Source code

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.config.plugins.util;
019
020import java.io.IOException;
021import java.net.URI;
022import java.net.URL;
023import java.text.DecimalFormat;
024import java.util.ArrayList;
025import java.util.Collections;
026import java.util.Enumeration;
027import java.util.HashMap;
028import java.util.List;
029import java.util.Map;
030import java.util.concurrent.ConcurrentHashMap;
031import java.util.concurrent.ConcurrentMap;
032import java.util.concurrent.atomic.AtomicReference;
033
034import org.apache.logging.log4j.Logger;
035import org.apache.logging.log4j.core.config.plugins.Plugin;
036import org.apache.logging.log4j.core.config.plugins.PluginAliases;
037import org.apache.logging.log4j.core.config.plugins.processor.PluginCache;
038import org.apache.logging.log4j.core.config.plugins.processor.PluginEntry;
039import org.apache.logging.log4j.core.config.plugins.processor.PluginProcessor;
040import org.apache.logging.log4j.core.util.Loader;
041import org.apache.logging.log4j.status.StatusLogger;
042import org.apache.logging.log4j.util.Strings;
043
044/**
045 * Registry singleton for PluginType maps partitioned by source type and then by category names.
046 */
047public class PluginRegistry {
048
049    private static final Logger LOGGER = StatusLogger.getLogger();
050
051    private static volatile PluginRegistry INSTANCE;
052    private static final Object INSTANCE_LOCK = new Object();
053
054    /**
055     * Contains plugins found in Log4j2Plugins.dat cache files in the main CLASSPATH.
056     */
057    private final AtomicReference<Map<String, List<PluginType<?>>>> pluginsByCategoryRef =
058        new AtomicReference<>();
059
060    /**
061     * Contains plugins found in Log4j2Plugins.dat cache files in OSGi Bundles.
062     */
063    private final ConcurrentMap<Long, Map<String, List<PluginType<?>>>> pluginsByCategoryByBundleId =
064        new ConcurrentHashMap<>();
065
066    /**
067     * Contains plugins found by searching for annotated classes at runtime.
068     */
069    private final ConcurrentMap<String, Map<String, List<PluginType<?>>>> pluginsByCategoryByPackage =
070        new ConcurrentHashMap<>();
071
072    private PluginRegistry() {
073    }
074
075    /**
076     * Returns the global PluginRegistry instance.
077     *
078     * @return the global PluginRegistry instance.
079     * @since 2.1
080     */
081    public static PluginRegistry getInstance() {
082        PluginRegistry result = INSTANCE;
083        if (result == null) {
084            synchronized (INSTANCE_LOCK) {
085                result = INSTANCE;
086                if (result == null) {
087                    INSTANCE = result = new PluginRegistry();
088                }
089            }
090        }
091        return result;
092    }
093
094    /**
095     * Resets the registry to an empty state.
096     */
097    public void clear() {
098        pluginsByCategoryRef.set(null);
099        pluginsByCategoryByPackage.clear();
100        pluginsByCategoryByBundleId.clear();
101    }
102
103    /**
104     * @since 2.1
105     */
106    public Map<Long, Map<String, List<PluginType<?>>>> getPluginsByCategoryByBundleId() {
107        return pluginsByCategoryByBundleId;
108    }
109
110    /**
111     * @since 2.1
112     */
113    public Map<String, List<PluginType<?>>> loadFromMainClassLoader() {
114        final Map<String, List<PluginType<?>>> existing = pluginsByCategoryRef.get();
115        if (existing != null) {
116            // already loaded
117            return existing;
118        }
119        final Map<String, List<PluginType<?>>> newPluginsByCategory = decodeCacheFiles(Loader.getClassLoader());
120
121        // Note multiple threads could be calling this method concurrently. Both will do the work,
122        // but only one will be allowed to store the result in the AtomicReference.
123        // Return the map produced by whichever thread won the race, so all callers will get the same result.
