martongreber commented on code in PR #8: URL: https://github.com/apache/flink-connector-kudu/pull/8#discussion_r1977724995
########## flink-connector-kudu/src/main/java/org/apache/flink/connector/kudu/source/enumerator/KuduSourceEnumerator.java: ########## @@ -0,0 +1,256 @@ +/* + * 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.flink.connector.kudu.source.enumerator; + +import org.apache.flink.api.connector.source.Boundedness; +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.SplitEnumeratorContext; +import org.apache.flink.connector.kudu.connector.KuduTableInfo; +import org.apache.flink.connector.kudu.connector.reader.KuduReaderConfig; +import org.apache.flink.connector.kudu.source.config.ContinuousBoundingSettings; +import org.apache.flink.connector.kudu.source.split.KuduSourceSplit; +import org.apache.flink.connector.kudu.source.split.SplitFinishedEvent; + +import org.apache.kudu.util.HybridTimeUtil; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Iterator; +import java.util.List; +import java.util.Objects; +import java.util.Optional; +import java.util.concurrent.TimeUnit; +import java.util.function.Supplier; + +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * The Kudu source enumerator is responsible for periodically discovering and assigning new splits + * when possible. + * + * <p>To provide CDC-like functionality, the enumeration works as follows: Initially, we perform a + * snapshot read of the table and mark the snapshot time as t0. From that point onward, we perform + * differential scans in the time intervals t0 - t1, t1 - t2, and so on. + * + * <p>This approach means that new splits can only be enumerated once the current time range is + * fully processed. + * + * <p>The process is controlled as follows: + * + * <ul> + * <li>Once a set of splits is enumerated for a time range, we track: + * <ul> + * <li><b>Unassigned splits</b>: Discovered but not yet assigned to readers. + * <li><b>Pending splits</b>: Assigned but not yet fully processed. + * </ul> + * <li>A new set of splits is generated only when there are no remaining unassigned or pending + * splits. + * </ul> + */ +public class KuduSourceEnumerator + implements SplitEnumerator<KuduSourceSplit, KuduSourceEnumeratorState> { + private static final Logger LOG = LoggerFactory.getLogger(KuduSourceEnumerator.class); + + private final SplitEnumeratorContext<KuduSourceSplit> context; + private final List<Integer> readersAwaitingSplit; + private final KuduSplitGenerator splitGenerator; + private final ContinuousBoundingSettings continuousBoundingSettings; + + private long lastEndTimestamp; + private final List<KuduSourceSplit> unassigned; + private final List<KuduSourceSplit> pending; + + public KuduSourceEnumerator( + KuduTableInfo tableInfo, + KuduReaderConfig readerConfig, + ContinuousBoundingSettings continuousBoundingSettings, + SplitEnumeratorContext<KuduSourceSplit> context) { + this( + tableInfo, + readerConfig, + continuousBoundingSettings, + context, + KuduSourceEnumeratorState.empty()); + } + + public KuduSourceEnumerator( + KuduTableInfo tableInfo, + KuduReaderConfig readerConfig, + ContinuousBoundingSettings continuousBoundingSettings, + SplitEnumeratorContext<KuduSourceSplit> context, + KuduSourceEnumeratorState enumState) { + this.continuousBoundingSettings = continuousBoundingSettings; + this.context = checkNotNull(context); + this.readersAwaitingSplit = new ArrayList<>(); + this.unassigned = enumState.getUnassigned(); + this.pending = enumState.getPending(); + this.splitGenerator = new KuduSplitGenerator(readerConfig, tableInfo); + this.lastEndTimestamp = enumState.getLastEndTimestamp(); + } + + @Override + public void start() { + if (continuousBoundingSettings.getBoundedness() == Boundedness.CONTINUOUS_UNBOUNDED + && Objects.nonNull(continuousBoundingSettings.getPeriod())) { + context.callAsync( + () -> enumerateNewSplits(() -> pending.isEmpty() && unassigned.isEmpty()), + this::assignSplits, + 0, + continuousBoundingSettings.getPeriod().toMillis()); + } else { + List<KuduSourceSplit> splits = enumerateNewSplits(() -> true); + if (splits != null) { + unassigned.addAll(enumerateNewSplits(() -> true)); + assignSplitsToReaders(); + } + } + } + + @Override + public void handleSplitRequest(int subtaskId, @Nullable String requesterHostname) { + readersAwaitingSplit.add(subtaskId); + assignSplitsToReaders(); + } + + @Override + public void addSplitsBack(List<KuduSourceSplit> splits, int subtaskId) { + LOG.debug("File Source Enumerator adds splits back: {}", splits); Review Comment: done. -- This is an automated message from the Apache Git Service. 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