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/**
* Copyright Terracotta, Inc.
*
* Licensed 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 net.sf.ehcache.management;
import net.sf.ehcache.CacheException;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.config.ManagementRESTServiceConfiguration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.net.URL;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.ServiceLoader;
/**
* ManagementServerLoader is a facility class to access the rest management interface
* One would use it from EhCache or QuartzScheduler to start or stop a new rest management interface
* or to simply register a cache or a scheduler to an already started management interface.
*
* It uses internally a ResourceClassLoader to load classes from a rest agent jar.
*
* @author Anthony Dahanne
*/
public class ManagementServerLoader {
static final Map MGMT_SVR_BY_BIND = new HashMap();
private static final String PRIVATE_CLASSPATH = "rest-management-private-classpath";
private static final Class MANAGEMENT_SERVER_CLASS;
private static final ClassLoader RESOURCE_CLASS_LOADER;
private static final Logger LOG = LoggerFactory.getLogger(ManagementServerLoader.class);
static {
URL depsResource = DevModeClassLoader.devModeResource();
if (depsResource != null) {
RESOURCE_CLASS_LOADER = new DevModeClassLoader(depsResource, CacheManager.class.getClassLoader());
} else {
RESOURCE_CLASS_LOADER = new ResourceClassLoader(PRIVATE_CLASSPATH, CacheManager.class.getClassLoader());
}
LOG.info("XXX: using classloader: " + RESOURCE_CLASS_LOADER);
ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
Class managementServerClass = null;
try {
// because some code in Jersey is using the TCCL to resolve some classes
Thread.currentThread().setContextClassLoader(RESOURCE_CLASS_LOADER);
managementServerClass = RESOURCE_CLASS_LOADER.loadClass("net.sf.ehcache.management.ManagementServer");
} catch (Exception e) {
managementServerClass = null;
if (e.getCause() instanceof ClassNotFoundException) {
LOG.warn("Failed to initialize the ManagementRESTService - Did you include ehcache-rest-agent on the classpath?", e);
} else {
LOG.warn("Failed to load ManagementServer class. Management agent will not be available.", e);
}
} finally {
// setting back the appClassLoader as the TCCL
Thread.currentThread().setContextClassLoader(contextClassLoader);
MANAGEMENT_SERVER_CLASS = managementServerClass;
}
}
/**
* Check if the ehcache-rest-agent jar is on the classpath
*
* @return true if ehcache-rest-agent is available, false otherwise.
*/
public static boolean isManagementAvailable() {
try {
ServiceLoader loader = ServiceLoader.load(ManagementServer.class, RESOURCE_CLASS_LOADER);
Iterator loaderIterator = loader.iterator();
if (loaderIterator.hasNext()) {
return true;
}
} catch (Exception e) {
LOG.warn("Unable to load META-INF/services/net.sf.ehcache.management.ManagementServer ; the management" +
" agent won't be available");
}
return false;
}
/**
* Register a cacheManager to management rest server.
* If the server does not exist, starts it.
*
* @param cacheManager the cacheManager to register
* @param clientUUID the client UUID
* @param managementRESTServiceConfiguration the management configuration
*/
public static void register(CacheManager cacheManager, String clientUUID,
ManagementRESTServiceConfiguration managementRESTServiceConfiguration) {
ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
try {
// because some code in Jersey is using the TCCL to resolve some classes
Thread.currentThread().setContextClassLoader(RESOURCE_CLASS_LOADER);
if (!MGMT_SVR_BY_BIND.containsKey(managementRESTServiceConfiguration.getBind())) {
if (!MGMT_SVR_BY_BIND.isEmpty()) {
String alreadyBound = MGMT_SVR_BY_BIND.keySet().iterator().next();
managementRESTServiceConfiguration.setBind(alreadyBound);
LOG.warn("You cannot have several Ehcache management rest agents running in the same ClassLoader; CacheManager "
+ cacheManager.getName()
+ " will be registered to the already running Ehcache management rest agent "
+ (ManagementRESTServiceConfiguration.NO_BIND.equals(managementRESTServiceConfiguration.getBind()) ?
"reachable through the TSA agent" : "listening on port " + alreadyBound)
+ ", the configuration will not be changed for " + cacheManager.getName());
} else {
new ManagementServerHolder(loadOSorEEManagementServer()).start(managementRESTServiceConfiguration);
}
} else {
LOG.warn("Another CacheManager already instantiated the Ehcache Management rest agent" +
(ManagementRESTServiceConfiguration.NO_BIND.equals(managementRESTServiceConfiguration.getBind()) ?