124        if (pluginsByCategoryRef.compareAndSet(null, newPluginsByCategory)) {
125            return newPluginsByCategory;
126        }
127        return pluginsByCategoryRef.get();
128    }
129
130    /**
131     * @since 2.1
132     */
133    public void clearBundlePlugins(final long bundleId) {
134        pluginsByCategoryByBundleId.remove(bundleId);
135    }
136
137    /**
138     * @since 2.1
139     */
140    public Map<String, List<PluginType<?>>> loadFromBundle(final long bundleId, final ClassLoader loader) {
141        Map<String, List<PluginType<?>>> existing = pluginsByCategoryByBundleId.get(bundleId);
142        if (existing != null) {
143            // already loaded from this classloader
144            return existing;
145        }
146        final Map<String, List<PluginType<?>>> newPluginsByCategory = decodeCacheFiles(loader);
147
148        // Note multiple threads could be calling this method concurrently. Both will do the work,
149        // but only one will be allowed to store the result in the outer map.
150        // Return the inner map produced by whichever thread won the race, so all callers will get the same result.
151        existing = pluginsByCategoryByBundleId.putIfAbsent(bundleId, newPluginsByCategory);
152        if (existing != null) {
153            return existing;
154        }
155        return newPluginsByCategory;
156    }
157
158    private Map<String, List<PluginType<?>>> decodeCacheFiles(final ClassLoader loader) {
159        final long startTime = System.nanoTime();
160        final PluginCache cache = new PluginCache();
161        try {
162            final Enumeration<URL> resources = loader.getResources(PluginProcessor.PLUGIN_CACHE_FILE);
163            if (resources == null) {
164                LOGGER.info("Plugin preloads not available from class loader {}", loader);
165            } else {
166                cache.loadCacheFiles(resources);
167            }
168        } catch (final IOException ioe) {
169            LOGGER.warn("Unable to preload plugins", ioe);
170        }
171        final Map<String, List<PluginType<?>>> newPluginsByCategory = new HashMap<>();
172        int pluginCount = 0;
173        for (final Map.Entry<String, Map<String, PluginEntry>> outer : cache.getAllCategories().entrySet()) {
174            final String categoryLowerCase = outer.getKey();
175            final List<PluginType<?>> types = new ArrayList<>(outer.getValue().size());
176            newPluginsByCategory.put(categoryLowerCase, types);
177            for (final Map.Entry<String, PluginEntry> inner : outer.getValue().entrySet()) {
178                final PluginEntry entry = inner.getValue();
179                final String className = entry.getClassName();
180                try {
181                    final Class<?> clazz = loader.loadClass(className);
182                    final PluginType<?> type = new PluginType<>(entry, clazz, entry.getName());
183                    types.add(type);
184                    ++pluginCount;
185                } catch (final ClassNotFoundException e) {
186                    LOGGER.info("Plugin [{}] could not be loaded due to missing classes.", className, e);
187                } catch (final LinkageError e) {
188                    LOGGER.info("Plugin [{}] could not be loaded due to linkage error.", className, e);
189                }
190            }
191        }
192        final int numPlugins = pluginCount;
193        LOGGER.debug(() -> {
194            final long endTime = System.nanoTime();
195            StringBuilder sb = new StringBuilder("Took ");
196            final DecimalFormat numFormat = new DecimalFormat("#0.000000");
197            sb.append(numFormat.format((endTime - startTime) * 1e-9));
198            sb.append(" seconds to load ").append(numPlugins);
199            sb.append(" plugins from ").append(loader);
200            return sb.toString();
201        });
202        return newPluginsByCategory;
203    }
204
205    /**
206     * @since 2.1
207     */
208    public Map<String, List<PluginType<?>>> loadFromPackage(final String pkg) {
209        if (Strings.isBlank(pkg)) {
210            // happens when splitting an empty string
211            return Collections.emptyMap();
212        }
213        Map<String, List<PluginType<?>>> existing = pluginsByCategoryByPackage.get(pkg);
214        if (existing != null) {
215            // already loaded this package
216            return existing;
217        }
218
219        final long startTime = System.nanoTime();
