kevinrr888 commented on code in PR #28: URL: https://github.com/apache/accumulo-classloaders/pull/28#discussion_r2456480310
########## modules/classloaders/hdfs-class-loader/src/main/java/org/apache/accumulo/classloader/hdfs/HDFSContextClassLoaderFactory.java: ########## @@ -0,0 +1,498 @@ +/* + * 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.hdfs; + +import java.io.BufferedInputStream; +import java.io.ByteArrayInputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.lang.ref.WeakReference; +import java.net.URL; +import java.net.URLClassLoader; +import java.nio.charset.StandardCharsets; +import java.nio.file.Files; +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; +import java.util.Arrays; +import java.util.Date; +import java.util.List; +import java.util.UUID; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicReference; + +import org.apache.accumulo.core.spi.common.ContextClassLoaderEnvironment; +import org.apache.accumulo.core.spi.common.ContextClassLoaderFactory; +import org.apache.accumulo.core.util.Pair; +import org.apache.accumulo.core.util.Retry; +import org.apache.commons.io.FileUtils; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.fs.FileSystem; +import org.apache.hadoop.fs.Path; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import com.google.common.annotations.VisibleForTesting; +import com.google.gson.Gson; + +import edu.umd.cs.findbugs.annotations.SuppressFBWarnings; + +/** + * A {@link ContextClassLoaderFactory} implementation which uses a {@link URLClassLoader} per + * defined context. To use this class, need to set the Accumulo configuration property + * <b>general.context.class.loader.factory</b> to the fully qualified name of this class. <br> + * <br> + * Configuration of this class is done by having a base directory in HDFS which stores context + * directories. It must be named "contexts" (e.g., "hdfs://test:1234/contexts" could be the base + * directory). The children are specific contexts (names can be anything e.g., "contextA"). The + * "contexts" directory should not contain any other files or directories. Each context directory + * should contain a manifest file <b>manifest.json</b> and JAR files. The context directory defines + * the context name (e.g., "contextA") and the manifest file defines the JAR info for what JARs + * should be in the {@link URLClassLoader} for that context. For example: + * + * <pre> + * { + * "jars": [ + * { + * "name": "Iterators.jar", + * "checksum": "f2ca1bb6c7e907d06dafe4687e579fce76b37e4e93b7605022da52e6ccc26fd2" + * }, + * { + * "name": "IteratorsV2.jar", + * "checksum": "934ee77f70dc82403618c154aa63af6f4ebbe3ac1eaf22df21e7e64f0fb6643d" + * } + * ] + * } + * </pre> + * + * Two system properties need to be set to use this class: <br> + * <b>hdfs.contexts.class.loader.base.dir</b> <br> + * This defines where the context directories exist within HDFS (e.g., "hdfs://test:1234/contexts" + * in our example) <br> + * <b>local.contexts.class.loader.download.dir</b> <br> + * This defines where the context info will be locally downloaded to. Will only download the JARs. + * For example, if set to "/path/to/contexts" and + * {@link HDFSContextClassLoaderFactory#getClassLoader(String)} is called with the argument + * "contextA", will create the local directory "/path/to/contexts/contextA" (note that all parent + * directories will be created if needed), and will download the JARs Iterators.jar and + * IteratorsV2.jar from HDFS to the contextA directory. The {@link URLClassLoader} will be + * constructed from these local JARs, will be associated with "contextA", and will be cached. When + * the class loader is no longer in use, it may be garbage collected at any point, at which point it + * will be removed from the cache and the local context directory (including JARs) will be deleted. + */ +public class HDFSContextClassLoaderFactory implements ContextClassLoaderFactory { + private static final Logger LOG = LoggerFactory.getLogger(HDFSContextClassLoaderFactory.class); + public static final String MANIFEST_FILE_NAME = "manifest.json"; + private static final String HASH_ALG = "SHA-256"; + public static final String HDFS_CONTEXTS_BASE_DIR = "hdfs.contexts.class.loader.base.dir"; + public static final String LOCAL_CONTEXTS_DOWNLOAD_DIR = + "local.contexts.class.loader.download.dir"; + // Save the class loaders for re-use + @VisibleForTesting + ClassLoaderStore<Path,FinalState> classLoaders; + private FileSystem hdfs; + private Path hdfsContextsDir; + private java.nio.file.Path localContextsDir; + private MessageDigest messageDigest; + private final Configuration hadoopConf = new Configuration(); + private final AtomicBoolean shutdownStoreCleaner = new AtomicBoolean(false); + + @VisibleForTesting + class StoreCleaner implements Runnable { + private