modules/vfs-class-loader/src/main/java/org/apache/accumulo/classloader/vfs/context/ReloadingVFSContextClassLoaderFactory.java - accumulo-classloaders - Git at Google

 /*
  * 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.accumulo.classloader.vfs.context;

 import java.io.File;
 import java.net.URI;
 import java.nio.file.Files;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;

 import org.apache.accumulo.classloader.vfs.AccumuloVFSClassLoader;
 import org.apache.accumulo.core.client.PluginEnvironment.Configuration;
 import org.apache.accumulo.core.spi.common.ContextClassLoaderFactory;
 import org.apache.commons.io.FileUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import com.google.gson.Gson;

 /**
  * A ClassLoaderFactory implementation that uses a ReloadingVFSClassLoader per defined context.
  * Configuration of this class is done with a JSON file whose location is defined by the system
  * property <b>vfs.context.class.loader.config</b>. To use this ClassLoaderFactory you need to set
  * the Accumulo configuration property <b>general.context.class.loader.factory</b> to the fully
  * qualified name of this class, create a configuration file that defines the supported contexts and
  * their configuration, and set the system property <b>vfs.context.class.loader.config</b> to the
  * location of the configuration file.
  *
  * <p>
  * Example configuration file:
  *
  * <pre>
  * {
  *  "contexts": [
  *    {
  *      "name": "cx1",
  *      "config": {
  *        "classPath": "file:///tmp/foo",
  *        "postDelegate": true,
  *        "monitorIntervalMs": 30000
  *      }
  *    },
  *    {
  *      "name": "cx2",
  *      "config": {
  *        "classPath": "file:///tmp/bar",
  *        "postDelegate": false,
  *        "monitorIntervalMs": 30000
  *      }
  *    }
  *  ]
  * }
  * </pre>
  */
 public class ReloadingVFSContextClassLoaderFactory implements ContextClassLoaderFactory {

   public static class Contexts {
     List<Context> contexts;

     public List<Context> getContexts() {
       return contexts;
     }

     public void setContexts(List<Context> contexts) {
       this.contexts = contexts;
     }

     @Override
     public String toString() {
       return "Contexts [contexts=" + contexts + "]";
     }

     @Override
     public int hashCode() {
       final int prime = 31;
       int result = 1;
       result = prime * result + ((contexts == null) ? 0 : contexts.hashCode());
       return result;
     }

     @Override
     public boolean equals(Object obj) {
       if (this == obj)
         return true;
       if (obj == null)
         return false;
       if (getClass() != obj.getClass())
         return false;
       Contexts other = (Contexts) obj;
       if (contexts == null) {
         if (other.contexts != null)
           return false;
       } else if (!contexts.equals(other.contexts))
         return false;
       return true;
     }
   }

   public static class Context {
     private String name;
     private ContextConfig config;

     public String getName() {
       return name;
     }

     public void setName(String name) {
       this.name = name;
     }

     public ContextConfig getConfig() {
       return config;
     }

     public void setConfig(ContextConfig config) {
       this.config = config;
     }

     @Override
     public String toString() {
       return "Context [name=" + name + ", config=" + config + "]";
     }

     @Override
     public int hashCode() {
       final int prime = 31;
       int result = 1;
       result = prime * result + ((config == null) ? 0 : config.hashCode());
       result = prime * result + ((name == null) ? 0 : name.hashCode());
       return result;
     }

     @Override
     public boolean equals(Object obj) {
       if (this == obj)
         return true;
       if (obj == null)
         return false;
       if (getClass() != obj.getClass())
         return false;
       Context other = (Context) obj;
       if (config == null) {
         if (other.config != null)
           return false;
       } else if (!config.equals(other.config))
         return false;
       if (name == null) {
         if (other.name != null)
           return false;
       } else if (!name.equals(other.name))
         return false;
       return true;
     }
   }

   public static class ContextConfig {
     private String classPath;
     private boolean postDelegate;
     private long monitorIntervalMs;

     public String getClassPath() {
       return classPath;
     }

     public void setClassPath(String classPath) {
       this.classPath = AccumuloVFSClassLoader.replaceEnvVars(classPath, System.getenv());
     }

     public boolean getPostDelegate() {
       return postDelegate;
     }

     public void setPostDelegate(boolean postDelegate) {
       this.postDelegate = postDelegate;
     }

     public long getMonitorIntervalMs() {
       return monitorIntervalMs;
     }

     public void setMonitorIntervalMs(long monitorIntervalMs) {
       this.monitorIntervalMs = monitorIntervalMs;
     }

