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;
019
020import java.util.Objects;
021import java.util.concurrent.locks.ReadWriteLock;
022import java.util.concurrent.locks.ReentrantReadWriteLock;
023
024import org.apache.logging.log4j.Level;
025import org.apache.logging.log4j.Marker;
026import org.apache.logging.log4j.core.LogEvent;
027import org.apache.logging.log4j.message.Message;
028import org.apache.logging.log4j.util.Supplier;
029
030/**
031 * ReliabilityStrategy that uses read/write locks to prevent the LoggerConfig from stopping while it is in use.
032 */
033public class LockingReliabilityStrategy implements ReliabilityStrategy, LocationAwareReliabilityStrategy {
034    private final LoggerConfig loggerConfig;
035    private final ReadWriteLock reconfigureLock = new ReentrantReadWriteLock();
036    private volatile boolean isStopping;
037
038    public LockingReliabilityStrategy(final LoggerConfig loggerConfig) {
039        this.loggerConfig = Objects.requireNonNull(loggerConfig, "loggerConfig was null");
040    }
041
042    /*
043     * (non-Javadoc)
044     *
045     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier,
046     * java.lang.String, java.lang.String, org.apache.logging.log4j.Marker, org.apache.logging.log4j.Level,
047     * org.apache.logging.log4j.message.Message, java.lang.Throwable)
048     */
049    @Override
050    public void log(final Supplier<LoggerConfig> reconfigured, final String loggerName, final String fqcn,
051            final Marker marker, final Level level, final Message data, final Throwable t) {
052
053        final LoggerConfig config = getActiveLoggerConfig(reconfigured);
054        try {
055            config.log(loggerName, fqcn, marker, level, data, t);
056        } finally {
057            config.getReliabilityStrategy().afterLogEvent();
058        }
059    }
060
061    /*
062     * (non-Javadoc)
063     *
064     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier,
065     * java.lang.String, java.lang.String, java.lang.StackTraceElement, org.apache.logging.log4j.Marker,
066     * org.apache.logging.log4j.Level, org.apache.logging.log4j.message.Message, java.lang.Throwable)
067     */
068    @Override
069    public void log(final Supplier<LoggerConfig> reconfigured, final String loggerName, final String fqcn,
070        final StackTraceElement location, final Marker marker, final Level level, final Message data,
071        final Throwable t) {
072        final LoggerConfig config = getActiveLoggerConfig(reconfigured);
073        try {
074            config.log(loggerName, fqcn, location, marker, level, data, t);
075        } finally {
076            config.getReliabilityStrategy().afterLogEvent();
077        }
078    }
079
080    /*
081     * (non-Javadoc)
082     *
083     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier,
084     * org.apache.logging.log4j.core.LogEvent)
085     */
086    @Override
087    public void log(final Supplier<LoggerConfig> reconfigured, final LogEvent event) {
088        final LoggerConfig config = getActiveLoggerConfig(reconfigured);
089        try {
090            config.log(event);
091        } finally {
092            config.getReliabilityStrategy().afterLogEvent();
093        }
094    }
095
096    /*
097     * (non-Javadoc)
098     *
099     * @see
100     * org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeLogEvent(org.apache.logging.log4j.core.config.
101     * LoggerConfig, org.apache.logging.log4j.util.Supplier)
102     */
103    @Override
104    public LoggerConfig getActiveLoggerConfig(final Supplier<LoggerConfig> next) {
105        LoggerConfig result = this.loggerConfig;
106        if (!beforeLogEvent()) {
107            result = next.get();
108            return result == this.loggerConfig ? result : result.getReliabilityStrategy().getActiveLoggerConfig(next);
109        }
110        return result;
111    }
112
113    private boolean beforeLogEvent() {
114        reconfigureLock.readLock().lock();
115        if (isStopping) {
116            reconfigureLock.readLock().unlock();
117            return false;
118        }
119        return true;
120    }
121
122    @Override
123    public void afterLogEvent() {
124        reconfigureLock.readLock().unlock();
125    }
126
127    /*
128     * (non-Javadoc)
129     *
130     * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopAppenders()
131     */
132    @Override
133    public void beforeStopAppenders() {
134        reconfigureLock.writeLock().lock();
135        try {
136            isStopping = true;
137        } finally {
138            reconfigureLock.writeLock().unlock();
139        }
140    }
141
142    /*
143     * (non-Javadoc)
144     *
145     * @see
146     * org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopConfiguration(org.apache.logging.log4j.core
147     * .config.Configuration)
148     */
149    @Override
150    public void beforeStopConfiguration(final Configuration configuration) {
151        // no action
152    }
153
154}