverFactory resolverFactory, Map<String, LocalStore> localStores) {
+        this.eventAdmin = eventAdmin;
+        this.pubQueueCacheService = pubQueueCacheService;
+        this.messagingProvider = messagingProvider;
+        this.topics = topics;
+        this.resolverFactory = resolverFactory;
+        this.localStores = localStores;
 
-    @Activate
-    public void activate() {
         sendMsg = StringUtils.isNotBlank(topics.getEventTopic());
         if (sendMsg) {
             sender = messagingProvider.createSender(topics.getEventTopic());
         }
+
+        // load the last distributed offset from the store
+        for (Map.Entry<String, LocalStore> localStoreEntry : this.localStores.entrySet()) {

Review comment:
       Currently `localStoreEntry` starts empty. The loop will never set the `lastDistributedOffsets` field from stored values. This could be solved by loading the `lastDistributedOffsets` if needed and upon use in the `processOffsets` method.
   
   This loop in the activate method would be removed. Computing `minOffset` in `processOffsets` would be done with somethings along the lines of
   
   ```
   long minOffset = Math.min(offsets.get().findFirst().getAsLong(), lastDistributedOffsets.computeIfAbsent(pubAgentName, this::storedLastDistributedOffset));
   ```
   and 
   ```
   private long storedLastDistributedOffset(String pubAgentName) {
       return localStores.computeIfAbsent(pubAgentName, this::newLocalStore).load(STORE_TYPE_OFFSETS, Long.MAX_VALUE);
   }
   ```
   
   The `storeLastDistributedOffset` would no longer create `LocalStore` with `computeIfAbsent` and instead simply skip stores not present in the `localStores` field.

##########
File path: src/main/java/org/apache/sling/distribution/journal/impl/publisher/PackageDistributedNotifier.java
##########
@@ -34,49 +30,69 @@
 import org.apache.sling.distribution.journal.queue.PubQueueProvider;
 import org.apache.sling.distribution.journal.queue.QueueItemFactory;
 import org.apache.sling.distribution.journal.shared.Topics;
-import org.apache.sling.distribution.journal.MessagingProvider;
-
-import org.apache.commons.lang3.StringUtils;
 import org.apache.sling.distribution.queue.DistributionQueueItem;
-import org.osgi.service.component.annotations.Activate;
-import org.osgi.service.component.annotations.Component;
-import org.osgi.service.component.annotations.Reference;
 import org.osgi.service.event.Event;
 import org.osgi.service.event.EventAdmin;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import javax.annotation.ParametersAreNonnullByDefault;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
+import java.util.stream.LongStream;
+
+import static org.apache.sling.distribution.journal.impl.subscriber.DistributionSubscriber.escapeTopicName;
 import static org.apache.sling.distribution.packaging.DistributionPackageInfo.PROPERTY_REQUEST_DEEP_PATHS;
 import static org.apache.sling.distribution.packaging.DistributionPackageInfo.PROPERTY_REQUEST_PATHS;
 
-@Component(immediate = true)
 @ParametersAreNonnullByDefault
 public class PackageDistributedNotifier implements TopologyChangeHandler {
 
     private static final Logger LOG = LoggerFactory.getLogger(PackageDistributedNotifier.class);
 
-    @Reference
-    private EventAdmin eventAdmin;
+    public static final String STORE_TYPE_OFFSETS = "lastRaisedEventOffset";
+
+    private final Map<String, Long> lastDistributedOffsets = new HashMap<>();
 
-    @Reference
-    private PubQueueProvider pubQueueCacheService;
+    private final EventAdmin eventAdmin;
 
-    @Reference
-    private MessagingProvider messagingProvider;
+    private final PubQueueProvider pubQueueCacheService;
+
+    private  MessagingProvider messagingProvider;
 
-    @Reference
     private Topics topics;
 
+    private ResourceResolverFactory resolverFactory;
+
+    private Map<String, LocalStore> localStores;

Review comment:
       `localStores` should be a thread safe `ConcurrentMap` instead of `HashMap` because it'll be accessed from multiple threads: the task that invoke `storeLastDistributedOffset` and the thread that invoke `processOffsets`.




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