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 */
017package org.apache.logging.log4j.core.jmx;
018
019import java.lang.management.ManagementFactory;
020import java.util.List;
021import java.util.Map;
022import java.util.Set;
023import java.util.concurrent.Executor;
024import java.util.concurrent.ExecutorService;
025import java.util.concurrent.Executors;
026
027import javax.management.InstanceAlreadyExistsException;
028import javax.management.MBeanRegistrationException;
029import javax.management.MBeanServer;
030import javax.management.NotCompliantMBeanException;
031import javax.management.ObjectName;
032
033import org.apache.logging.log4j.LogManager;
034import org.apache.logging.log4j.core.Appender;
035import org.apache.logging.log4j.core.LoggerContext;
036import org.apache.logging.log4j.core.appender.AsyncAppender;
037import org.apache.logging.log4j.core.async.AsyncLogger;
038import org.apache.logging.log4j.core.async.AsyncLoggerConfig;
039import org.apache.logging.log4j.core.async.AsyncLoggerContext;
040import org.apache.logging.log4j.core.async.DaemonThreadFactory;
041import org.apache.logging.log4j.core.config.LoggerConfig;
042import org.apache.logging.log4j.core.impl.Log4jContextFactory;
043import org.apache.logging.log4j.core.selector.ContextSelector;
044import org.apache.logging.log4j.core.util.Loader;
045import org.apache.logging.log4j.spi.LoggerContextFactory;
046import org.apache.logging.log4j.status.StatusLogger;
047import org.apache.logging.log4j.util.PropertiesUtil;
048
049/**
050 * Creates MBeans to instrument various classes in the log4j class hierarchy.
051 * <p>
052 * All instrumentation for Log4j 2 classes can be disabled by setting system property {@code -Dlog4j2.disable.jmx=true}.
053 * </p>
054 */
055public final class Server {
056
057    /**
058     * The domain part, or prefix ({@value} ) of the {@code ObjectName} of all MBeans that instrument Log4J2 components.
059     */
060    public static final String DOMAIN = "org.apache.logging.log4j2";
061    private static final String PROPERTY_DISABLE_JMX = "log4j2.disable.jmx";
062    private static final String PROPERTY_ASYNC_NOTIF = "log4j2.jmx.notify.async";
063    private static final String THREAD_NAME_PREFIX = "log4j2.jmx.notif";
064    private static final StatusLogger LOGGER = StatusLogger.getLogger();
065    static final Executor executor = isJmxDisabled() ? null : createExecutor();
066
067    private Server() {
068    }
069
070    /**
071     * Returns either a {@code null} Executor (causing JMX notifications to be sent from the caller thread) or a daemon
072     * background thread Executor, depending on the value of system property "log4j2.jmx.notify.async". If this
073     * property is not set, use a {@code null} Executor for web apps to avoid memory leaks and other issues when the
074     * web app is restarted.
075     * @see <a href="https://issues.apache.org/jira/browse/LOG4J2-938">LOG4J2-938</a>
076     */
077    private static ExecutorService createExecutor() {
078        final boolean defaultAsync = !isWebApp();
079        final boolean async = PropertiesUtil.getProperties().getBooleanProperty(PROPERTY_ASYNC_NOTIF, defaultAsync);
080        return async ? Executors.newFixedThreadPool(1, new DaemonThreadFactory(THREAD_NAME_PREFIX)) : null;
081    }
082
083    /**
084     * Returns {@code true} if we think we are running in a web container, based on the presence of the
085     * {@code javax.servlet.Servlet} class in the classpath.
086     */
087    private static boolean isWebApp() {
088        return Loader.isClassAvailable("javax.servlet.Servlet");
089    }
090
091    /**
092     * Either returns the specified name as is, or returns a quoted value containing the specified name with the special
093     * characters (comma, equals, colon, quote, asterisk, or question mark) preceded with a backslash.
094     *
095     * @param name the name to escape so it can be used as a value in an {@link ObjectName}.
