ableegoldman commented on code in PR #14735: URL: https://github.com/apache/kafka/pull/14735#discussion_r1414691022
########## streams/src/main/java/org/apache/kafka/streams/processor/StandbyUpdateListener.java: ########## @@ -0,0 +1,85 @@ +/* + * 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.processor; + +import org.apache.kafka.common.TopicPartition; + +public interface StandbyUpdateListener { + + enum SuspendReason { + MIGRATED, + PROMOTED + } + + /** + * A callback that will be invoked after registering the changelogs for each state store in a standby + * task. It is guaranteed to always be invoked before any records are loaded into the standby store. + * + * @param topicPartition the changelog TopicPartition for this standby task + * @param storeName the name of the store being loaded + * @param startingOffset the offset from which the standby task begins consuming from the changelog + */ + void onUpdateStart(final TopicPartition topicPartition, + final String storeName, + final long startingOffset); + + /** + * Method called after loading a batch of records. In this case the maximum size of the batch is whatever + * the value of the MAX_POLL_RECORDS is set to. + * <n> + * This method is called after loading each batch and it is advised to keep processing to a minimum. + * Any heavy processing will block the state updater thread and slow down the rate of standby task + * loading. Therefore, if you need to do any extended processing or connect to an external service, + * consider doing so asynchronously. + * + * @param topicPartition the TopicPartition containing the values to restore + * @param storeName the name of the store undergoing restoration + * @param batchEndOffset batchEndOffset the changelog end offset (inclusive) of the batch that was just loaded + * @param batchSize the total number of records in the batch that was just loaded + * @param currentEndOffset the current end offset of the changelog topic partition. + */ + void onBatchLoaded(final TopicPartition topicPartition, + final String storeName, + final TaskId taskId, + final long batchEndOffset, + final long batchSize, + final long currentEndOffset); + + /** + * This method is called when the corresponding standby task stops updating, for the provided reason. + * <p> + * If the task was {@code MIGRATED} to another instance, this callback will be invoked after this + * state store (and the task itself) are closed (in which case the data will be cleaned up after + * state.cleanup.delay.ms). + * If the task was {@code PROMOTED} to an active task, the state store will not be closed, and the + * callback will be invoked after unregistering it as a standby task but before re-registering it as an active task + * and beginning restoration. In other words, this will always called before the corresponding + * {@link StateRestoreListener#onRestoreStart} call is made. + * + * @param topicPartition the TopicPartition containing the values to restore + * @param storeName the name of the store undergoing restoration Review Comment: ```suggestion * @param topicPartition the changelog TopicPartition for this standby task * @param storeName the name of the store being loaded ``` ########## streams/src/main/java/org/apache/kafka/streams/processor/StandbyUpdateListener.java: ########## @@ -0,0 +1,85 @@ +/* + * 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.processor; + +import org.apache.kafka.common.TopicPartition; + +public interface StandbyUpdateListener { + + enum SuspendReason { + MIGRATED, + PROMOTED + } + + /** + * A callback that will be invoked after registering the changelogs for each state store in a standby + * task. It is guaranteed to always be invoked before any records are loaded into the standby store. + * + * @param topicPartition the changelog TopicPartition for this standby task + * @param storeName the name of the store being loaded + * @param startingOffset the offset from which the standby task begins consuming from the changelog + */ + void onUpdateStart(final TopicPartition topicPartition, + final String storeName, + final long startingOffset); + + /** + * Method called after loading a batch of records. In this case the maximum size of the batch is whatever + * the value of the MAX_POLL_RECORDS is set to. + * <n> + * This method is called after loading each batch and it is advised to keep processing to a minimum. + * Any heavy processing will block the state updater thread and slow down the rate of standby task + * loading. Therefore, if you need to do any extended processing or connect to an external service, + * consider doing so asynchronously. + * + * @param topicPartition the TopicPartition containing the values to restore + * @param storeName the name of the store undergoing restoration Review Comment: ```suggestion * @param topicPartition the changelog TopicPartition for this standby task * @param storeName the name of the store being loaded ``` -- 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: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
