candyleer commented on a change in pull request #4858: URL: https://github.com/apache/skywalking/pull/4858#discussion_r435695928
########## File path: apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/bytebuddy/CacheableTransformerDecorator.java ########## @@ -0,0 +1,192 @@ +/* + * 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.skywalking.apm.agent.core.plugin.bytebuddy; + +import net.bytebuddy.agent.builder.AgentBuilder; +import net.bytebuddy.agent.builder.ResettableClassFileTransformer; +import net.bytebuddy.utility.RandomString; +import org.apache.skywalking.apm.agent.core.logging.api.ILog; +import org.apache.skywalking.apm.agent.core.logging.api.LogManager; +import org.apache.skywalking.apm.agent.core.util.IOUtils; + +import java.io.ByteArrayInputStream; +import java.io.File; +import java.io.FileInputStream; +import java.io.FileOutputStream; +import java.io.IOException; +import java.lang.instrument.IllegalClassFormatException; +import java.nio.file.Files; +import java.security.ProtectionDomain; +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; + +/** + * Wrapper classFileTransformer of ByteBuddy, save the enhanced bytecode to memory cache or file cache, + * and automatically load the previously generated bytecode during the second retransform, + * to solve the problem that ByteBuddy generates auxiliary classes with different random names every time. + * Allow other javaagent to enhance those classes that enhanced by SkyWalking agent. + */ +public class CacheableTransformerDecorator implements AgentBuilder.TransformerDecorator { + + private static final ILog logger = LogManager.getLogger(CacheableTransformerDecorator.class); + + private String cacheDirBase; + private final ClassCacheMode cacheMode; + private ClassCacheResolver cacheResolver; + + public CacheableTransformerDecorator(ClassCacheMode cacheMode) throws IOException { + this.cacheMode = cacheMode; + initClassCache(); + } + + public CacheableTransformerDecorator(ClassCacheMode cacheMode, String cacheDirBase) throws IOException { + this.cacheDirBase = cacheDirBase; + this.cacheMode = cacheMode; + initClassCache(); + } + + private void initClassCache() throws IOException { + if (this.cacheMode.equals(ClassCacheMode.FILE)) { + File cacheDir; + if (this.cacheDirBase == null) { + cacheDir = Files.createTempDirectory("class-cache").toFile(); + } else { + cacheDir = new File(this.cacheDirBase + "/class-cache-" + RandomString.make()); + } + cacheResolver = new FileCacheResolver(cacheDir); + } else { + cacheResolver = new MemoryCacheResolver(); + } + } + + @Override + public ResettableClassFileTransformer decorate(ResettableClassFileTransformer classFileTransformer) { + return new ResettableClassFileTransformer.WithDelegation(classFileTransformer) { + + @Override + public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException { + // load from cache + byte[] classCache = cacheResolver.getClassCache(loader, className); + if (classCache != null) { + return classCache; + } + + //transform class + classfileBuffer = classFileTransformer.transform(loader, className, classBeingRedefined, protectionDomain, classfileBuffer); + + // save to cache + if (classfileBuffer != null) { + cacheResolver.putClassCache(loader, className, classfileBuffer); Review comment: the `key` should be classloader+className,or maybe duplicate in different classloader ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
