nizhikov commented on code in PR #11044: URL: https://github.com/apache/ignite/pull/11044#discussion_r1404089228
########## modules/core/src/main/java/org/apache/ignite/internal/cdc/CdcManager.java: ########## @@ -0,0 +1,119 @@ +/* + * 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.ignite.internal.cdc; + +import java.nio.ByteBuffer; +import java.util.Iterator; +import org.apache.ignite.IgniteCheckedException; +import org.apache.ignite.IgniteSystemProperties; +import org.apache.ignite.cdc.CdcConsumer; +import org.apache.ignite.internal.pagemem.wal.record.CdcManagerRecord; +import org.apache.ignite.internal.pagemem.wal.record.CdcManagerStopRecord; +import org.apache.ignite.internal.processors.cache.GridCacheSharedManager; +import org.apache.ignite.internal.processors.cache.persistence.DatabaseLifecycleListener; +import org.apache.ignite.internal.processors.cache.persistence.GridCacheDatabaseSharedManager; +import org.apache.ignite.internal.processors.cache.persistence.IgniteCacheDatabaseSharedManager; +import org.apache.ignite.internal.processors.cache.persistence.wal.WALPointer; +import org.apache.ignite.internal.processors.cache.persistence.wal.io.FileInput; +import org.apache.ignite.internal.processors.cache.persistence.wal.serializer.RecordSerializer; +import org.apache.ignite.internal.processors.subscription.GridInternalSubscriptionProcessor; +import org.apache.ignite.plugin.PluginContext; +import org.apache.ignite.plugin.PluginProvider; + +/** + * CDC manager responsible for logic of capturing data within Ignite node. Communication between {@link CdcManager} and + * {@link CdcMain} components is established through CDC management WAL records. {@link CdcManager} logs them, while {@link CdcMain} + * listens to them: + * <ul> + * <li> + * This manager can log {@link CdcManagerRecord} with committed consumer state. This record will be handled by + * {@link CdcMain} the same way it handles {@link CdcConsumer#onEvents(Iterator)} when it returns {@code true}. + * </li> + * <li> + * This manager must log {@link CdcManagerStopRecord} after it stopped handling records by any reason. + * {@link CdcMain} will start consume records instead since {@link CdcManagerRecord#walState()} of + * last consumed {@link CdcManagerRecord}. + * </li> + * <li> + * Apache Ignite provides a default implementation - {@link CdcUtilityActiveCdcManager}. It is disabled from the + * beginning, logs the {@link CdcManagerStopRecord} after Ignite node started, and then delegates consuming CDC + * events to the {@link CdcMain} utility. + * </li> + * </ul> + * + * Apache Ignite can be extended with custom CDC manager. It's required to implement this interface, create own {@link PluginProvider} + * that will return the implementation with {@link PluginProvider#createComponent(PluginContext, Class)} method. + * The {@code Class} parameter in the method is {@code CdcManager} class. + * + * @see CdcConsumer#onEvents(Iterator) + * @see CdcConsumerState#saveCdcMode(CdcMode) + */ +public interface CdcManager extends GridCacheSharedManager, DatabaseLifecycleListener { + /** + * If this manager isn't enabled then Ignite skips notifying the manager with following methods. + * + * @return {@code true} if manager is enabled, otherwise {@code false}. + */ + public boolean enabled(); + + /** + * Callback is executed only once on Ignite node start when binary memory has fully restored and WAL logging is resumed. + * It's executed before the first call of {@link #collect(ByteBuffer)}. + * <p> Implementation suggestions: + * <ul> + * <li> + It's required to register this manager to enable calling this method. The registration is performed with + * {@link GridInternalSubscriptionProcessor#registerDatabaseListener(DatabaseLifecycleListener)}. + * </li> + * <li>Callback can be used for restoring CDC state on Ignite node start, collecting missed events from WAL segments.</li> + * <li>Be aware, this method runs in the Ignite system thread and might lengthen the Ignite start procedure.</li> + * <li>Ignite node will fail in case the method throws an exception.</li> + * </ul> + */ + @Override public void afterBinaryMemoryRestore(IgniteCacheDatabaseSharedManager mgr, Review Comment: Can we keep default empty implementation of this methos? As it done in `DatabaseLifecycleListener` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
