I am trying to use Log4J2 logging as described here in the AWS docs:
https://docs.aws.amazon.com/lambda/latest/dg/java-logging.html#java-wt-logging-using-log4j2.8
<?xml version="1.0" encoding="UTF-8"?>
<Configuration packages="com.amazonaws.services.lambda.runtime.log4j2.LambdaAppender">
<Appenders>
<Lambda name="Lambda">
<PatternLayout>
<pattern>%d{yyyy-MM-dd HH:mm:ss} %X{AWSRequestId} %-5p %c{1}:%L - %m%n</pattern>
</PatternLayout>
</Lambda>
</Appenders>
<Loggers>
<Root level="debug">
<AppenderRef ref="Lambda" />
</Root>
</Loggers>
</Configuration>
Error However I am getting the following error when running the lambda: (I removed timestamps below to improve readability)
ERROR Error processing element Lambda ([Appenders: null]): CLASS_NOT_FOUND
ERROR Unable to locate appender "Lambda" for logger config "root"
Tried
I made sure that the log4J libs and log4j-core, log4j-api, aws-lambda-java-log4j2 and aws-lamda-java-core are all in the package.
I also had this problem. It turns out that there is a typo bug in the AWS example documentation.
The packages in the <Configuration .. tag is wrong.
According to the log4j plugin configuration docs the packages parameter is a package not a class.
So modify your log4j2.xml configuration to be...
<?xml version="1.0" encoding="UTF-8"?>
<Configuration packages="com.amazonaws.services.lambda.runtime.log4j2">
<Appenders>
<Lambda name="Lambda">
<PatternLayout>
<pattern>%d{yyyy-MM-dd HH:mm:ss} %X{AWSRequestId} %-5p %c{1}:%L - %m%n</pattern>
</PatternLayout>
</Lambda>
</Appenders>
<Loggers>
<Root level="debug">
<AppenderRef ref="Lambda" />
</Root>
</Loggers>
</Configuration>
Hope this helps. Cheers