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    package org.apache.logging.log4j.core.appender.rolling;
018    
019    import java.lang.reflect.Method;
020    
021    import org.apache.logging.log4j.core.LogEvent;
022    import org.apache.logging.log4j.core.config.plugins.Plugin;
023    import org.apache.logging.log4j.core.config.plugins.PluginFactory;
024    import org.apache.logging.log4j.core.util.Loader;
025    import org.apache.logging.log4j.status.StatusLogger;
026    
027    /**
028     * Triggers a rollover on every restart. The target file's timestamp is compared with the JVM start time
029     * and if it is older isTriggeringEvent will return true. After isTriggeringEvent has been called it will
030     * always return false.
031     */
032    @Plugin(name = "OnStartupTriggeringPolicy", category = "Core", printObject = true)
033    public class OnStartupTriggeringPolicy implements TriggeringPolicy {
034        private static long JVM_START_TIME = initStartTime();
035    
036        private boolean evaluated = false;
037        private RollingFileManager manager;
038    
039        /**
040         * Provide the RollingFileManager to the policy.
041         * @param manager The RollingFileManager.
042         */
043        @Override
044        public void initialize(final RollingFileManager manager) {
045            this.manager = manager;
046            if (JVM_START_TIME == 0) {
047                evaluated = true;
048            }
049        }
050    
051        /**
052         * Returns the result of {@code ManagementFactory.getRuntimeMXBean().getStartTime()},
053         * or the current system time if JMX is not available.
054         */
055        private static long initStartTime() {
056            // LOG4J2-379:
057            // We'd like to call ManagementFactory.getRuntimeMXBean().getStartTime(),
058            // but Google App Engine throws a java.lang.NoClassDefFoundError
059            // "java.lang.management.ManagementFactory is a restricted class".
060            // The reflection is necessary because without it, Google App Engine
061            // will refuse to initialize this class.
062            try {
063                final Class<?> factoryClass = Loader.loadSystemClass("java.lang.management.ManagementFactory");
064                final Method getRuntimeMXBean = factoryClass.getMethod("getRuntimeMXBean");
065                final Object runtimeMXBean = getRuntimeMXBean.invoke(null);
066                
067                final Class<?> runtimeMXBeanClass = Loader.loadSystemClass("java.lang.management.RuntimeMXBean");
068                final Method getStartTime = runtimeMXBeanClass.getMethod("getStartTime");
069                final Long result = (Long) getStartTime.invoke(runtimeMXBean);
070    
071                return result.longValue();
072            } catch (final Throwable t) {
073                StatusLogger.getLogger().error("Unable to call ManagementFactory.getRuntimeMXBean().getStartTime(), " //
074                        + "using system time for OnStartupTriggeringPolicy", t);
075                // We have little option but to declare "now" as the beginning of time.
076                return System.currentTimeMillis();
077            }
078        }
079    
080        /**
081         * Determine if a rollover should be triggered.
082         * @param event   A reference to the current event.
083         * @return true if the target file's timestamp is older than the JVM start time.
084         */
085        @Override
086        public boolean isTriggeringEvent(final LogEvent event) {
087            if (evaluated) {
088                return false;
089            }
090            evaluated = true;
091            return manager.getFileTime() < JVM_START_TIME;
092        }
093    
094        @Override
095        public String toString() {
096            return "OnStartupTriggeringPolicy";
097        }
098    
099        @PluginFactory
100        public static OnStartupTriggeringPolicy createPolicy() {
101            return new OnStartupTriggeringPolicy();
102        }
103    }