     @Override
     public String toString() {
       return "ContextConfig [classPath=" + classPath + ", postDelegate=" + postDelegate
           + ", monitorIntervalMs=" + monitorIntervalMs + "]";
     }

     @Override
     public int hashCode() {
       final int prime = 31;
       int result = 1;
       result = prime * result + ((classPath == null) ? 0 : classPath.hashCode());
       result = prime * result + (int) (monitorIntervalMs ^ (monitorIntervalMs >>> 32));
       result = prime * result + (postDelegate ? 1231 : 1237);
       return result;
     }

     @Override
     public boolean equals(Object obj) {
       if (this == obj)
         return true;
       if (obj == null)
         return false;
       if (getClass() != obj.getClass())
         return false;
       ContextConfig other = (ContextConfig) obj;
       if (classPath == null) {
         if (other.classPath != null)
           return false;
       } else if (!classPath.equals(other.classPath))
         return false;
       if (monitorIntervalMs != other.monitorIntervalMs)
         return false;
       if (postDelegate != other.postDelegate)
         return false;
       return true;
     }
   }

   private static final Logger LOG =
       LoggerFactory.getLogger(ReloadingVFSContextClassLoaderFactory.class);
   public static final String CONFIG_LOCATION = "vfs.context.class.loader.config";
   private static final Map<String,AccumuloVFSClassLoader> CONTEXTS = new ConcurrentHashMap<>();
   private Contexts contextDefinitions = null;

   protected String getConfigFileLocation() {
     String loc = System.getProperty(CONFIG_LOCATION);
     if (null == loc || loc.isBlank()) {
       throw new RuntimeException(CONFIG_LOCATION
           + " system property must be set to use ReloadingVFSContextClassLoaderFactory");
     }
     return loc;
   }

   @Override
   public void initialize(Configuration contextProperties) throws Exception {
     // Properties
     String conf = getConfigFileLocation();
     File f = new File(new URI(conf));
     if (!f.canRead()) {
       throw new RuntimeException("Unable to read configuration file: " + conf);
     }
     Gson g = new Gson();
     LOG.debug("Context configuration: {}", FileUtils.readFileToString(f, "UTF-8"));
     contextDefinitions = g.fromJson(Files.newBufferedReader(f.toPath()), Contexts.class);
     LOG.debug("Deserialized JSON: {}", contextDefinitions);
     contextDefinitions.getContexts().forEach(c -> {
       CONTEXTS.put(c.getName(), create(c));
     });
   }

   protected AccumuloVFSClassLoader create(Context c) {
     LOG.debug("Creating ReloadingVFSClassLoader for context: {})", c.getName());
     return AccessController.doPrivileged(new PrivilegedAction<AccumuloVFSClassLoader>() {
       @Override
       public AccumuloVFSClassLoader run() {
         return new AccumuloVFSClassLoader(
             ReloadingVFSContextClassLoaderFactory.class.getClassLoader()) {
           @Override
           protected String getClassPath() {
             return c.getConfig().getClassPath();
           }

           @Override
           protected boolean isPostDelegationModel() {
             LOG.debug("isPostDelegationModel called, returning {}",
                 c.getConfig().getPostDelegate());
             return c.getConfig().getPostDelegate();
           }

           @Override
           protected long getMonitorInterval() {
             return c.getConfig().getMonitorIntervalMs();
           }

           @Override
           protected boolean isVMInitialized() {
             // The classloader is not being set using
             // `java.system.class.loader`, so the VM is initialized.
             return true;
           }
         };
       }
     });
   }

