[GitHub] [ignite] nizhikov commented on a change in pull request #8909: IGNITE-13581 Capture Data Change implementation

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

nizhikov commented on a change in pull request #8909:
URL: https://github.com/apache/ignite/pull/8909#discussion_r606162184



##########
File path: modules/core/src/main/java/org/apache/ignite/internal/cdc/IgniteCDC.java
##########
@@ -0,0 +1,457 @@
+/*
+ * 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.io.File;
+import java.io.IOException;
+import java.io.Serializable;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.stream.Stream;
+import org.apache.ignite.IgniteCheckedException;
+import org.apache.ignite.IgniteException;
+import org.apache.ignite.IgniteLogger;
+import org.apache.ignite.cdc.CaptureDataChangeConfiguration;
+import org.apache.ignite.cdc.CaptureDataChangeConsumer;
+import org.apache.ignite.cdc.ChangeEvent;
+import org.apache.ignite.configuration.DataStorageConfiguration;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.internal.IgniteInterruptedCheckedException;
+import org.apache.ignite.internal.IgnitionEx;
+import org.apache.ignite.internal.MarshallerContextImpl;
+import org.apache.ignite.internal.pagemem.wal.WALIterator;
+import org.apache.ignite.internal.processors.cache.binary.CacheObjectBinaryProcessorImpl;
+import org.apache.ignite.internal.processors.cache.persistence.filename.PdsFolderResolver;
+import org.apache.ignite.internal.processors.cache.persistence.filename.PdsFolderSettings;
+import org.apache.ignite.internal.processors.cache.persistence.wal.WALPointer;
+import org.apache.ignite.internal.processors.cache.persistence.wal.reader.IgniteWalIteratorFactory;
+import org.apache.ignite.internal.util.typedef.F;
+import org.apache.ignite.internal.util.typedef.internal.CU;
+import org.apache.ignite.internal.util.typedef.internal.U;
+import org.apache.ignite.lang.IgniteBiTuple;
+
+import static org.apache.ignite.internal.pagemem.wal.record.WALRecord.RecordType.DATA_RECORD_V2;
+import static org.apache.ignite.internal.processors.cache.persistence.wal.FileWriteAheadLogManager.WAL_NAME_PATTERN;
+
+/**
+ * CDC(Capture Data Change) application.
+ * Application run independently of Ignite node process and provide ability for the {@link CaptureDataChangeConsumer} to consume events({@link ChangeEvent}) from WAL segments.
+ * User should responsible {@link CaptureDataChangeConsumer} implementation with custom consumption logic.
+ *
+ * Ignite node should be explicitly configured for using {@link IgniteCDC}.
+ * <ol>
+ *     <li>Set {@link DataStorageConfiguration#setCdcEnabled(boolean)} to true.</li>
+ *     <li>Optional: Set {@link DataStorageConfiguration#setCdcPath(String)} to path to the directory to store WAL segments for CDC.</li>
+ *     <li>Optional: Set {@link DataStorageConfiguration#setWalForceArchiveTimeout(long)} to configure timeout for force WAL rollover,
+ *     so new events will be available for consumptions with the predicted time.</li>
+ * </ol>
+ *
+ * When {@link DataStorageConfiguration#getCdcPath()} is true then Ignite node on each WAL segment rollover creates hard link
+ * to archive WAL segment in {@link DataStorageConfiguration#getCdcPath()} directory.
+ * {@link IgniteCDC} application takes segment file and consumes events from it. After successful consumption (see {@link CaptureDataChangeConsumer#onChange(Iterator)})
+ * WAL segment will be deleted from directory.
+ *
+ * Several Ignite nodes can be started on the same host.
+ * If your deployment done with custom consistent id then you should specify it via {@link IgniteConfiguration#setConsistentId(Serializable)} in provided {@link IgniteConfiguration}.
+ *
+ * Application works as follows:
+ * <ol>
+ *     <li>Search node work directory based on provided {@link IgniteConfiguration}.</li>
+ *     <li>Await for creation of CDC directory if it not exists.</li>
+ *     <li>Acquire file lock to ensure exclusive consumption.</li>
+ *     <li>Loads state of consumption if it exists.</li>
+ *     <li>Infinetely wait for new available segment and process it.</li>
+ * </ol>
+ *
+ * @see DataStorageConfiguration#setCdcEnabled(boolean)
+ * @see DataStorageConfiguration#setCdcPath(String)
+ * @see DataStorageConfiguration#setWalForceArchiveTimeout(long)
+ * @see CommandLineStartup
+ * @see CaptureDataChangeConsumer
+ * @see DataStorageConfiguration#DFLT_CDC_PATH
+ */
+public class IgniteCDC implements Runnable {

Review comment:
       Fixed.




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