Serverside logging of Tomcat ClientAbortException (java.io.IOException)

[Blama]

Hi Isomorphic,

we currently have the problem that our logs are getting cluttered with ERRORS of org.apache.catalina.connector.ClientAbortException (extends java.io.IOException) logged by you (v12.0p_2020-05-03).
These exceptions aren't really bad things where we could or want to do something about (e.g. a user closed a browser window), but we can't ignore them because we can't target them explicitly in our log4j2 config.

It looks like this:


The message itself gets logged in BaseFilter.handleError(HttpServletResponse response, String errorMessage, Throwable t).
While I think it is correct that it gets logged the problem here is that to us all these messages look the same - they just say "BaseServlet Global Exception" with no mention of the root cause ("java.io.IOException: Connection reset by peer").
So in our log4j config we can only ignore all CompressionFilter-logs completely (via log4j-RegexFilter) or have them all, as the message "BaseServlet Global Exception" is always the same.

My question is now if you could either:

• Don't log but rethrow the exception (most likely a big change you don't want to do)
• Amend the text "BaseServlet Global Exception" with some text from the Throwable t - e.g. "java.io.IOException: Connection reset by peer" or whatever the exception message is.

Thank you & Best regards
Blama

[Isomorphic]

Our code (that you highlighted) is passing the underlying exception object to the log system and you're getting a full stack trace from it. Are you unable to configure your log system to do something based on this exception?

If that's the case, what are you suggesting:

1. redundantly log the exception message, even though it's already logged?

2. log this kind of "ordinary" exception in a special category? Not really feasible - different servlet engines throw different classes