How to set Java agent log level for specific classes?

[mfridljand]

How to set the log level for Java agent classes?

There are JVM parameters to specify Java agent external log file and to set the default log level

-Dio.opentelemetry.javaagent.slf4j.simpleLogger.logFile=<…/otel_agent.log>
-Dio.opentelemetry.javaagent.slf4j.simpleLogger.defaultLogLevel=DEBUG 

But how to set the log level for individual classes, to allow or to suppress logging for specific classes?
I tried to configure JVM parameters like

-Dio.opentelemetry.javaagent.slf4j.simpleLogger.io.opentelemetry.exporter.logging.LoggingSpanExporter=WARN
-Dio.opentelemetry.javaagent.slf4j.simpleLogger.io.opentelemetry.javaagent.shaded.instrumentation.jmx.internal.engine.BeanAttributeExtractor=INFO

or to specify a simplelogger.properties file via
-Djava.util.logging.config.file=<….>/simplelogger.properties
but it does not seem to work.

It might be a general java.util.logging question … but I have had no success with any configuration so far.

Thanks,
Best regards,
Mihail

[laurit]

It might be a general java.util.logging question … but I have had no success with any configuration so far.

Agent uses slf4j simple logger not java util logging. See https://www.slf4j.org/api/org/slf4j/simple/SimpleLogger.html for configuration options. As you have already noticed simple logger is shaded into a different package so the configuration options will need to be adjusted accordingly. Here is an example -Dio.opentelemetry.javaagent.slf4j.simpleLogger.log.io.opentelemetry.sdk.metrics.export.PeriodicMetricReader=INFO

[mfridljand]

Ah, I missed this .log before the class name. Thank you!

For every instrumentation module loaded the agent writes out a corresponding log message:
DEBUG io.opentelemetry.javaagent.tooling.instrumentation.InstrumentationLoader - Loading instrumentation java-http-client [class io.opentelemetry.javaagent.instrumentation.javahttpclient.HttpClientInstrumentationModule]

But it does not do so for extensions, does it?!

[laurit]

But it does not do so for extensions, does it?!

I don't know. If you didn't see anything in the log then it doesn't. Though if you have an instrumentation module inside your extension then the you should see the line from InstrumentationLoader for your instrumentation module.

[mfridljand]

Well, I can confirm if everything works the InstrumentationLoader writes out a "Loading instrumentation ... " message for evry loaded instrumentation module to the log file. One of older log files has it. Thus, something else must be wrong now :(