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.TimeUnit; 022import java.util.concurrent.atomic.AtomicBoolean; 023import java.util.concurrent.atomic.AtomicInteger; 024import java.util.concurrent.locks.Condition; 025import java.util.concurrent.locks.Lock; 026import java.util.concurrent.locks.ReentrantLock; 027 028import org.apache.logging.log4j.Level; 029import org.apache.logging.log4j.Marker; 030import org.apache.logging.log4j.core.LogEvent; 031import org.apache.logging.log4j.message.Message; 032import org.apache.logging.log4j.util.Supplier; 033 034/** 035 * ReliabilityStrategy that counts the number of threads that have started to log an event but have not completed yet, 036 * and waits for these threads to finish before allowing the appenders to be stopped. 037 */ 038public class AwaitCompletionReliabilityStrategy implements ReliabilityStrategy { 039 private static final int MAX_RETRIES = 3; 040 private final AtomicInteger counter = new AtomicInteger(); 041 private final AtomicBoolean shutdown = new AtomicBoolean(false); 042 private final Lock shutdownLock = new ReentrantLock(); 043 private final Condition noLogEvents = shutdownLock.newCondition(); // should only be used when shutdown == true 044 private final LoggerConfig loggerConfig; 045 046 public AwaitCompletionReliabilityStrategy(final LoggerConfig loggerConfig) { 047 this.loggerConfig = Objects.requireNonNull(loggerConfig, "loggerConfig is null"); 048 } 049 050 /* 051 * (non-Javadoc) 052 * 053 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier, 054 * java.lang.String, java.lang.String, org.apache.logging.log4j.Marker, org.apache.logging.log4j.Level, 055 * org.apache.logging.log4j.message.Message, java.lang.Throwable) 056 */ 057 @Override 058 public void log(final Supplier<LoggerConfig> reconfigured, final String loggerName, final String fqcn, 059 final Marker marker, final Level level, final Message data, final Throwable t) { 060 061 final LoggerConfig config = getActiveLoggerConfig(reconfigured); 062 try { 063 config.log(loggerName, fqcn, marker, level, data, t); 064 } finally { 065 config.getReliabilityStrategy().afterLogEvent(); 066 } 067 } 068 069 /* 070 * (non-Javadoc) 071 * 072 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier, 073 * org.apache.logging.log4j.core.LogEvent) 074 */ 075 @Override 076 public void log(final Supplier<LoggerConfig> reconfigured, final LogEvent event) { 077 final LoggerConfig config = getActiveLoggerConfig(reconfigured); 078 try { 079 config.log(event); 080 } finally { 081 config.getReliabilityStrategy().afterLogEvent(); 082 } 083 } 084 085 /* 086 * (non-Javadoc) 087 * 088 * @see 089 * org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeLogEvent(org.apache.logging.log4j.core.config. 090 * LoggerConfig, org.apache.logging.log4j.util.Supplier) 091 */ 092 @Override 093 public LoggerConfig getActiveLoggerConfig(final Supplier<LoggerConfig> next) { 094 LoggerConfig result = this.loggerConfig; 095 if (!beforeLogEvent()) { 096 result = next.get(); 097 return result.getReliabilityStrategy().getActiveLoggerConfig(next); 098 } 099 return result; 100 } 101 102 private boolean beforeLogEvent() { 103 return counter.incrementAndGet() > 0; 104 } 105 106 public void afterLogEvent() { 107 if (counter.decrementAndGet() == 0 && shutdown.get()) { 108 signalCompletionIfShutdown(); 109 } 110 } 111 112 private void signalCompletionIfShutdown() { 113 final Lock lock = shutdownLock; 114 lock.lock(); 115 try { 116 noLogEvents.signalAll(); 117 } finally { 118 lock.unlock(); 119 } 120 } 121 122 /* 123 * (non-Javadoc) 124 * 125 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopAppenders() 126 */ 127 @Override 128 public void beforeStopAppenders() { 129 waitForCompletion(); 130 } 131 132 /** 133 * Waits for all log events to complete before returning. 134 */ 135 private void waitForCompletion() { 136 shutdownLock.lock(); 137 try { 138 if (shutdown.compareAndSet(false, true)) { 139 int retries = 0; 140 // repeat while counter is non-zero 141 while (!counter.compareAndSet(0, Integer.MIN_VALUE)) { 142 143 // counter was non-zero 144 if (counter.get() < 0) { // this should not happen 145 return; // but if it does, we are already done 146 } 147 // counter greater than zero, wait for afterLogEvent to decrease count 148 try { 149 noLogEvents.await(retries + 1, TimeUnit.SECONDS); 150 } catch (final InterruptedException ie) { 151 if (++retries > MAX_RETRIES) { 152 break; 153 } 154 } 155 } 156 } 157 } finally { 158 shutdownLock.unlock(); 159 } 160 } 161 162 /* 163 * (non-Javadoc) 164 * 165 * @see 166 * org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopConfiguration(org.apache.logging.log4j.core 167 * .config.Configuration) 168 */ 169 @Override 170 public void beforeStopConfiguration(Configuration configuration) { 171 // no action 172 } 173 174}