nicktelford commented on code in PR #21554: URL: https://github.com/apache/kafka/pull/21554#discussion_r2919307269
########## streams/src/main/java/org/apache/kafka/streams/state/internals/LegacyCheckpointingStateStore.java: ########## @@ -0,0 +1,305 @@ +/* + * 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.kafka.streams.state.internals; + +import org.apache.kafka.common.TopicPartition; +import org.apache.kafka.streams.errors.ProcessorStateException; +import org.apache.kafka.streams.processor.StateStore; +import org.apache.kafka.streams.processor.StateStoreContext; +import org.apache.kafka.streams.processor.TaskId; +import org.apache.kafka.streams.processor.internals.StateDirectory; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.File; +import java.io.IOException; +import java.util.HashMap; +import java.util.Map; +import java.util.Set; + +import static org.apache.kafka.streams.state.internals.OffsetCheckpoint.OFFSET_UNKNOWN; + +public class LegacyCheckpointingStateStore<S extends StateStore, K, V> extends WrappedStateStore<S, K, V> { + public static final String CHECKPOINT_FILE_NAME = ".checkpoint"; + + private static final Logger log = LoggerFactory.getLogger(LegacyCheckpointingStateStore.class); + + static final long OFFSET_DELTA_THRESHOLD_FOR_CHECKPOINT = 10_000L; + + private final boolean eosEnabled; + private final Set<TopicPartition> changelogPartitions; + private final StateDirectory stateDirectory; + private final TaskId taskId; + private final OffsetCheckpoint checkpointFile; + private final String logPrefix; + + private final Map<TopicPartition, Long> offsets = new HashMap<>(); + private Map<TopicPartition, Long> checkpointedOffsets; + private boolean corrupted = false; + + /** + * Wraps the given {@link StateStore} as a {@code LegacyCheckpointingStateStore}, only if it is both + * {@link StateStore#persistent() persistent}, and it does not {@link StateStore#managesOffsets() manage its own offsets}. + */ + @SuppressWarnings("deprecation") + public static <S extends StateStore, K, V> StateStore maybeWrapStore(final S wrapped, + final boolean eosEnabled, + final Set<TopicPartition> changelogPartitions, + final StateDirectory stateDirectory, + final TaskId taskId, + final String logPrefix) { + return wrapped.persistent() && !wrapped.managesOffsets() + ? new LegacyCheckpointingStateStore<>(wrapped, eosEnabled, changelogPartitions, stateDirectory, taskId, logPrefix) + : wrapped; + } + + /** + * Unwraps the given store, only if it is a {@code LegacyCheckpointingStateStore}. + */ + public static StateStore maybeUnwrapStore(final StateStore store) { + return (store instanceof LegacyCheckpointingStateStore<?, ?, ?>) + ? ((LegacyCheckpointingStateStore<?, ?, ?>) store).wrapped() + : store; + } + + public static void maybeMarkCorrupted(final StateStore store) { + if (store instanceof LegacyCheckpointingStateStore<?, ?, ?>) { + ((LegacyCheckpointingStateStore<?, ?, ?>) store).markAsCorrupted(); + } + } + + /** + * Migrates offsets stored in a legacy, global/per-task .checkpoint file into the {@code stores}. + * + * The {@code stores} <em>MUST</em> manage their own offsets (i.e. {@link #managesOffsets()} must be {@code true}. + * They can either do this themselves, or be wrapped in a {@link LegacyCheckpointingStateStore} implementation. + * + * Once this method successfully returns, the legacy {@code .checkpoint} file for the given {@link TaskId} (or the + * global checkpoint, when {@code taskId} is {@code null}), will have been migrated and deleted from the filesystem. + * + * @param logPrefix Log prefix to use for log messages. + * @param stateDirectory The singleton {@link StateDirectory} used for looking up existing checkpoint files. + * @param taskId Either the task ID for regular stores, or {@code null} to migrate global stores. + * @param stores A {@link Map} of {@link TopicPartition changelog partitions} to their {@link StateStore}. For global + * stores, which may have multiple {@link TopicPartition changelog partitions}, stores may appear + * multiple times, once for each of its {@link TopicPartition changelog partitions}. + */ + @SuppressWarnings("deprecation") + public static void migrateLegacyOffsets(final String logPrefix, + final StateDirectory stateDirectory, + final TaskId taskId, + final Map<TopicPartition, StateStore> stores) { + // load legacy per-task checkpoint + final File legacyCheckpointFile = checkpointFileFor(stateDirectory, taskId, null); + + if (legacyCheckpointFile.exists()) { + log.info("Migrating legacy checkpoint file for task {}", taskId); + final OffsetCheckpoint legacyCheckpoint = new OffsetCheckpoint(legacyCheckpointFile); + + try { + // build offsets for each store + final Map<StateStore, Map<TopicPartition, Long>> storesToMigrate = new HashMap<>(); + for (final Map.Entry<TopicPartition, Long> entry : legacyCheckpoint.read().entrySet()) { + final StateStore store = stores.get(entry.getKey()); + if (store != null) { + storesToMigrate.computeIfAbsent(store, k -> new HashMap<>()).put(entry.getKey(), entry.getValue()); + } + } + + // commit checkpointed offsets to each store + for (final Map.Entry<StateStore, Map<TopicPartition, Long>> entry : storesToMigrate.entrySet()) { + final StateStore store = entry.getKey(); + if (!store.managesOffsets()) { + log.warn("{}Error migrating legacy checkpoint offsets: StateStore '{}' does not manage its own offsets. " + Review Comment: > But, given the way the code is, would this even happen in practice? It _shouldn't_, which is why I added the bit about it being a bug in Kafka Streams to the warning :grin: -- 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]