   @Override
   public synchronized ClassLoader getClassLoader(String contextName)
       throws IllegalArgumentException {
     if (!CONTEXTS.containsKey(contextName)) {
       throw new IllegalArgumentException(
           "ReloadingVFSContextClassLoaderFactory not configured for context: " + contextName);
     }
     // The JVM maintains a cache of loaded classes where the key is the ClassLoader
     // instance and the loaded Class name (see ClassLoader.findLoadedClass()). So
     // that we can return new implementations of the same class when the context
     // changes we need to load the class from the delegate classloader directly
     // since the delegate instance will be recreated when the context changes.
     return CONTEXTS.get(contextName).unwrap();
   }

   public void closeForTests() {
     CONTEXTS.forEach((k, v) -> {
       v.close();
     });
   }
 }
	/*
	* 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.accumulo.classloader.vfs.context;

	import java.io.File;
	import java.net.URI;
	import java.nio.file.Files;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.util.List;
	import java.util.Map;
	import java.util.concurrent.ConcurrentHashMap;

	import org.apache.accumulo.classloader.vfs.AccumuloVFSClassLoader;
	import org.apache.accumulo.core.client.PluginEnvironment.Configuration;
	import org.apache.accumulo.core.spi.common.ContextClassLoaderFactory;
	import org.apache.commons.io.FileUtils;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import com.google.gson.Gson;

	/**
	* A ClassLoaderFactory implementation that uses a ReloadingVFSClassLoader per defined context.
	* Configuration of this class is done with a JSON file whose location is defined by the system
	* property <b>vfs.context.class.loader.config</b>. To use this ClassLoaderFactory you need to set
	* the Accumulo configuration property <b>general.context.class.loader.factory</b> to the fully
	* qualified name of this class, create a configuration file that defines the supported contexts and
	* their configuration, and set the system property <b>vfs.context.class.loader.config</b> to the
	* location of the configuration file.
	*
	* <p>
	* Example configuration file:
	*
	* <pre>
	* {
	* "contexts": [
	* {
	* "name": "cx1",
	* "config": {
	* "classPath": "file:///tmp/foo",
	* "postDelegate": true,
	* "monitorIntervalMs": 30000
	* }
	* },
	* {
	* "name": "cx2",
	* "config": {
	* "classPath": "file:///tmp/bar",
	* "postDelegate": false,
	* "monitorIntervalMs": 30000
	* }
	* }
	* ]
	* }
	* </pre>
	*/
	public class ReloadingVFSContextClassLoaderFactory implements ContextClassLoaderFactory {

	public static class Contexts {
	List<Context> contexts;

	public List<Context> getContexts() {
	return contexts;
	}

	public void setContexts(List<Context> contexts) {
	this.contexts = contexts;
	}

	@Override
	public String toString() {
	return "Contexts [contexts=" + contexts + "]";
	}

	@Override
	public int hashCode() {
	final int prime = 31;
	int result = 1;
	result = prime * result + ((contexts == null) ? 0 : contexts.hashCode());
	return result;
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj)
	return true;
	if (obj == null)
	return false;
	if (getClass() != obj.getClass())
	return false;
	Contexts other = (Contexts) obj;
	if (contexts == null) {
	if (other.contexts != null)
	return false;
	} else if (!contexts.equals(other.contexts))
	return false;
	return true;
	}
	}

	public static class Context {
	private String name;
	private ContextConfig config;

	public String getName() {
	return name;
	}

	public void setName(String name) {
	this.name = name;
	}

	public ContextConfig getConfig() {
	return config;
	}

	public void setConfig(ContextConfig config) {
	this.config = config;
	}

	@Override
	public String toString() {
	return "Context [name=" + name + ", config=" + config + "]";
	}

	@Override
	public int hashCode() {
	final int prime = 31;
	int result = 1;
	result = prime * result + ((config == null) ? 0 : config.hashCode());
	result = prime * result + ((name == null) ? 0 : name.hashCode());
	return result;
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj)
	return true;
	if (obj == null)
	return false;
	if (getClass() != obj.getClass())
	return false;
	Context other = (Context) obj;
	if (config == null) {
	if (other.config != null)
	return false;
	} else if (!config.equals(other.config))
	return false;
	if (name == null) {
	if (other.name != null)
	return false;
	} else if (!name.equals(other.name))
	return false;
	return true;
	}
	}

	public static class ContextConfig {
	private String classPath;
	private boolean postDelegate;
	private long monitorIntervalMs;

	public String getClassPath() {
	return classPath;
	}

	public void setClassPath(String classPath) {
	this.classPath = AccumuloVFSClassLoader.replaceEnvVars(classPath, System.getenv());
	}

	public boolean getPostDelegate() {
	return postDelegate;
	}

	public void setPostDelegate(boolean postDelegate) {
	this.postDelegate = postDelegate;
	}

	public long getMonitorIntervalMs() {
	return monitorIntervalMs;
	}

	public void setMonitorIntervalMs(long monitorIntervalMs) {
	this.monitorIntervalMs = monitorIntervalMs;
	}

