自定义 appender 的 log4j2 属性文件

Question

I created a custom appender and it's not getting called when I run my test. Here's what the properties look like:

name=config
appenders=console, myCustomAppender

appender.console.type=Console
appender.console.name=STDOUT
appender.console.layout.type=PatternLayout
#appender.console.layout.pattern =%d{HH:mm:ss} [%t] %c{1} [%-5level] - %msg%n
appender.console.layout.pattern=%d{dd-MM-yyyy HH:mm:ss} [%-5p] (%F:%L) - %m%n

appender.myCustomAppender = com.myCompany.logging.log4j.WindowsEventLogAppender
appender.myCustomAppender.name = WindowsEventLogAppender
appender.myCustomAppender.type = WindowsEventLogAppender

rootLogger.level=info
rootLogger.appenderRefs=stdout, myCustomAppender
rootLogger.appenderRef.stdout.ref=STDOUT

My appender is called a WindowsEventLogAppender. Any idea what's wrong with my properties file? I see the console test messages but none of the messages from my appender. Right now I'm just doing a System.out.println in my custom appender to verify it's getting called.

BTW, I've found lot's of XML examples out there for log4j2 configurations with custom appenders but none for using a properties file for configuration.

Thanks, -Mike

Answer 1

I might be quite late here, but I think my answer can help other people looking for answers. Please accept this as an answer if this is correct!

If you have created a custom appender having annotation like this:

@Plugin(name = "MyCustomAppender", category = "Core", 
elementType = "appender", printObject = true)
public final class MyCustomAppenderImpl extends AbstractAppender {
  // other code for the plugin....
}

The log4j2 manual about Configuring Appenders states that:

"An appender is configured either using the specific appender plugin's name or with an appender element and the type attribute containing the appender plugin's name"

Meaning the type for appender should be Appender Plugin's Name attribute value.

Which in above case is MyCustomAppender ( appender.identifierName.type=MyCustomAppender )

So, the Properties file configuration for this to work should be:

(Note : I have added a stdout(console) appender just to show relevance/similarity of usage with OOTB appenders, and 2 example usages with RootLogger and a custom logger)

# this packages attribute is important, please put comma seperated package(s) to the 
# plugin(s) you have created
packages = com.package.to.your.plugin

# Example: Declare and Define OOTB Console appender, which sends log events to stdout
appender.console.name = stdout
appender.console.type = Console

# Declare and define the custom appender like this
# Note that the "abc" in "appender.abc.type" can be anything
# and the value for "appender.abc.type" should be the same as 
# "Name" attribute value given in custom appender plugin which is "MyCustomAppender"
appender.abc.name=arbitrary_name
appender.abc.type=MyCustomAppender

rootLogger.appenderRef.stdout.ref = stdout
rootLogger.appenderRef.abc.ref = arbitrary_name    

logger.loggeridentifier.name = com.test.SomeClass
logger.loggeridentifier.appenderRef.stdout.ref = stdout
logger.loggeridentifier.appenderRef.abc.ref = arbitrary_name

# Also note that the value of appenderRef should be the same name given to your 
# appender in properties file, which in this case is "arbitrary_name" (as given above)

Answer 2

Try adding the packages property.

Like: packages = com.myCompany

Answer 3

You haven't included the package info

try the below configuration.

name=config
appenders=console, myCustomAppender
appender.console.type=Console
appender.console.name=STDOUT
appender.console.layout.type=PatternLayout
#appender.console.layout.pattern =%d{HH:mm:ss} [%t] %c{1} [%-5level] - %msg%n
appender.console.layout.pattern=%d{dd-MM-yyyy HH:mm:ss} [%-5p] (%F:%L) - %m%n
appender.myCustomAppender = com.myCompany.logging.log4j.WindowsEventLogAppender
appender.myCustomAppender.name = WindowsEventLogAppender
appender.myCustomAppender.type = WindowsEventLogAppender
rootLogger.level=info
rootLogger.appenderRefs=stdout, myCustomAppender
rootLogger.appenderRef.stdout.ref=STDOUT
rootLogger.com.mycompany.example=INFO,STDOUT