096     * @return the escaped name
097     */
098    public static String escape(final String name) {
099        final StringBuilder sb = new StringBuilder(name.length() * 2);
100        boolean needsQuotes = false;
101        for (int i = 0; i < name.length(); i++) {
102            final char c = name.charAt(i);
103            switch (c) {
104            case '\\':
105            case '*':
106            case '?':
107            case '\"':
108                // quote, star, question & backslash must be escaped
109                sb.append('\\');
110                needsQuotes = true; // ... and can only appear in quoted value
111                break;
112            case ',':
113            case '=':
114            case ':':
115                // no need to escape these, but value must be quoted
116                needsQuotes = true;
117                break;
118            case '\r':
119                // drop \r characters: \\r gives "invalid escape sequence"
120                continue;
121            case '\n':
122                // replace \n characters with \\n sequence
123                sb.append("\\n");
124                needsQuotes = true;
125                continue;
126            }
127            sb.append(c);
128        }
129        if (needsQuotes) {
130            sb.insert(0, '\"');
131            sb.append('\"');
132        }
133        return sb.toString();
134    }
135
136    private static boolean isJmxDisabled() {
137        return PropertiesUtil.getProperties().getBooleanProperty(PROPERTY_DISABLE_JMX);
138    }
139
140    public static void reregisterMBeansAfterReconfigure() {
141        // avoid creating Platform MBean Server if JMX disabled
142        if (isJmxDisabled()) {
143            LOGGER.debug("JMX disabled for log4j2. Not registering MBeans.");
144            return;
145        }
146        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
147        reregisterMBeansAfterReconfigure(mbs);
148    }
149
150    public static void reregisterMBeansAfterReconfigure(final MBeanServer mbs) {
151        if (isJmxDisabled()) {
152            LOGGER.debug("JMX disabled for log4j2. Not registering MBeans.");
153            return;
154        }
155
156        // now provide instrumentation for the newly configured
157        // LoggerConfigs and Appenders
158        try {
159            final ContextSelector selector = getContextSelector();
160            if (selector == null) {
161                LOGGER.debug("Could not register MBeans: no ContextSelector found.");
162                return;
163            }
164            final List<LoggerContext> contexts = selector.getLoggerContexts();
165            for (final LoggerContext ctx : contexts) {
166                // first unregister the context and all nested loggers,
167                // appenders, statusLogger, contextSelector, ringbuffers...
168                unregisterLoggerContext(ctx.getName(), mbs);
169
170                final LoggerContextAdmin mbean = new LoggerContextAdmin(ctx, executor);
171                register(mbs, mbean, mbean.getObjectName());
172
173                if (ctx instanceof AsyncLoggerContext) {
174                    final RingBufferAdmin rbmbean = AsyncLogger.createRingBufferAdmin(ctx.getName());
175                    register(mbs, rbmbean, rbmbean.getObjectName());
176                }
177
178                // register the status logger and the context selector
179                // repeatedly
180                // for each known context: if one context is unregistered,
181                // these MBeans should still be available for the other
182                // contexts.
183                registerStatusLogger(ctx.getName(), mbs, executor);
184                registerContextSelector(ctx.getName(), selector, mbs, executor);
185
186                registerLoggerConfigs(ctx, mbs, executor);
187                registerAppenders(ctx, mbs, executor);
188            }
189        } catch (final Exception ex) {
190            LOGGER.error("Could not register mbeans", ex);
191        }
192    }
193
194    /**
195     * Unregister all log4j MBeans from the platform MBean server.
196     */
197    public static void unregisterMBeans() {
198        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
199        unregisterMBeans(mbs);
200    }
201
202    /**
203     * Unregister all log4j MBeans from the specified MBean server.
204     *
205     * @param mbs the MBean server to unregister from.
206     */
207    public static void unregisterMBeans(final MBeanServer mbs) {
208        unregisterStatusLogger("*", mbs);
209        unregisterContextSelector("*", mbs);
210        unregisterContexts(mbs);
211        unregisterLoggerConfigs("*", mbs);
212        unregisterAsyncLoggerRingBufferAdmins("*", mbs);
213        unregisterAsyncLoggerConfigRingBufferAdmins("*", mbs);
214        unregisterAppenders("*", mbs);
215        unregisterAsyncAppenders("*", mbs);
216    }
217
218    /**
219     * Returns the {@code ContextSelector} of the current {@code Log4jContextFactory}.