220        final ResolverUtil resolver = new ResolverUtil();
221        final ClassLoader classLoader = Loader.getClassLoader();
222        if (classLoader != null) {
223            resolver.setClassLoader(classLoader);
224        }
225        resolver.findInPackage(new PluginTest(), pkg);
226
227        final Map<String, List<PluginType<?>>> newPluginsByCategory = new HashMap<>();
228        for (final Class<?> clazz : resolver.getClasses()) {
229            final Plugin plugin = clazz.getAnnotation(Plugin.class);
230            final String categoryLowerCase = plugin.category().toLowerCase();
231            List<PluginType<?>> list = newPluginsByCategory.get(categoryLowerCase);
232            if (list == null) {
233                newPluginsByCategory.put(categoryLowerCase, list = new ArrayList<>());
234            }
235            final PluginEntry mainEntry = new PluginEntry();
236            final String mainElementName = plugin.elementType().equals(
237                Plugin.EMPTY) ? plugin.name() : plugin.elementType();
238            mainEntry.setKey(plugin.name().toLowerCase());
239            mainEntry.setName(plugin.name());
240            mainEntry.setCategory(plugin.category());
241            mainEntry.setClassName(clazz.getName());
242            mainEntry.setPrintable(plugin.printObject());
243            mainEntry.setDefer(plugin.deferChildren());
244            final PluginType<?> mainType = new PluginType<>(mainEntry, clazz, mainElementName);
245            list.add(mainType);
246            final PluginAliases pluginAliases = clazz.getAnnotation(PluginAliases.class);
247            if (pluginAliases != null) {
248                for (final String alias : pluginAliases.value()) {
249                    final PluginEntry aliasEntry = new PluginEntry();
250                    final String aliasElementName = plugin.elementType().equals(
251                        Plugin.EMPTY) ? alias.trim() : plugin.elementType();
252                    aliasEntry.setKey(alias.trim().toLowerCase());
253                    aliasEntry.setName(plugin.name());
254                    aliasEntry.setCategory(plugin.category());
255                    aliasEntry.setClassName(clazz.getName());
256                    aliasEntry.setPrintable(plugin.printObject());
257                    aliasEntry.setDefer(plugin.deferChildren());
258                    final PluginType<?> aliasType = new PluginType<>(aliasEntry, clazz, aliasElementName);
259                    list.add(aliasType);
260                }
261            }
262        }
263        LOGGER.debug(() -> {
264            final long endTime = System.nanoTime();
265            StringBuilder sb = new StringBuilder("Took ");
266            final DecimalFormat numFormat = new DecimalFormat("#0.000000");
267            sb.append(numFormat.format((endTime - startTime) * 1e-9));
268            sb.append(" seconds to load ").append(resolver.getClasses().size());
269            sb.append(" plugins from package ").append(pkg);
270            return sb.toString();
271        });
272
273        // Note multiple threads could be calling this method concurrently. Both will do the work,
274        // but only one will be allowed to store the result in the outer map.
275        // Return the inner map produced by whichever thread won the race, so all callers will get the same result.
276        existing = pluginsByCategoryByPackage.putIfAbsent(pkg, newPluginsByCategory);
277        if (existing != null) {
278            return existing;
279        }
280        return newPluginsByCategory;
281    }
282
283    /**
284     * A Test that checks to see if each class is annotated with the 'Plugin' annotation. If it
285     * is, then the test returns true, otherwise false.
286     *
287     * @since 2.1
288     */
289    public static class PluginTest implements ResolverUtil.Test {
290        @Override
291        public boolean matches(final Class<?> type) {
292            return type != null && type.isAnnotationPresent(Plugin.class);
293        }
294
295        @Override
296        public String toString() {
297            return "annotated with @" + Plugin.class.getSimpleName();
298        }
299
300        @Override
301        public boolean matches(final URI resource) {
302            throw new UnsupportedOperationException();
303        }
304
305        @Override
306        public boolean doesMatchClass() {
307            return true;
308        }
309
310        @Override
311        public boolean doesMatchResource() {
312            return false;
313        }
314    }
315}