", reachable through the TSA agent" : ", on port " + managementRESTServiceConfiguration.getBind()) +
", the configuration will not be changed for " + cacheManager.getName());
}
ManagementServerHolder managementServerHolder = MGMT_SVR_BY_BIND.get(managementRESTServiceConfiguration.getBind());
managementServerHolder.register(cacheManager, clientUUID);
} catch (Exception e) {
if (e.getCause() instanceof ClassNotFoundException) {
throw new RuntimeException(
"Failed to initialize the ManagementRESTService - Did you include ehcache-rest-agent on the classpath?", e);
} else {
throw new CacheException("Failed to instantiate ManagementServer.", e);
}
} finally {
// setting back the appClassLoader as the TCCL
Thread.currentThread().setContextClassLoader(contextClassLoader);
}
}
/**
* This method instantiates the ManagementServer implementation found in
* META-INF/services/net.sf.ehcache.management.ManagementServer
*
* @return a {@link ManagementServer} instance
*/
private static Object loadOSorEEManagementServer() throws Exception {
Object managementServerImpl;
ServiceLoader loader = ServiceLoader.load(ManagementServer.class, RESOURCE_CLASS_LOADER);
Iterator loaderIterator = loader.iterator();
if (!loaderIterator.hasNext()) {
LOG.info("Could not find any META-INF/services/net.sf.ehcache.management.ManagementServer using the " +
"ResourceClassLoader; choosing the default OS implementation : " +
"net.sf.ehcache.management.ManagementServerImpl");
Class managementServerImplClass = RESOURCE_CLASS_LOADER
.loadClass("net.sf.ehcache.management.ManagementServerImpl");
Constructor managementServerImplClassConstructor = managementServerImplClass.getConstructor();
managementServerImpl = managementServerImplClassConstructor.newInstance();
} else {
managementServerImpl = loaderIterator.next();
// more than one file found ? is it even possible ? well across multiple jars, why not..
if (loaderIterator.hasNext()) {
throw new RuntimeException("Several META-INF/services/net.sf.ehcache.management.ManagementServer " +
"found in the classpath, aborting agent start up");
}
LOG.info("The ManagementServer implementation that is going to be used is {} .",
managementServerImpl.getClass().toString());
}
return managementServerImpl;
}
/**
* Unregister a cache manager from a management rest server
* If it is the last cache manager bound to this server, stops the server too.
*
* @param registeredMgmtSvrBind the bind identifying what to un-register from
* @param cacheManager the cacheManager to un-register
*/
public static void unregister(String registeredMgmtSvrBind, CacheManager cacheManager) {
ManagementServerHolder managementServerHolder = MGMT_SVR_BY_BIND.get(registeredMgmtSvrBind);
try {
managementServerHolder.unregister(cacheManager);
// there are no more cacheManagers registered to the rest agent, we can now stop it
if (!managementServerHolder.hasRegistered()) {
managementServerHolder.stop(registeredMgmtSvrBind);
}
} catch (Exception e) {
LOG.warn("Failed to shutdown the ManagementRESTService", e);
}
}
static final class ManagementServerHolder {
private Object managementServer;
private final Map clientUUIDs = new HashMap();
ManagementServerHolder(Object managementServer) {
this.managementServer = managementServer;
}
void start(ManagementRESTServiceConfiguration managementRESTServiceConfiguration) throws Exception {
Method initializeMethod = MANAGEMENT_SERVER_CLASS.getMethod("initialize", ManagementRESTServiceConfiguration.class);
initializeMethod.invoke(managementServer, managementRESTServiceConfiguration);
Method startMethod = MANAGEMENT_SERVER_CLASS.getMethod("start");
startMethod.invoke(managementServer);
MGMT_SVR_BY_BIND.put(managementRESTServiceConfiguration.getBind(), this);
}
void register(CacheManager cacheManager, String clientUUID) throws Exception {
Method registerMethod = MANAGEMENT_SERVER_CLASS.getMethod("register", CacheManager.class);
registerMethod.invoke(managementServer, cacheManager);
if (clientUUID != null) {
Method registerClusterRemoteEndpoint = MANAGEMENT_SERVER_CLASS.getMethod("registerClusterRemoteEndpoint", String.class);
registerClusterRemoteEndpoint.invoke(managementServer, clientUUID);
clientUUIDs.put(cacheManager.getName(), clientUUID);
}
}
void unregister(CacheManager cacheManager) throws Exception {
Method unregisterMethod = MANAGEMENT_SERVER_CLASS.getMethod("unregister", CacheManager.class);
unregisterMethod.invoke(managementServer, cacheManager);
String unregisteredClientUUID = clientUUIDs.remove(cacheManager.getName());
if (unregisteredClientUUID != null) {
Method unregisterClusterRemoteEndpoint = MANAGEMENT_SERVER_CLASS.getMethod("unregisterClusterRemoteEndpoint", String.class);
unregisterClusterRemoteEndpoint.invoke(managementServer, unregisteredClientUUID);
}
}
boolean hasRegistered() throws Exception {
Method hasRegisteredMethod = MANAGEMENT_SERVER_CLASS.getMethod("hasRegistered");
return (Boolean)hasRegisteredMethod.invoke(managementServer);
}
void stop(String bind) throws Exception {
try {
Method stopMethod = MANAGEMENT_SERVER_CLASS.getMethod("stop");
stopMethod.invoke(managementServer);
} finally {
MGMT_SVR_BY_BIND.remove(bind);
}
}
public Object getManagementServer() {
return managementServer;
}
}
}