I'm sympathetic to the anxiety for getting everything designed right, but at some point it's better to stop pondering possibilities and just get something working ;).
I have some experience in this kind of design space but 0 knowledge about log4j internals, and my totally unrequested suggestion is that, since probably simplicity / speed / garbage-free operation are valued, I'd go for N ring buffers of N entries each, with N defined and everything allocated at start-up time. Every new trigger swaps in a new ring buffer to be used while the previous ring/s get drained. For the extreme case of multiple triggers coming in a burst, you'd be swapping rings at every entry. Rings are emptied until the triggering entry, it's the simplest (or only?) way to have a well-defined result. For my immediate needs I guess I'll have to make do with some external post-processing... Thank you! Best, --- Horacio > On 25 Nov 2019, at 2:47 pm, Ralph Goers <ralph.go...@dslextreme.com> wrote: > > See https://issues.apache.org/jira/browse/LOG4J2-1137 > <https://issues.apache.org/jira/browse/LOG4J2-1137>. It has been on my todo > list for quite a while. What I plan on implementing is a “TriggeringAppender” > where you can attach a custom trigger or triggers to cause the event to fire. > The problem I haven’t figure out is in capturing and emitting the events. It > should use a ring buffer but when the event fires you don’t want to cause a > pause while all the events are logged so you would probably need more than > one RingBuffer. And what if the trigger fires again before the first trigger > has logged all the events? I want to figure out this behavior before I start > writing it and I just haven’t had the time to design it. > > Ralph > >> On Nov 24, 2019, at 8:52 PM, hmijail+lo...@gmail.com wrote: >> >> Hi all, >> >> I am looking for a way to do a lookahead regex filter: ignore log lines, >> unless there is a match with a given pattern, in which case the N previous >> lines should be stored. >> >> The RegexFilter filter doesn't seem to support this, or at least I haven't >> managed to make it work. (I would have been surprised to find it worked >> anyway) >> >> Any tip on how to do this kind of thing? >> >> Best, >> --- Horacio >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: log4j-user-unsubscr...@logging.apache.org >> For additional commands, e-mail: log4j-user-h...@logging.apache.org >> >> >
