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 /* (non-Javadoc) 051 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier, java.lang.String, java.lang.String, org.apache.logging.log4j.Marker, org.apache.logging.log4j.Level, org.apache.logging.log4j.message.Message, java.lang.Throwable) 052 */ 053 @Override 054 public void log(final Supplier<LoggerConfig> reconfigured, final String loggerName, final String fqcn, 055 final Marker marker, final Level level, final Message data, final Throwable t) { 056 057 final LoggerConfig config = getActiveLoggerConfig(reconfigured); 058 try { 059 config.log(loggerName, fqcn, marker, level, data, t); 060 } finally { 061 config.getReliabilityStrategy().afterLogEvent(); 062 } 063 } 064 065 /* (non-Javadoc) 066 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#log(org.apache.logging.log4j.util.Supplier, org.apache.logging.log4j.core.LogEvent) 067 */ 068 @Override 069 public void log(final Supplier<LoggerConfig> reconfigured, final LogEvent event) { 070 final LoggerConfig config = getActiveLoggerConfig(reconfigured); 071 try { 072 config.log(event); 073 } finally { 074 config.getReliabilityStrategy().afterLogEvent(); 075 } 076 } 077 078 /* (non-Javadoc) 079 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeLogEvent(org.apache.logging.log4j.core.config.LoggerConfig, org.apache.logging.log4j.util.Supplier) 080 */ 081 @Override 082 public LoggerConfig getActiveLoggerConfig(final Supplier<LoggerConfig> next) { 083 LoggerConfig result = this.loggerConfig; 084 if (!beforeLogEvent()) { 085 result = next.get(); 086 return result.getReliabilityStrategy().getActiveLoggerConfig(next); 087 } 088 return result; 089 } 090 091 private boolean beforeLogEvent() { 092 return counter.incrementAndGet() > 0; 093 } 094 095 public void afterLogEvent() { 096 if (counter.decrementAndGet() == 0 && shutdown.get()) { 097 signalCompletionIfShutdown(); 098 } 099 } 100 101 private void signalCompletionIfShutdown() { 102 final Lock lock = shutdownLock; 103 lock.lock(); 104 try { 105 noLogEvents.signalAll(); 106 } finally { 107 lock.unlock(); 108 } 109 } 110 111 /* (non-Javadoc) 112 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopAppenders() 113 */ 114 @Override 115 public void beforeStopAppenders() { 116 waitForCompletion(); 117 } 118 119 /** 120 * Waits for all log events to complete before returning. 121 */ 122 private void waitForCompletion() { 123 shutdownLock.lock(); 124 try { 125 if (shutdown.compareAndSet(false, true)) { 126 int retries = 0; 127 // repeat while counter is non-zero 128 while (!counter.compareAndSet(0, Integer.MIN_VALUE)) { 129 130 // counter was non-zero 131 if (counter.get() < 0) { // this should not happen 132 return; // but if it does, we are already done 133 } 134 // counter greater than zero, wait for afterLogEvent to decrease count 135 try { 136 noLogEvents.await(retries + 1, TimeUnit.SECONDS); 137 } catch (final InterruptedException ie) { 138 if (++retries > MAX_RETRIES) { 139 break; 140 } 141 } 142 } 143 } 144 } finally { 145 shutdownLock.unlock(); 146 } 147 } 148 149 /* (non-Javadoc) 150 * @see org.apache.logging.log4j.core.config.ReliabilityStrategy#beforeStopConfiguration(org.apache.logging.log4j.core.config.Configuration) 151 */ 152 @Override 153 public void beforeStopConfiguration(Configuration configuration) { 154 // no action 155 } 156 157}