220     *
221     * @return the {@code ContextSelector} of the current {@code Log4jContextFactory}
222     */
223    private static ContextSelector getContextSelector() {
224        final LoggerContextFactory factory = LogManager.getFactory();
225        if (factory instanceof Log4jContextFactory) {
226            final ContextSelector selector = ((Log4jContextFactory) factory).getSelector();
227            return selector;
228        }
229        return null;
230    }
231
232    /**
233     * Unregisters all MBeans associated with the specified logger context (including MBeans for {@code LoggerConfig}s
234     * and {@code Appender}s from the platform MBean server.
235     *
236     * @param loggerContextName name of the logger context to unregister
237     */
238    public static void unregisterLoggerContext(final String loggerContextName) {
239        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
240        unregisterLoggerContext(loggerContextName, mbs);
241    }
242
243    /**
244     * Unregisters all MBeans associated with the specified logger context (including MBeans for {@code LoggerConfig}s
245     * and {@code Appender}s from the platform MBean server.
246     *
247     * @param contextName name of the logger context to unregister
248     * @param mbs the MBean Server to unregister the instrumented objects from
249     */
250    public static void unregisterLoggerContext(final String contextName, final MBeanServer mbs) {
251        final String pattern = LoggerContextAdminMBean.PATTERN;
252        final String search = String.format(pattern, escape(contextName), "*");
253        unregisterAllMatching(search, mbs); // unregister context mbean
254
255        // now unregister all MBeans associated with this logger context
256        unregisterStatusLogger(contextName, mbs);
257        unregisterContextSelector(contextName, mbs);
258        unregisterLoggerConfigs(contextName, mbs);
259        unregisterAppenders(contextName, mbs);
260        unregisterAsyncAppenders(contextName, mbs);
261        unregisterAsyncLoggerRingBufferAdmins(contextName, mbs);
262        unregisterAsyncLoggerConfigRingBufferAdmins(contextName, mbs);
263    }
264
265    private static void registerStatusLogger(final String contextName, final MBeanServer mbs, final Executor executor)
266            throws InstanceAlreadyExistsException, MBeanRegistrationException, NotCompliantMBeanException {
267
268        final StatusLoggerAdmin mbean = new StatusLoggerAdmin(contextName, executor);
269        register(mbs, mbean, mbean.getObjectName());
270    }
271
272    private static void registerContextSelector(final String contextName, final ContextSelector selector,
273            final MBeanServer mbs, final Executor executor) throws InstanceAlreadyExistsException,
274            MBeanRegistrationException, NotCompliantMBeanException {
275
276        final ContextSelectorAdmin mbean = new ContextSelectorAdmin(contextName, selector);
277        register(mbs, mbean, mbean.getObjectName());
278    }
279
280    private static void unregisterStatusLogger(final String contextName, final MBeanServer mbs) {
281        final String pattern = StatusLoggerAdminMBean.PATTERN;
282        final String search = String.format(pattern, escape(contextName), "*");
283        unregisterAllMatching(search, mbs);
284    }
285
286    private static void unregisterContextSelector(final String contextName, final MBeanServer mbs) {
287        final String pattern = ContextSelectorAdminMBean.PATTERN;
288        final String search = String.format(pattern, escape(contextName), "*");
289        unregisterAllMatching(search, mbs);
290    }
291
292    private static void unregisterLoggerConfigs(final String contextName, final MBeanServer mbs) {
293        final String pattern = LoggerConfigAdminMBean.PATTERN;
294        final String search = String.format(pattern, escape(contextName), "*");
295        unregisterAllMatching(search, mbs);
296    }
297
298    private static void unregisterContexts(final MBeanServer mbs) {
299        final String pattern = LoggerContextAdminMBean.PATTERN;
300        final String search = String.format(pattern, "*");
