Re: Logging librarie (Re: Debugging COMM:START-UP-SERVER hang)

Link to slog?

Marco Antoniotti, Professor, Director         tel. +39 - 02 64 48 79 01
DISCo, University of Milan-Bicocca U14 2043   http://dcb.disco.unimib.it
Viale Sarca 336
I-20126 Milan (MI) ITALY

REGAINS: https://regains.disco.unimib.it/

On Sun, Mar 1, 2026, 14:55 Tim Bradshaw <[email protected]> wrote:

> On 28 Feb 2026, at 21:22, Alexey Veretennikov (as alexey dot veretennikov
> at protonmail dot com) <[email protected]> wrote:
> >
> > Personally I don't like too much dependencies, so I just run a logging
> thread/process with a mailbox where I send anything I want to log (or
> eventual shutdown message), take out a message in a loop and print it.
> Seems easier than to learn yet another library.
>
> I have the advantage of having written slog (so I'm blowing my own trumpet
> here), but this is exactly one of the ways I've used it:
>
> (defmethod slog-to ((destination mailbox)
>                     (entry log-entry)
>                     &key)
>   ;; a mailbox is now a log destination
>   (mailbox-send destination entry)
>   entry)
>
> (define-condition terminating-log-entry (log-entry)
>   ;; Just a marker
>   ())
>
> (defun mailbox-log-reader (mailbox &optional (stream *debug-io*))
>   ;; Read log entries and print them till we get a terminating entry
>   (do ((entry (mailbox-read mailbox) (mailbox-read mailbox)))
>       ((typep entry 'terminating-log-entry))
>     (slog-to stream entry)))
>
> (defvar *log-mailbox* (make-mailbox))
>
> (defun ts (n (mailbox *log-mailbox*))
>   (process-run-function
>    "foo" ()
>    (lambda ()
>      ...
>      (logging ((t mailbox))
>        ...
>        (slog "World exploded again")
>        ...
>        (slog 'terminating-log-entry)))))
>
> Slog's trick is that log entries are conditions and logging is signalling
> them.  LOGGING then establishes condition handlers (which always decline to
> handle the condition so control flow just continues) which deal with log
> entries.
>
> It may be that other logging frameworks do the same thing, but they all
> looked too complicated to understand.  The S in slog is for *simple*: I
> wanted to be able to log events not to deal with some awful bureaucracy
> which has seeped out from the Java mines.
>
> --tim