After further thought, I am threading the context name into the location where the StatusConfiguration creates the StatusConsoleListener and registering the context name there.
In addition, if the new logger would write to a destination other than standard out or standard error then I do not reconfigure the existing logger in StatusConfiguration.configureExistingStatusConsoleListener(), instead I have the I am now correctly closing the status logger when the context is stopped. I'll push the changes to github after I do a full build On Mon, Apr 19, 2021 at 12:17 PM Tim Perry <tim.v...@gmail.com> wrote: > I rewrote this to shut down listeners based on the contextName. In > testing, I discovered that the StatusConsoleListener is created in > StatusConfiguration, but neither StatusConfiguration nor > StatusConsoleListener receive events to indicate when they should stop. > > It appears that only one StatusConsoleListener object is ever created and > it is never shut down. Looking at the api XmlConfiguration, it calls > StatusConfiguration.initilize() which then either changes the log level to > match the config being parsed or creates a new StatusLogger directed to the > file indicated in the XML configuration. Unless I'm reading the code wrong, > this means that the status logger output location depends on if a previous > app was loaded. If so, then that location will continue to receive > StatusLogger messages but at the log level of the new application's config. > Am I reading this correctly? If I am, is this the intended behaviour? > > > > On Wed, Feb 24, 2021 at 8:29 AM Matt Sicker <boa...@gmail.com> wrote: > >> The StatusLogger has various listeners attached. I think adding and >> removing listeners on startup and shutdown of a LoggerContext might be >> a potential way to do this? >> >> On Wed, 24 Feb 2021 at 01:07, Tim Perry <tim.v...@gmail.com> wrote: >> > >> > Ralph, >> > >> > Thanks for the review. Yep, that *is* a problem...I knew it was a >> singleton >> > but didn't think through the use case you describe. This is ironic >> since a >> > few months ago I recommended that one of my clients bundle log4j in each >> > war rather than on Tomcat's classpath so there would be less chance of >> > instances walking on each other. Sigh. >> > >> > >> > What is the correct behaviour if: >> > >> > - log4j is on Tomcat's classpath >> > - App A has status_A.log >> > - App B has status_B.log >> > >> > Now assume both apps are started. At this point I assume we should be >> > writing to both status_A.log and status_B.log. Now we stop App B. I >> assume >> > we should stop writing to status_B.log but not status_A.log. Further, I >> > assume that if both apps are unloaded from Tomcat, but Tomcat is left >> > running, then the status logger should send its messages to standard >> out. >> > If my assumptions are correct, then maybe we need to keep track of what >> > file, if any, each web app requested messages to be written to. On top >> of >> > that, I think we need a Callback in Log4j's shutdown registry and we >> need >> > to run it last. >> > >> > >> > In some ways this seems like an XY problem. Is the correct question how >> do >> > we reconfigure the logging when a web app shuts down? Or should it be: >> > should the StatusLogger be shared across multiple LoggerContexts? >> > >> > >> > This will be more interesting than I first realized! >> > >> > Tim >> > >> > >> > On Tue, Feb 23, 2021 at 10:38 PM Ralph Goers < >> ralph.go...@dslextreme.com> >> > wrote: >> > >> > > Yeah, I started a review but then I thought it probably would be >> better to >> > > respond here. >> > > >> > > You are on the right track but there is a problem. StatusLogger is a >> > > singleton - there is one instance anchored in a static. You are >> invoking >> > > the shutdown logic from the shutdown of the LoggerContext which is >> not a >> > > singleton. Log4j supports multiple LoggerContexts in an application. >> For >> > > example, if you are old school and running multiple web applications >> in >> > > Tomcat and have Log4j on Tomcat’s class path then you will have >> multiple >> > > LoggerContexts with a single StatusLogger. So if one web app gets >> > > redeployed then its LoggerContext will be shutdown and a new one >> created >> > > all while another app is continuing to run. >> > > >> > > If you’ll notice the StatusConfiguration class in log4j-core tries to >> > > accommodate for this during startup, but it doesn’t do anything at >> > > shutdown. StatusLogger currently isn’t smart enough to handle one app >> > > writing to one destination and a different on writing to a different >> one. >> > > Since StatusLogger is a singleton it can’t really know which app a >> status >> > > log event is for. >> > > >> > > There are a couple of ways I can think of to handle this but none of >> them >> > > is perfect. >> > > Modify StatusConfiguration to keep track of what each >> StatusConfiguration >> > > set up and reset to whatever the prior StatusConfiguration had. The >> problem >> > > with this is that applications might shutdown in a different order >> than >> > > they were started, so figuring out what the prior configuration was >> could >> > > be difficult. >> > > Add the call to prepareToStop() as a new Callback to Log4j’s shutdown >> > > registry. However, this callback would need to run last. The shutdown >> > > registry currently doesn’t support a way to specify the order of >> callbacks. >> > > Support for that would need to be added for this to work. >> > > >> > > Ralph >> > > >> > > > On Feb 23, 2021, at 10:48 PM, Tim Perry <tim.v...@gmail.com> wrote: >> > > > >> > > > Ralph, >> > > > >> > > > I implemented what you suggested. Feel free to suggest improvements. >> > > > https://github.com/apache/logging-log4j2/pull/469 >> > > > >> > > > Tim >> > > > >> > > > On Tue, Feb 23, 2021 at 2:14 PM Ralph Goers < >> ralph.go...@dslextreme.com> >> > > > wrote: >> > > > >> > > >> I would suggest that if it is writing to something other than >> System.out >> > > >> that it be redirected back there and then the OutputStream be >> closed. >> > > >> However, I’ve not looked at the code recently so I am not sure >> what it >> > > >> takes to do that. >> > > >> >> > > >> Ralph >> > > >> >> > > >>> On Feb 23, 2021, at 2:22 PM, Tim Perry <tim.v...@gmail.com> >> wrote: >> > > >>> >> > > >>> Thank you, Volkan. >> > > >>> >> > > >>> I'm not quite ready to submit a PR. I was hoping some of you with >> more >> > > >>> knowledge of log4j-core would weigh in on what we should do about >> > > >> shutting >> > > >>> down the StatusLogger. >> > > >>> >> > > >>> My thought is we choose one of two options: >> > > >>> >> > > >>> Option A: >> > > >>> 1) check if any StatusLogger is writing to standard out or >> standard >> > > >> error. >> > > >>> If not, add one. >> > > >>> 2) stop any loggers that don't write to standard out or standard >> error. >> > > >>> >> > > >>> Option B: >> > > >>> 1) stop any loggers that don't write to standard out or standard >> error. >> > > >>> >> > > >>> Option A could cause the log messages to be split across two >> > > >> destinations, >> > > >>> but they all get sent somewhere. Option B could lose shutdown >> messages >> > > >> when >> > > >>> writing to a file, but by that point it may not matter. >> > > >>> >> > > >>> If any of you have a better idea, I'm happy to implement it. If >> nobody >> > > >>> weighs in on the best option, I'll probably submit Option A as a >> pull >> > > >>> request on Friday or Saturday. >> > > >>> >> > > >>> Tim >> > > >>> >> > > >> >> > > >> >> > > >> >> > > >> > > >> >
