satishd commented on a change in pull request #10271: URL: https://github.com/apache/kafka/pull/10271#discussion_r616851984
########## File path: storage/src/main/java/org/apache/kafka/server/log/remote/metadata/storage/serialization/RemoteLogMetadataContextSerdes.java ########## @@ -0,0 +1,123 @@ +/* + * 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.server.log.remote.metadata.storage.serialization; + +import org.apache.kafka.common.serialization.Deserializer; +import org.apache.kafka.common.serialization.Serde; +import org.apache.kafka.common.serialization.Serializer; +import org.apache.kafka.server.log.remote.metadata.storage.RemoteLogMetadataContext; +import org.apache.kafka.server.log.remote.metadata.storage.generated.RemoteLogSegmentMetadataRecord; +import org.apache.kafka.server.log.remote.metadata.storage.generated.RemoteLogSegmentMetadataUpdateRecord; +import org.apache.kafka.server.log.remote.metadata.storage.generated.RemotePartitionDeleteMetadataRecord; + +import java.nio.ByteBuffer; +import java.util.HashMap; +import java.util.Map; + +/** + * This class provides serialization and deserialization for {@link RemoteLogMetadataContext}. This is the root serdes + * for the messages that are stored in internal remote log metadata topic. + */ +public class RemoteLogMetadataContextSerdes implements Serde<RemoteLogMetadataContext> { + + public static final byte REMOTE_LOG_SEGMENT_METADATA_API_KEY = (byte) new RemoteLogSegmentMetadataRecord().apiKey(); + public static final byte REMOTE_LOG_SEGMENT_METADATA_UPDATE_API_KEY = (byte) new RemoteLogSegmentMetadataUpdateRecord().apiKey(); + public static final byte REMOTE_PARTITION_DELETE_API_KEY = (byte) new RemotePartitionDeleteMetadataRecord().apiKey(); + + private static final Map<Byte, RemoteLogMetadataSerdes> KEY_TO_SERDES = createInternalSerde(); + + private final Deserializer<RemoteLogMetadataContext> rootDeserializer; + private final Serializer<RemoteLogMetadataContext> rootSerializer; + + public RemoteLogMetadataContextSerdes() { + rootSerializer = (topic, data) -> serialize(data); Review comment: There are only two layers currently exist for serialization. Even with ApiMessageSerde, there will be at least two layers but the ApiMessageSerde can be reused in future. I plan to rename RemoteLogMetadataSerde to RemoteLogMetadataTransform - to avoid confusion with serde methods like seriaize/deserialize. - as it is really a transform of POJO to APIMessageAndVersion or vice versa. For ApiMessageSerde, I plan to reuse ApiMessageAndVersion as you suggested earlier. This will be similar to the below code. ``` /** * This abstract class provides serialization/deserialization of {@code ApiMessageAndVersion}. * <p></p> * Implementors need to extend this class and implement {@link #apiMessageFor(short)} method to return a respective * {@code ApiMessage} for the given {@code apiKey}. This is required to deserialize the bytes to build the respective * {@code ApiMessage} instance. */ public abstract class AbstractApiMessageAndVersionSerde implements Serde<ApiMessageAndVersion> { private final Serializer<ApiMessageAndVersion> serializer; private final Deserializer<ApiMessageAndVersion> deserializer; public AbstractApiMessageAndVersionSerde() { serializer = (topic, data) -> doSerialize(data); deserializer = (topic, data) -> doDeserialize(data); } private byte[] doSerialize(ApiMessageAndVersion messageAndVersion) { ObjectSerializationCache cache = new ObjectSerializationCache(); short version = messageAndVersion.version(); ApiMessage message = messageAndVersion.message(); // Add header containing apiKey and apiVersion, // headerSize is 1 byte for apiKey and 1 byte for apiVersion int headerSize = 1 + 1; int messageSize = message.size(cache, version); ByteBufferAccessor writable = new ByteBufferAccessor(ByteBuffer.allocate(headerSize + messageSize)); // Write apiKey and version writable.writeUnsignedVarint(message.apiKey()); writable.writeUnsignedVarint(version); // Write the message message.write(writable, cache, version); return writable.buffer().array(); } private ApiMessageAndVersion doDeserialize(byte[] data) { ByteBufferAccessor readable = new ByteBufferAccessor(ByteBuffer.wrap(data)); short apiKey = (short) readable.readUnsignedVarint(); short version = (short) readable.readUnsignedVarint(); ApiMessage message = apiMessageFor(apiKey); message.read(readable, version); return new ApiMessageAndVersion(message, version); } /** * Return {@code ApiMessage} instance for the given {@code apiKey}. This is used while deserializing the bytes * payload into the respective {@code ApiMessage} in {@link #doDeserialize(byte[])} method. * * @param apiKey apiKey for which a {@code ApiMessage} to be created. */ public abstract ApiMessage apiMessageFor(short apiKey); @Override public Serializer<ApiMessageAndVersion> serializer() { return serializer; } @Override public Deserializer<ApiMessageAndVersion> deserializer() { return deserializer; } } ``` ``` /** * This interface is about transforming metadata objects into the respective {@link ApiMessageAndVersion} or vice versa. * <p></p> * Those metadata objects can be {@link org.apache.kafka.server.log.remote.storage.RemoteLogSegmentMetadata}, * {@link org.apache.kafka.server.log.remote.storage.RemoteLogSegmentMetadataUpdate}, or {@link org.apache.kafka.server.log.remote.storage.RemotePartitionDeleteMetadata}. * <p> * @param <T> metadata type. * * @see RemoteLogSegmentMetadataTransform * @see RemoteLogSegmentMetadataUpdateTransform * @see RemotePartitionDeleteMetadataTransform */ public interface RemoteLogMetadataTransform<T> { /** * Transforms the given {@code metadata} object into the respective {@code ApiMessageAndVersion} object. * * @param metadata metadata object to be serialized. * @return transformed {@code ApiMessageAndVersion} object. */ ApiMessageAndVersion toApiMessageAndVersion(T metadata); /** * Return the deserialized object for the given payload and the version. * * @param apiMessageAndVersion ApiMessageAndVersion object to be transformed. * @return transformed {@code T} metadata object. */ T fromApiMessageAndVersion(ApiMessageAndVersion apiMessageAndVersion); } ``` -- This is an automated message from the Apache Git Service. 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