I am currently writing a web service using Restlet, and logging with slf4j in front of log4j. Currently I have standard log4j Appenders in place for logging to files. What I was trying to do is also include log output in the HTTP Response, using a custom Appender.
The issue I am seeing is that Appenders by default have no ability to access the context of the request being made, which makes sense since theoretically the request could finish before an asynchronous Appender gets around to executing. I am still curious as to whether this is possible, perhaps by making the Appender synchronous and passing a Response object with the log call. I can't find a way that log4j would support this, would another framework like logback? I wouldn't necessarily use this method in the end because of the performance implications, but still I am curious.
FYI my current workaround is a custom log method which adds the entry to the Response, then calls the slf4j method for standard logging. Downside to this is having to use a custom method, and I only get log entries for code I control (libraries I'm using that just use Appenders don't get logged to Response)