301        unregisterAllMatching(search, mbs);
302    }
303
304    private static void unregisterAppenders(final String contextName, final MBeanServer mbs) {
305        final String pattern = AppenderAdminMBean.PATTERN;
306        final String search = String.format(pattern, escape(contextName), "*");
307        unregisterAllMatching(search, mbs);
308    }
309
310    private static void unregisterAsyncAppenders(final String contextName, final MBeanServer mbs) {
311        final String pattern = AsyncAppenderAdminMBean.PATTERN;
312        final String search = String.format(pattern, escape(contextName), "*");
313        unregisterAllMatching(search, mbs);
314    }
315
316    private static void unregisterAsyncLoggerRingBufferAdmins(final String contextName, final MBeanServer mbs) {
317        final String pattern1 = RingBufferAdminMBean.PATTERN_ASYNC_LOGGER;
318        final String search1 = String.format(pattern1, escape(contextName));
319        unregisterAllMatching(search1, mbs);
320    }
321
322    private static void unregisterAsyncLoggerConfigRingBufferAdmins(final String contextName, final MBeanServer mbs) {
323        final String pattern2 = RingBufferAdminMBean.PATTERN_ASYNC_LOGGER_CONFIG;
324        final String search2 = String.format(pattern2, escape(contextName), "*");
325        unregisterAllMatching(search2, mbs);
326    }
327
328    private static void unregisterAllMatching(final String search, final MBeanServer mbs) {
329        try {
330            final ObjectName pattern = new ObjectName(search);
331            final Set<ObjectName> found = mbs.queryNames(pattern, null);
332            for (final ObjectName objectName : found) {
333                LOGGER.debug("Unregistering MBean {}", objectName);
334                mbs.unregisterMBean(objectName);
335            }
336        } catch (final Exception ex) {
337            LOGGER.error("Could not unregister MBeans for " + search, ex);
338        }
339    }
340
341    private static void registerLoggerConfigs(final LoggerContext ctx, final MBeanServer mbs, final Executor executor)
342            throws InstanceAlreadyExistsException, MBeanRegistrationException, NotCompliantMBeanException {
343
344        final Map<String, LoggerConfig> map = ctx.getConfiguration().getLoggers();
345        for (final String name : map.keySet()) {
346            final LoggerConfig cfg = map.get(name);
347            final LoggerConfigAdmin mbean = new LoggerConfigAdmin(ctx, cfg);
348            register(mbs, mbean, mbean.getObjectName());
349
350            if (cfg instanceof AsyncLoggerConfig) {
351                final AsyncLoggerConfig async = (AsyncLoggerConfig) cfg;
352                final RingBufferAdmin rbmbean = async.createRingBufferAdmin(ctx.getName());
353                register(mbs, rbmbean, rbmbean.getObjectName());
354            }
355        }
356    }
357
358    private static void registerAppenders(final LoggerContext ctx, final MBeanServer mbs, final Executor executor)
359            throws InstanceAlreadyExistsException, MBeanRegistrationException, NotCompliantMBeanException {
360
361        final Map<String, Appender> map = ctx.getConfiguration().getAppenders();
362        for (final String name : map.keySet()) {
363            final Appender appender = map.get(name);
364
365            if (appender instanceof AsyncAppender) {
366                final AsyncAppender async = ((AsyncAppender) appender);
367                final AsyncAppenderAdmin mbean = new AsyncAppenderAdmin(ctx.getName(), async);
368                register(mbs, mbean, mbean.getObjectName());
369            } else {
370                final AppenderAdmin mbean = new AppenderAdmin(ctx.getName(), appender);
371                register(mbs, mbean, mbean.getObjectName());
372            }
373        }
374    }
375
376    private static void register(final MBeanServer mbs, final Object mbean, final ObjectName objectName)
377            throws InstanceAlreadyExistsException, MBeanRegistrationException, NotCompliantMBeanException {
378        LOGGER.debug("Registering MBean {}", objectName);
379        mbs.registerMBean(mbean, objectName);
380    }
381}