log4j 1.2.x JSON Layout

Following settings can be used:

Attribute Name	Description	Default
lineBreak	End of line string	platform dependent default value, see `System.getProperty("line.separator")`
fields	Comma-separated list of log event fields that should be included in the JSON	`Time, Severity, ThreadName, SourceClassName, SourceMethodName, SourceSimpleClassName, LoggerName, NDC, Server`
version	GELF Version `1.0` or `1.1`	`1.0`
originHost	Originating Hostname	FQDN Hostname
extractStackTrace	Send the Stack-Trace to the StackTrace field (`true`/`false`)	`false`
filterStackTrace	Perform Stack-Trace filtering (`true`/`false`)	`false`
includeLocation	Include source code location	`true`
mdcProfiling	Perform Profiling (Call-Duration) based on MDC Data. See MDC Profiling for details	`false`
facility	Name of the Facility	`logstash-gelf`
additionalFields	Send additional static fields. The fields are specified as key-value pairs are comma-separated. Example: `GelfLogHandler.additionalFields=fieldName=Value,fieldName2=Value2`	none
additionalFieldTypes	Type specification for additional and MDC fields. Supported types: `String`, `long`, `Long`, `double`, `Double` and `discover` (default if not specified, discover field type on parseability). Eg. field=String,field2=double	`discover` for all additional fields
mdcFields	Send additional fields whose values are obtained from MDC. Name of the Fields are comma-separated. Example: `mdcFields=Application,Version,SomeOtherFieldName`	none
dynamicMdcFields	Dynamic MDC Fields allows you to extract MDC values based on one or more regular expressions. Multiple regexes are comma-separated. The name of the MDC entry is used as GELF field name.	none
dynamicMdcFieldTypes	Pattern-based type specification for additional and MDC fields. Key-value pairs are comma-separated. Example: `my_field.=String,business\..\.field=double`	none
includeFullMdc	Include all fields from the MDC.	`false`
timestampPattern	Date/time pattern for the `Time` field	`yyyy-MM-dd HH:mm:ss,SSS`

The JSON formatter creates then messages like:

{
    "LoggerName": "org.wildfly.extension.undertow",
    "short_message": "WFLYUT0008: Undertow HTTP listener default suspending",
    "level": "6",
    "Time": "2015-08-11 21:25:32,0734",
    "Severity": "INFO",
    "MessageParam1": "default",
    "Thread": "MSC service thread 1-6",
    "SourceMethodName": "stopListening",
    "MessageParam0": "HTTP",
    "full_message": "WFLYUT0008: Undertow HTTP listener default suspending",
    "SourceSimpleClassName": "HttpListenerService",
    "SourceClassName": "org.wildfly.extension.undertow.HttpListenerService",
    "facility": "logstash-gelf",
    "timestamp": "1439321132.734"
}

Default line break depends on the platform, JSON objects are separated by line breaks only.

log4j Configuration

Properties:

log4j.appender.file.layout=biz.paluch.logging.gelf.log4j.GelfLayout
log4j.appender.file.layout.Version=1.0
log4j.appender.file.layout.Facility=logstash-gelf
log4j.appender.file.layout.ExtractStackTrace=true
log4j.appender.file.layout.FilterStackTrace=true
log4j.appender.file.layout.IncludeLocation=true
log4j.appender.file.layout.MdcProfiling=true
log4j.appender.file.layout.TimestampPattern=yyyy-MM-dd HH:mm:ss,SSS
log4j.appender.file.layout.AdditionalFields=fieldName1=fieldValue1,fieldName2=fieldValue2
log4j.appender.file.layout.AdditionalFieldTypes=fieldName1=String,fieldName2=Double,fieldName3=Long
log4j.appender.file.layout.MdcFields=mdcField1,mdcField2
log4j.appender.file.layout.DynamicMdcFields=mdc.*,(mdc|MDC)fields
log4j.appender.file.layout.DynamicMdcFieldTypes=my_field.*=String,business\..*\.field=double
log4j.appender.file.layout.IncludeFullMdc=true

XML:

<appender name="file" class="org.apache.log4j.FileAppender">
    <param name="file" value="logfile.log" />
    <layout class="biz.paluch.logging.gelf.log4j.GelfLayout">
        <param name="Facility" value="logstash-gelf" />
        <param name="ExtractStackTrace" value="true" />
        <param name="FilterStackTrace" value="true" />
        <param name="MdcProfiling" value="true" />
        <param name="IncludeLocation" value="true" />
        <param name="TimestampPattern" value="yyyy-MM-dd HH:mm:ss,SSS" />
        <param name="AdditionalFields" value="fieldName1=fieldValue1,fieldName2=fieldValue2" />
        <param name="AdditionalFieldTypes" value="fieldName1=String,fieldName2=Double,fieldName3=Long" />
        <param name="MdcFields" value="mdcField1,mdcField2" />
        <param name="DynamicMdcFields" value="mdc.*,(mdc|MDC)fields" />
        <param name="DynamicMdcFieldTypes" value="my_field.*=String,business\..*\.field=double" />
        <param name="IncludeFullMdc" value="true" />
    </layout>
</appender>