final long intervalMs; + + StoreCleaner(long intervalMs) { + this.intervalMs = intervalMs; + } + + @Override + public void run() { + while (!shutdownStoreCleaner.get()) { + classLoaders.removeIf(entry -> entry.getValue().shouldClear()); + try { + Thread.sleep(intervalMs); + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + throw new IllegalStateException(e); + } + } + } + } + + @VisibleForTesting + void shutdownStoreCleaner() { + shutdownStoreCleaner.set(true); + } + + /** + * Used to store info needed to create the value in the map + */ + private static final class TempState implements AutoCloseable { + private final String contextName; + private final java.nio.file.Path localTempContextDir; + private final java.nio.file.Path localFinalContextDir; + private final long hdfsManifestLastMod; + private final String hdfsManifestChecksum; + private final URL[] urls; + + private TempState(String contextName, java.nio.file.Path localTempContextDir, + java.nio.file.Path localFinalContextDir, long hdfsManifestLastMod, + String hdfsManifestChecksum, URL[] urls) { + this.contextName = contextName; + this.localTempContextDir = localTempContextDir; + this.localFinalContextDir = localFinalContextDir; + this.hdfsManifestLastMod = hdfsManifestLastMod; + this.hdfsManifestChecksum = hdfsManifestChecksum; + this.urls = urls; + } + + @Override + public void close() throws IOException { + if (localTempContextDir.toFile().exists()) { + FileUtils.deleteDirectory(localTempContextDir.toFile()); + LOG.debug("Creating the class loader for context {} did not fully complete. Deleted the " + + "temp directory {} and all of its contents.", contextName, localTempContextDir); + } + } + } + + private static final class FinalState { + // WeakReference in order to allow for GC when no longer referenced/used elsewhere + private final WeakReference<URLClassLoader> classLoaderWeakRef; + private final long hdfsManifestLastMod; + private final String hdfsManifestChecksum; + + private FinalState(URLClassLoader classLoader, long hdfsManifestLastMod, + String hdfsManifestChecksum) { + this.classLoaderWeakRef = new WeakReference<>(classLoader); + this.hdfsManifestLastMod = hdfsManifestLastMod; + this.hdfsManifestChecksum = hdfsManifestChecksum; + } + + private URLClassLoader getClassLoader() { + return classLoaderWeakRef.get(); + } + + private boolean shouldClear() { + return classLoaderWeakRef.get() == null; + } + + @Override + public String toString() { + var classLoader = getClassLoader(); + if (classLoader == null) { + return getClass().getSimpleName() + "[marked for removal]"; + } + return getClass().getSimpleName() + "[loader object: " + classLoader + ", loader URLs: " + + Arrays.toString(classLoader.getURLs()) + ", manifest file checksum: " + + hdfsManifestChecksum + ", last modification: " + new Date(hdfsManifestLastMod) + "]"; + } + } + + @VisibleForTesting + static class Context { + private final List<JarInfo> jars; + + Context(JarInfo... jars) { + this.jars = List.of(jars); + } + + @SuppressFBWarnings(value = "EI_EXPOSE_REP", justification = "returned list is not modifiable") + List<JarInfo> getJars() { + return jars; + } + } + + @VisibleForTesting + static class JarInfo { + private final String jarName; + private final String checksum; + + JarInfo(String jarName, String checksum) { + this.jarName = jarName; + this.checksum = checksum; + } + + String getJarName() { + return jarName; + } + + String getChecksum() { + return checksum; + } + } + + @Override + public void init(ContextClassLoaderEnvironment env) { + hdfsContextsDir = new Path(System.getProperty(HDFS_CONTEXTS_BASE_DIR)); + localContextsDir = java.nio.file.Path.of(System.getProperty(LOCAL_CONTEXTS_DOWNLOAD_DIR)); + // create the directory to store all the context info, if needed + if (localContextsDir.toFile().mkdirs()) { + LOG.info("Created dir(s) " + localContextsDir); + } + classLoaders = new ClassLoaderStore<>(entry -> { + var context = entry.getKey().getParent().getName(); + var localContextDir = localContextsDir.resolve(context); + try { + FileUtils.deleteDirectory(localContextDir.toFile()); + } catch (IOException e) { + throw new IllegalStateException(e); + } + }); + try { + hdfs = FileSystem.get(hdfsContextsDir.toUri(), hadoopConf); + messageDigest = MessageDigest.getInstance(HASH_ALG); + } catch (IOException e) { + throw new IllegalStateException("could not obtain FileSystem for " + hdfsContextsDir.toUri(), + e); + } catch (NoSuchAlgorithmException e) { + throw new IllegalStateException("no such algorithm: " + HASH_ALG, e); + } + var storeCleaner = new Thread(new StoreCleaner(TimeUnit.SECONDS.toMillis(30))); + storeCleaner.start(); Review Comment: Can make this configurable or change this time. Just set to 30 seconds for now -- 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]
