ggrandes / log4j2-simplejson

Simple JSON Layout for Log4J 2.x, without external dependencies

SimpleJSON for Log4J 2.x

Simple JSON for Log4J 2.x, without external dependencies. Open Source Java project under Apache License v2.0

Current Stable Version is 1.1.1

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DOC

Supported Log4j2 Versions

SimpleJSON	Log4j2
1.0.x	2.6.x / 2.7.x
1.1.x	2.8.x / 2.12.x / 2.17.x

What provides this module?

Layout & PatternConverter

SimpleJSONLayout

Appends a series of JSON events as strings serialized as bytes. This is like JSONLayout but without external dependencies and simplified (compact=true always).

By default, output will be like:

{"layout.version":1,"layout.start":1470563445561,"layout.sequence":1,"timestamp":1470563445639,"thread":"main","threadId":1,"level":"INFO","logger":"org.javastack.log4j.simplejson.sandbox.TestSimpleJson","msg":"Hello world"}
{"layout.version":1,"layout.start":1470563445561,"layout.sequence":2,"timestamp":1470563445639,"thread":"main","threadId":1,"level":"INFO","logger":"org.javastack.log4j.simplejson.sandbox.TestSimpleJson","ndc":["ndc1","ndc2"],"mdc":{"k1":"v1","k2":"v2"},"msg":"Diagnostic context information is wonder"}
{"layout.version":1,"layout.start":1470563445561,"layout.sequence":3,"timestamp":1470563445639,"thread":"main","threadId":1,"level":"INFO","logger":"org.javastack.log4j.simplejson.sandbox.TestSimpleJson","ndc":["ndc1"],"mdc":{"k1":"v1","k2":"v2"},"msg":"log4j2 is wonder"}
{"layout.version":1,"layout.start":1470563445561,"layout.sequence":4,"timestamp":1470563445639,"thread":"main","threadId":1,"level":"INFO","logger":"org.javastack.log4j.simplejson.sandbox.TestSimpleJson","ndc":["ndc1"],"mdc":{"k1":"v1","k2":"v2"},"msg":"Oops!","exception":"java.lang.Exception","cause":"one exception","stacktrace":"java.lang.Exception: one exception\n\tat org.javastack.log4j.simplejson.sandbox.TestSimpleJson.main(TestSimpleJson.java:26) [classes\/:?]\n"}

SimpleJSONLayout Parameters

Parameter Name	Type	Default	Description
charset	String	US-ASCII	The character set to use when converting to a byte array. The value must be a valid Charset.
eventEol	boolean	true	If true, the appender appends an end-of-line after each record. Use with eventEol=true to get one record per line.
complete	boolean	false	If true, the appender includes the JSON header and footer, and comma between records.
properties	boolean	true	If true, the appender includes the thread context map in the generated JSON.
locationInfo	boolean	false	If true, the appender includes the location information in the generated JSON. Generating location information is an expensive operation and may impact performance. Use with caution.
AdditionalField	KeyValuePair[]	none	Additional fields to include in JSON, these Fields come from Lookups

Usage Example of SimpleJSONLayout

log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn" name="XMLConfig"
	packages="org.javastack.log4j.simplejson">

	<Appenders>
		<Console name="console">
			<SimpleJSONLayout properties="false">
			    <!-- Additional Fields -->
				<KeyValuePair key="javaVersion" value="java:version" />
			</SimpleJSONLayout>
		</Console>
	</Appenders>
	<Loggers>
		<Root level="info">
			<AppenderRef ref="console" />
		</Root>
	</Loggers>
</Configuration>

log4j2.properties

status = warn
name = PropertiesConfig
packages = org.javastack.log4j.simplejson

# Console
appender.console.type = Console
appender.console.name = console
appender.console.layout.type = SimpleJSONLayout
appender.console.layout.properties = false
## Additional Fields
appender.console.layout.additionalfield_1.type = KeyValuePair
appender.console.layout.additionalfield_1.key = javaVersion
appender.console.layout.additionalfield_1.value = java:version

rootLogger.level = info
rootLogger.appenderRef.console.ref = console

Output will be:

{"layout.version":1,"layout.start":1470564523434,"layout.sequence":1,"timestamp":1470564523512,"thread":"main","threadId":1,"level":"INFO","logger":"com.acme.TestSimpleJson","javaVersion":"Java version 1.7.0_80","msg":"Hello world"}

SimpleJSONPatternConverter for core PatternLayout

The conversions that are provided with SimpleJSON are:

Conversion Pattern	Description
json{pattern}	Encodes special characters such as '\n' according to JSON-String RFC-7159. A typical usage would encode the message %json{%m}

Usage Example of PatternConverter (%json{pattern})

log4j2.xml

<Configuration status="warn" name="XMLConfig"
	packages="org.javastack.log4j.simplejson">

	<Appenders>
		<Console name="console">
			<PatternLayout
				pattern='{ "msg":"%json{%m}"%notEmpty{, "exception":"%json{%xEx}"} }%n'
				alwaysWriteExceptions="false" />
		</Console>
	</Appenders>
	<Loggers>
		<Root level="info">
			<AppenderRef ref="console" />
		</Root>
	</Loggers>
</Configuration>

log4j2.properties

status = warn
name = PropertiesConfig
packages = org.javastack.log4j.simplejson

# Console
appender.console.type = Console
appender.console.name = console
## Cooked JSON
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = { "msg":"%json{%m}"%notEmpty{, "exception":"%json{%xEx}"} }%n
appender.console.layout.alwaysWriteExceptions = false

rootLogger.level = info
rootLogger.appenderRef.console.ref = console

Output will be:

{ "msg":"Hello world" }
{ "msg":"Oops!", "exception":"java.lang.Exception: one exception\n\tat org.javastack.log4j.simplejson.sandbox.TestSimpleJson.main(TestSimpleJson.java:26) [classes\/:?]\n" }

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MAVEN

Add the dependency to your pom.xml:

<dependency>
    <groupId>org.javastack</groupId>
    <artifactId>log4j2-simplejson</artifactId>
    <version>1.1.1</version>
</dependency>

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Inspired in log4j2-layouts, this code is Java-minimalistic version.