mjsax commented on code in PR #21345: URL: https://github.com/apache/kafka/pull/21345#discussion_r2785906354
########## streams/src/main/java/org/apache/kafka/streams/state/internals/ChangeLoggingTimestampedKeyValueBytesStoreWithHeaders.java: ########## @@ -0,0 +1,90 @@ +/* + * 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.utils.Bytes; +import org.apache.kafka.streams.KeyValue; +import org.apache.kafka.streams.state.KeyValueStore; + +import java.util.List; + +import static org.apache.kafka.streams.state.internals.ValueTimestampHeadersDeserializer.rawValue; +import static org.apache.kafka.streams.state.internals.ValueTimestampHeadersDeserializer.timestamp; + +/** + * Change-logging wrapper for a timestamped key-value bytes store whose values also carry headers. + * <p> + * the header-aware serialized value format produced by {@link ValueTimestampHeadersSerializer}. + * <p> + * Semantics: + * - The inner store value format is: + * [ varint header_length ][ header_bytes ][ 8-byte timestamp ][ value_bytes ] + * - The changelog record value logged via {@code log(...)} remains just {@code value_bytes} + * (no timestamp, no headers), and the timestamp is logged separately. + */ +public class ChangeLoggingTimestampedKeyValueBytesStoreWithHeaders + extends ChangeLoggingKeyValueBytesStore { + + ChangeLoggingTimestampedKeyValueBytesStoreWithHeaders(final KeyValueStore<Bytes, byte[]> inner) { + super(inner); + } + + @Override + public void put(final Bytes key, + final byte[] valueTimestampHeaders) { + wrapped().put(key, valueTimestampHeaders); + log( Review Comment: Looking into the code of `KafkaProducer#doSend` and related methods which touch the headers, it sound doable. We would couple ourselves strictly to the serialization format of headers inside the message format thought. While we already use the same format atm we are not tightly coupled atm. So we should consider the implications if we want to do go down this route. For the case that this part of the Kafka message format changes, it would impact KS, and this raised compatibility questions. -- 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]
