junrao commented on a change in pull request #11390: URL: https://github.com/apache/kafka/pull/11390#discussion_r818028561
########## File path: storage/src/main/java/org/apache/kafka/server/log/remote/metadata/storage/ClassLoaderAwareRemoteLogMetadataManager.java ########## @@ -0,0 +1,143 @@ +/* + * 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; + +import org.apache.kafka.common.TopicIdPartition; +import org.apache.kafka.server.log.remote.storage.RemoteLogMetadataManager; +import org.apache.kafka.server.log.remote.storage.RemoteLogSegmentMetadata; +import org.apache.kafka.server.log.remote.storage.RemoteLogSegmentMetadataUpdate; +import org.apache.kafka.server.log.remote.storage.RemotePartitionDeleteMetadata; +import org.apache.kafka.server.log.remote.storage.RemoteStorageException; + +import java.io.IOException; +import java.util.Iterator; +import java.util.Map; +import java.util.Optional; +import java.util.Set; +import java.util.concurrent.CompletableFuture; + +public class ClassLoaderAwareRemoteLogMetadataManager implements RemoteLogMetadataManager { + private final RemoteLogMetadataManager delegate; + private final ClassLoader loader; + + public ClassLoaderAwareRemoteLogMetadataManager(RemoteLogMetadataManager delegate, + ClassLoader loader) { + this.delegate = delegate; + this.loader = loader; + } + + @Override + public CompletableFuture<Void> addRemoteLogSegmentMetadata(RemoteLogSegmentMetadata remoteLogSegmentMetadata) throws RemoteStorageException { + return withClassLoader(() -> delegate.addRemoteLogSegmentMetadata(remoteLogSegmentMetadata)); + } + + @Override + public CompletableFuture<Void> updateRemoteLogSegmentMetadata(RemoteLogSegmentMetadataUpdate remoteLogSegmentMetadataUpdate) throws RemoteStorageException { + return withClassLoader(() -> delegate.updateRemoteLogSegmentMetadata(remoteLogSegmentMetadataUpdate)); + } + + @Override + public Optional<RemoteLogSegmentMetadata> remoteLogSegmentMetadata(TopicIdPartition topicIdPartition, + int epochForOffset, + long offset) throws RemoteStorageException { + return withClassLoader(() -> delegate.remoteLogSegmentMetadata(topicIdPartition, epochForOffset, offset)); + } + + @Override + public Optional<Long> highestOffsetForEpoch(TopicIdPartition topicIdPartition, + int leaderEpoch) throws RemoteStorageException { + return withClassLoader(() -> delegate.highestOffsetForEpoch(topicIdPartition, leaderEpoch)); + } + + @Override + public CompletableFuture<Void> putRemotePartitionDeleteMetadata(RemotePartitionDeleteMetadata remotePartitionDeleteMetadata) throws RemoteStorageException { + return withClassLoader(() -> delegate.putRemotePartitionDeleteMetadata(remotePartitionDeleteMetadata) + ); + } + + @Override + public Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicIdPartition topicIdPartition) throws RemoteStorageException { + return withClassLoader(() -> delegate.listRemoteLogSegments(topicIdPartition)); + } + + @Override + public Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicIdPartition topicIdPartition, + int leaderEpoch) throws RemoteStorageException { + return withClassLoader(() -> delegate.listRemoteLogSegments(topicIdPartition, leaderEpoch)); + } + + @Override + public void onPartitionLeadershipChanges(Set<TopicIdPartition> leaderPartitions, + Set<TopicIdPartition> followerPartitions) { + withTryCatchClassLoader(() -> { + delegate.onPartitionLeadershipChanges(leaderPartitions, followerPartitions); + return null; + }); + } + + @Override + public void onStopPartitions(Set<TopicIdPartition> partitions) { + withTryCatchClassLoader(() -> { + delegate.onStopPartitions(partitions); + return null; + }); + } + + @Override + public void configure(Map<String, ?> configs) { + withTryCatchClassLoader(() -> { + delegate.configure(configs); + return null; + }); + } + + @Override + public void close() throws IOException { + ClassLoader originalClassLoader = Thread.currentThread().getContextClassLoader(); + Thread.currentThread().setContextClassLoader(loader); + try { + delegate.close(); + } finally { + Thread.currentThread().setContextClassLoader(originalClassLoader); + } + } + + @SuppressWarnings("UnusedReturnValue") + private <T> T withTryCatchClassLoader(Worker<T> worker) { + try { + return withClassLoader(worker); + } catch (final RemoteStorageException ex) { + // ignore, this exception is not thrown by the method. + } + return null; + } + + private <T> T withClassLoader(Worker<T> worker) throws RemoteStorageException { + ClassLoader originalClassLoader = Thread.currentThread().getContextClassLoader(); + Thread.currentThread().setContextClassLoader(loader); Review comment: The purpose of a special class loader is to address potential class conflicts. If the same class exists btw the plugin and Kafka, by switching the class loader, it seems that we don't know deterministically which version of the class will be loaded, which can be confusing. -- 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
