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.async; 018 019import org.apache.logging.log4j.Level; 020import org.apache.logging.log4j.Logger; 021import org.apache.logging.log4j.status.StatusLogger; 022 023import java.util.Objects; 024import java.util.concurrent.atomic.AtomicLong; 025 026/** 027 * Discarding router extends the DefaultAsyncQueueFullPolicy by first verifying if the queue is fuller than the specified 028 * threshold ratio; if this is the case, log events {@linkplain Level#isMoreSpecificThan(Level) more specific} than 029 * the specified threshold level are dropped. If this is not the case, the {@linkplain DefaultAsyncQueueFullPolicy 030 * default routing rules hold. 031 */ 032public class DiscardingAsyncQueueFullPolicy extends DefaultAsyncQueueFullPolicy { 033 private static final Logger LOGGER = StatusLogger.getLogger(); 034 035 private final Level thresholdLevel; 036 private final AtomicLong discardCount = new AtomicLong(); 037 038 /** 039 * Constructs a router that will discard events {@linkplain Level#isLessSpecificThan(Level) equal or less specific} 040 * than the specified threshold level when the queue is full. 041 * 042 * @param thresholdLevel level of events to discard 043 */ 044 public DiscardingAsyncQueueFullPolicy(final Level thresholdLevel) { 045 this.thresholdLevel = Objects.requireNonNull(thresholdLevel, "thresholdLevel"); 046 } 047 048 @Override 049 public EventRoute getRoute(final long backgroundThreadId, final Level level) { 050 if (level.isLessSpecificThan(thresholdLevel)) { 051 if (discardCount.getAndIncrement() == 0) { 052 LOGGER.warn("Async queue is full, discarding event with level {}. " + 053 "This message will only appear once; future events from {} " + 054 "are silently discarded until queue capacity becomes available.", 055 level, thresholdLevel); 056 } 057 return EventRoute.DISCARD; 058 } 059 return super.getRoute(backgroundThreadId, level); 060 } 061 062 public static long getDiscardCount(final AsyncQueueFullPolicy router) { 063 if (router instanceof DiscardingAsyncQueueFullPolicy) { 064 return ((DiscardingAsyncQueueFullPolicy) router).discardCount.get(); 065 } 066 return 0; 067 } 068 069 public Level getThresholdLevel() { 070 return thresholdLevel; 071 } 072}