001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017
018package org.apache.logging.log4j.core.osgi;
019
020import java.util.concurrent.atomic.AtomicReference;
021
022import org.apache.logging.log4j.LogManager;
023import org.apache.logging.log4j.Logger;
024import org.apache.logging.log4j.core.config.plugins.util.PluginRegistry;
025import org.apache.logging.log4j.core.util.Constants;
026import org.apache.logging.log4j.status.StatusLogger;
027import org.apache.logging.log4j.util.PropertiesUtil;
028import org.osgi.framework.Bundle;
029import org.osgi.framework.BundleActivator;
030import org.osgi.framework.BundleContext;
031import org.osgi.framework.BundleEvent;
032import org.osgi.framework.SynchronousBundleListener;
033import org.osgi.framework.wiring.BundleWiring;
034
035/**
036 * OSGi BundleActivator.
037 */
038public final class Activator implements BundleActivator, SynchronousBundleListener {
039
040    private static final Logger LOGGER = StatusLogger.getLogger();
041
042    private final AtomicReference<BundleContext> contextRef = new AtomicReference<>();
043
044    @Override
045    public void start(final BundleContext context) throws Exception {
046        // allow the user to override the default ContextSelector (e.g., by using BasicContextSelector for a global cfg)
047        if (PropertiesUtil.getProperties().getStringProperty(Constants.LOG4J_CONTEXT_SELECTOR) == null) {
048            System.setProperty(Constants.LOG4J_CONTEXT_SELECTOR, BundleContextSelector.class.getName());
049        }
050        if (this.contextRef.compareAndSet(null, context)) {
051            context.addBundleListener(this);
052            // done after the BundleListener as to not miss any new bundle installs in the interim
053            scanInstalledBundlesForPlugins(context);
054        }
055    }
056
057    private static void scanInstalledBundlesForPlugins(final BundleContext context) {
058        final Bundle[] bundles = context.getBundles();
059        for (final Bundle bundle : bundles) {
060            // LOG4J2-920: don't scan system bundle for plugins
061            if (bundle.getState() == Bundle.ACTIVE && bundle.getBundleId() != 0) {
062                // TODO: bundle state can change during this
063                scanBundleForPlugins(bundle);
064            }
065        }
066    }
067
068    private static void scanBundleForPlugins(final Bundle bundle) {
069        LOGGER.trace("Scanning bundle [{}] for plugins.", bundle.getSymbolicName());
070        PluginRegistry.getInstance().loadFromBundle(bundle.getBundleId(),
071            bundle.adapt(BundleWiring.class).getClassLoader());
072    }
073
074    private static void stopBundlePlugins(final Bundle bundle) {
075        LOGGER.trace("Stopping bundle [{}] plugins.", bundle.getSymbolicName());
076        // TODO: plugin lifecycle code
077        PluginRegistry.getInstance().clearBundlePlugins(bundle.getBundleId());
078    }
079
080    @Override
081    public void stop(final BundleContext context) throws Exception {
082        this.contextRef.compareAndSet(context, null);
083        LogManager.shutdown();
084    }
085
086    @Override
087    public void bundleChanged(final BundleEvent event) {
088        switch (event.getType()) {
089            // FIXME: STARTING instead of STARTED?
090            case BundleEvent.STARTED:
091                scanBundleForPlugins(event.getBundle());
092                break;
093
094            case BundleEvent.STOPPING:
095                stopBundlePlugins(event.getBundle());
096                break;
097
098            default:
099                break;
100        }
101    }
102}