dlmarion commented on code in PR #30: URL: https://github.com/apache/accumulo-classloaders/pull/30#discussion_r2582011299
########## modules/local-caching-classloader/src/main/java/org/apache/accumulo/classloader/lcc/cache/CacheUtils.java: ########## @@ -0,0 +1,133 @@ +/* + * 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 + * + * https://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.accumulo.classloader.lcc.cache; + +import static java.nio.file.attribute.PosixFilePermission.GROUP_READ; +import static java.nio.file.attribute.PosixFilePermission.OTHERS_READ; +import static java.nio.file.attribute.PosixFilePermission.OWNER_EXECUTE; +import static java.nio.file.attribute.PosixFilePermission.OWNER_READ; +import static java.nio.file.attribute.PosixFilePermission.OWNER_WRITE; +import static java.util.Objects.requireNonNull; + +import java.io.IOException; +import java.net.URI; +import java.nio.channels.FileChannel; +import java.nio.channels.FileLock; +import java.nio.channels.OverlappingFileLockException; +import java.nio.file.FileAlreadyExistsException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.StandardOpenOption; +import java.nio.file.attribute.FileAttribute; +import java.nio.file.attribute.PosixFilePermission; +import java.nio.file.attribute.PosixFilePermissions; +import java.util.EnumSet; +import java.util.Set; + +import org.apache.accumulo.classloader.lcc.Constants; +import org.apache.accumulo.core.spi.common.ContextClassLoaderFactory.ContextClassLoaderException; + +public class CacheUtils { + + private static final Set<PosixFilePermission> CACHE_DIR_PERMS = + EnumSet.of(OWNER_READ, OWNER_WRITE, OWNER_EXECUTE, GROUP_READ, OTHERS_READ); + private static final FileAttribute<Set<PosixFilePermission>> PERMISSIONS = + PosixFilePermissions.asFileAttribute(CACHE_DIR_PERMS); + private static final String lockFileName = "lock_file"; + + public static class LockInfo { + + private final FileChannel channel; + private final FileLock lock; + + public LockInfo(FileChannel channel, FileLock lock) { + this.channel = requireNonNull(channel, "channel must be supplied"); + this.lock = requireNonNull(lock, "lock must be supplied"); + } + + FileChannel getChannel() { + return channel; + } + + FileLock getLock() { + return lock; + } + + public void unlock() throws IOException { + lock.release(); + channel.close(); + } + + } + + private static Path mkdir(final Path p) throws IOException { + try { + return Files.createDirectory(p, PERMISSIONS); + } catch (FileAlreadyExistsException e) { + return p; + } + } + + public static Path createBaseCacheDir() throws IOException, ContextClassLoaderException { + final String prop = Constants.CACHE_DIR_PROPERTY; + final String cacheDir = System.getProperty(prop); + if (cacheDir == null) { + throw new ContextClassLoaderException("System property " + prop + " not set."); + } + return mkdir(Path.of(URI.create(cacheDir))); + } + + public static Path createOrGetContextCacheDir(final String contextName) + throws IOException, ContextClassLoaderException { + Path baseContextDir = createBaseCacheDir(); + return mkdir(baseContextDir.resolve(contextName)); + } + + /** + * Acquire an exclusive lock on the "lock_file" file in the context cache directory. Returns null + * if lock can not be acquired. Caller MUST call LockInfo.unlock when done manipulating the cache + * directory + */ + public static LockInfo lockContextCacheDir(final Path contextCacheDir) Review Comment: Added a test in b2ab523 that uses Mini Accumulo and 3 tservers. -- 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]
