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.appender.mom.kafka; 019 020import java.io.Serializable; 021import java.nio.charset.StandardCharsets; 022 023import org.apache.logging.log4j.core.Filter; 024import org.apache.logging.log4j.core.Layout; 025import org.apache.logging.log4j.core.LogEvent; 026import org.apache.logging.log4j.core.appender.AbstractAppender; 027import org.apache.logging.log4j.core.appender.AppenderLoggingException; 028import org.apache.logging.log4j.core.config.Property; 029import org.apache.logging.log4j.core.config.plugins.Plugin; 030import org.apache.logging.log4j.core.config.plugins.PluginAttribute; 031import org.apache.logging.log4j.core.config.plugins.PluginElement; 032import org.apache.logging.log4j.core.config.plugins.PluginFactory; 033import org.apache.logging.log4j.core.config.plugins.validation.constraints.Required; 034 035/** 036 * Sends log events to an Apache Kafka topic. 037 */ 038@Plugin(name = "Kafka", category = "Core", elementType = "appender", printObject = true) 039public final class KafkaAppender extends AbstractAppender { 040 041 /** 042 * 043 */ 044 private static final long serialVersionUID = 1L; 045 @PluginFactory 046 public static KafkaAppender createAppender( 047 @PluginElement("Layout") final Layout<? extends Serializable> layout, 048 @PluginElement("Filter") final Filter filter, 049 @Required(message = "No name provided for KafkaAppender") @PluginAttribute("name") final String name, 050 @PluginAttribute(value = "ignoreExceptions", defaultBoolean = true) final boolean ignoreExceptions, 051 @Required(message = "No topic provided for KafkaAppender") @PluginAttribute("topic") final String topic, 052 @PluginElement("Properties") final Property[] properties) { 053 final KafkaManager kafkaManager = new KafkaManager(name, topic, properties); 054 return new KafkaAppender(name, layout, filter, ignoreExceptions, kafkaManager); 055 } 056 057 private final KafkaManager manager; 058 059 private KafkaAppender(final String name, final Layout<? extends Serializable> layout, final Filter filter, final boolean ignoreExceptions, final KafkaManager manager) { 060 super(name, filter, layout, ignoreExceptions); 061 this.manager = manager; 062 } 063 064 @Override 065 public void append(final LogEvent event) { 066 if (event.getLoggerName().startsWith("org.apache.kafka")) { 067 LOGGER.warn("Recursive logging from [{}] for appender [{}].", event.getLoggerName(), getName()); 068 } else { 069 try { 070 if (getLayout() != null) { 071 manager.send(getLayout().toByteArray(event)); 072 } else { 073 manager.send(event.getMessage().getFormattedMessage().getBytes(StandardCharsets.UTF_8)); 074 } 075 } catch (final Exception e) { 076 LOGGER.error("Unable to write to Kafka [{}] for appender [{}].", manager.getName(), getName(), e); 077 throw new AppenderLoggingException("Unable to write to Kafka in appender: " + e.getMessage(), e); 078 } 079 } 080 } 081 082 @Override 083 public void start() { 084 super.start(); 085 manager.startup(); 086 } 087 088 @Override 089 public void stop() { 090 super.stop(); 091 manager.release(); 092 } 093 094}