	@Override
	public String toString() {
	return "ContextConfig [classPath=" + classPath + ", postDelegate=" + postDelegate
	+ ", monitorIntervalMs=" + monitorIntervalMs + "]";
	}

	@Override
	public int hashCode() {
	final int prime = 31;
	int result = 1;
	result = prime * result + ((classPath == null) ? 0 : classPath.hashCode());
	result = prime * result + (int) (monitorIntervalMs ^ (monitorIntervalMs >>> 32));
	result = prime * result + (postDelegate ? 1231 : 1237);
	return result;
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj)
	return true;
	if (obj == null)
	return false;
	if (getClass() != obj.getClass())
	return false;
	ContextConfig other = (ContextConfig) obj;
	if (classPath == null) {
	if (other.classPath != null)
	return false;
	} else if (!classPath.equals(other.classPath))
	return false;
	if (monitorIntervalMs != other.monitorIntervalMs)
	return false;
	if (postDelegate != other.postDelegate)
	return false;
	return true;
	}
	}

	private static final Logger LOG =
	LoggerFactory.getLogger(ReloadingVFSContextClassLoaderFactory.class);
	public static final String CONFIG_LOCATION = "vfs.context.class.loader.config";
	private static final Map<String,AccumuloVFSClassLoader> CONTEXTS = new ConcurrentHashMap<>();
	private Contexts contextDefinitions = null;

	protected String getConfigFileLocation() {
	String loc = System.getProperty(CONFIG_LOCATION);
	if (null == loc \|\| loc.isBlank()) {
	throw new RuntimeException(CONFIG_LOCATION
	+ " system property must be set to use ReloadingVFSContextClassLoaderFactory");
	}
	return loc;
	}

	@Override
	public void initialize(Configuration contextProperties) throws Exception {
	// Properties
	String conf = getConfigFileLocation();
	File f = new File(new URI(conf));
	if (!f.canRead()) {
	throw new RuntimeException("Unable to read configuration file: " + conf);
	}
	Gson g = new Gson();
	LOG.debug("Context configuration: {}", FileUtils.readFileToString(f, "UTF-8"));
	contextDefinitions = g.fromJson(Files.newBufferedReader(f.toPath()), Contexts.class);
	LOG.debug("Deserialized JSON: {}", contextDefinitions);
	contextDefinitions.getContexts().forEach(c -> {
	CONTEXTS.put(c.getName(), create(c));
	});
	}

	protected AccumuloVFSClassLoader create(Context c) {
	LOG.debug("Creating ReloadingVFSClassLoader for context: {})", c.getName());
	return AccessController.doPrivileged(new PrivilegedAction<AccumuloVFSClassLoader>() {
	@Override
	public AccumuloVFSClassLoader run() {
	return new AccumuloVFSClassLoader(
	ReloadingVFSContextClassLoaderFactory.class.getClassLoader()) {
	@Override
	protected String getClassPath() {
	return c.getConfig().getClassPath();
	}

	@Override
	protected boolean isPostDelegationModel() {
	LOG.debug("isPostDelegationModel called, returning {}",
	c.getConfig().getPostDelegate());
	return c.getConfig().getPostDelegate();
	}

	@Override
	protected long getMonitorInterval() {
	return c.getConfig().getMonitorIntervalMs();
	}

	@Override
	protected boolean isVMInitialized() {
	// The classloader is not being set using
	// `java.system.class.loader`, so the VM is initialized.
	return true;
	}
	};
	}
	});
	}

	@Override
	public synchronized ClassLoader getClassLoader(String contextName)
	throws IllegalArgumentException {
	if (!CONTEXTS.containsKey(contextName)) {
	throw new IllegalArgumentException(
	"ReloadingVFSContextClassLoaderFactory not configured for context: " + contextName);
	}
	// The JVM maintains a cache of loaded classes where the key is the ClassLoader
	// instance and the loaded Class name (see ClassLoader.findLoadedClass()). So
	// that we can return new implementations of the same class when the context
	// changes we need to load the class from the delegate classloader directly
	// since the delegate instance will be recreated when the context changes.
	return CONTEXTS.get(contextName).unwrap();
	}

	public void closeForTests() {
	CONTEXTS.forEach((k, v) -> {
	v.close();
	});
	}
	}