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.appender.rolling;
018
019import java.lang.reflect.Method;
020
021import org.apache.logging.log4j.core.LogEvent;
022import org.apache.logging.log4j.core.config.plugins.Plugin;
023import org.apache.logging.log4j.core.config.plugins.PluginFactory;
024import org.apache.logging.log4j.core.util.Loader;
025import 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)
033public 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}