ijuma commented on code in PR #13041: URL: https://github.com/apache/kafka/pull/13041#discussion_r1056024481
########## storage/src/main/java/org/apache/kafka/server/log/internals/LogDirFailureChannel.java: ########## @@ -0,0 +1,80 @@ +/* + * 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.internals; + +import java.io.IOException; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentMap; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/* + * LogDirFailureChannel allows an external thread to block waiting for new offline log dirs. + * + * There should be a single instance of LogDirFailureChannel accessible by any class that does disk-IO operation. + * If IOException is encountered while accessing a log directory, the corresponding class can add the log directory name + * to the LogDirFailureChannel using maybeAddOfflineLogDir(). Each log directory will be added only once. After a log + * directory is added for the first time, a thread which is blocked waiting for new offline log directories + * can take the name of the new offline log directory out of the LogDirFailureChannel and handle the log failure properly. + * An offline log directory will stay offline until the broker is restarted. + */ +public class LogDirFailureChannel { + private static final Logger log = LoggerFactory.getLogger(LogDirFailureChannel.class); + private final ConcurrentMap<String, String> offlineLogDirs; + private final BlockingQueue<String> offlineLogDirQueue; + + public LogDirFailureChannel(int logDirNum) { + this.offlineLogDirs = new ConcurrentHashMap<>(); + this.offlineLogDirQueue = new ArrayBlockingQueue<>(logDirNum); + } + + public boolean hasOfflineLogDir(String logDir) { + return offlineLogDirs.containsKey(logDir); + } + + /** + * If the given logDir is not already offline, add it to the + * set of offline log dirs and enqueue it to the logDirFailureEvent queue. + * + * @param logDir The offline logDir. + * @param msg Error message. + * @param e Exception instance. + */ + public void maybeAddOfflineLogDir(String logDir, String msg, IOException e) { + log.error(msg, e); + if (offlineLogDirs.putIfAbsent(logDir, logDir) == null) { + offlineLogDirQueue.add(logDir); + } + } + + /** + * Get the next offline log dir from logDirFailureEvent queue. + * The method will wait if necessary until a new offline log directory becomes available + * + * @return The next offline log dir. + */ + public String takeNextOfflineLogDir() { + try { + return offlineLogDirQueue.take(); + } catch (InterruptedException e) { + throw new RuntimeException(e); Review Comment: Why are we changing the behavior here? I think it would be better to throw `InterruptedException` as it did before. The callers are Scala code and should continue to work as before. As we convert the upper layers, we'll have to reconsider the exception handling, but it's simpler to leave things as they are now. ########## storage/src/main/java/org/apache/kafka/server/log/internals/LogDirFailureChannel.java: ########## @@ -0,0 +1,80 @@ +/* + * 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.internals; + +import java.io.IOException; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentMap; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/* + * LogDirFailureChannel allows an external thread to block waiting for new offline log dirs. + * + * There should be a single instance of LogDirFailureChannel accessible by any class that does disk-IO operation. + * If IOException is encountered while accessing a log directory, the corresponding class can add the log directory name + * to the LogDirFailureChannel using maybeAddOfflineLogDir(). Each log directory will be added only once. After a log + * directory is added for the first time, a thread which is blocked waiting for new offline log directories + * can take the name of the new offline log directory out of the LogDirFailureChannel and handle the log failure properly. + * An offline log directory will stay offline until the broker is restarted. + */ +public class LogDirFailureChannel { + private static final Logger log = LoggerFactory.getLogger(LogDirFailureChannel.class); + private final ConcurrentMap<String, String> offlineLogDirs; + private final BlockingQueue<String> offlineLogDirQueue; + + public LogDirFailureChannel(int logDirNum) { + this.offlineLogDirs = new ConcurrentHashMap<>(); + this.offlineLogDirQueue = new ArrayBlockingQueue<>(logDirNum); + } + + public boolean hasOfflineLogDir(String logDir) { + return offlineLogDirs.containsKey(logDir); + } + + /** + * If the given logDir is not already offline, add it to the + * set of offline log dirs and enqueue it to the logDirFailureEvent queue. + * + * @param logDir The offline logDir. + * @param msg Error message. + * @param e Exception instance. + */ + public void maybeAddOfflineLogDir(String logDir, String msg, IOException e) { Review Comment: The message was computed lazily before and it's no longer the case. It's ok in this case since we immediately force it when we call `log.error`, but I wanted to highlight the change. -- 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
