On 1/31/2018 5:00 PM, Alexander McLin wrote:
During the tool's start up period prior to calling the main function I set up a log receiver to receive messages at the desired level and place it inside a sync loop within its own thread. Each time a sync event is received, it is written out to the port, then loop back to waiting for the next sync event.

It works reasonably well except I have a new problem, when the tool exits, it often exits before the thread handling the log receiver propagation to the port has finished receiving all the log events, as a result my logging output is frequently truncated.

Given this undesired situation, I need to figure out a better way to reliably propagate all log messages to ports before the tool exits normally or due to a raised exception.

There may be a better way, but I handle this kind of thing with dynamic-wind.  The program's main function looks like

        (lambda ()
            ;;; startup services
            ... )

        (lambda ()
            ;;; program's purpose
            ... )

        (lambda ()
            ;;;shutdown services
             ...  )

There is `with-logging-to-port` except I will need to set up multiple ports and the idea of wrapping the tool's main body with multiple `with-logging-to-port` for each port isn't appealing and it still doesn't resolve the problem.

I use  with-logging-to-port  in the individual logger threads to direct their output.  I don't wrap it around all the code.

I was wondering if anyone has a better suggestion? Is there a way to detect if there are pending log events waiting to be received by the log receiver?

Not that I know of, but if you structure the logger so that it must be specifically shut down, you can drain the message queue before terminating.


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