This appender for Apache Log4j 2 logs messages to a GELF server like Graylog2 or logstash.

It's using the official GELF Java client to connect to a remote server.

You can specify the following parameters for the GELF appender in the log4j2.xml configuration file:

• name
  • The reference name of the Appender
• server (default: localhost)
  • The host name or IP address of the GELF server
• port (default: 12201)
  • The port the GELF server is listening on
• hostName (default: the local host name or localhost if it couldn't be detected)
  • The host name of the machine generating the logs
• protocol (default: UDP)
  • The transport protocol to use
• includeSource (default: true)
  • Whether the source of the log message should be included
• includeThreadContext (default: true)
  • Whether the contents of the ThreadContext should be included
• includeStackTrace (default: true)
  • Whether a full stack trace should be included
• queueSize (default: 512)
  • The size of the internally used queue
• connectTimeout (default: 1000)
  • The connection timeout for TCP connections in milliseconds
• reconnectDelay (default: 500)
  • The time to wait between reconnects in milliseconds
• sendBufferSize (default: -1)
  • The size of the socket send buffer in bytes. A size of -1 deactivates the send buffer
• tcpNoDelay (default: false)
  • Whether Nagle's algorithm should be used for TCP connections
• filter
  • A Filter to determine if the event should be handled by this Appender
• layout (default: "%m%n")
  • The Layout to use to format the LogEvent
• ignoreExceptions
  • The default is true, causing exceptions encountered while appending events to be internally logged and then ignored. When set to false exceptions will be propagated to the caller, instead. Must be set to false when wrapping this Appender in a FailoverAppender.
• additionalFields
  • Comma-delimited list of key=value pairs to be included in every message

<configuration status="OFF" packages="org.graylog2.log4j2">
    <appenders>
        <GELF name="gelfAppender" server="graylog2.example.com" port="12201" hostName="appserver01.example.com" additionalFields="foo=bar"/>
    </appenders>
    <loggers>
        <root level="info">
            <appender-ref ref="gelfAppender"/>
        </root>
    </loggers>
</configuration>

Logger logger = LogManager.getLogger("test");
ThreadContext.put("userId", "testUser");
logger.info("Hello World");

This appender uses GELF Java client 1.1.0.

Maven coordinates

<dependencies>
    <dependency>
        <groupId>org.graylog2.log4j2</groupId>
        <artifactId>log4j2-gelf</artifactId>
        <version>1.0.3</version>
    </dependency>
</dependencies>

GELF Appender for Apache Log4j 2

Copyright (C) 2014 TORCH GmbH

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.