Re: having trouble modifying guix-daemon

["Ludovic Courtès" <ludo@gnu.org>]

Hello,

Robert Vollmert <rob@vllmrt.net> skribis:

> Instead, I’d like to improve on my experience, which I’m sure others would run
> into:
>
> - working with guix, doing some calls to guix pull, guix system reconfigure.
> - notice that it takes quite a while, and often hangs for extended periods of
> time without clear indication what it’s doing, whether it’s even doing anything
> - look through the manuals to find out how to get more useful output to answer
> those questions, learn about “debug” and “verbose” command line options.
> - through trial and error, learn that “verbose” doesn’t seem to be helpful, but
> “debug” does add some output
> - but that output is mostly just pages and pages of identical locking/unlocking
> the store lines
>
> In my opinion, the debug output, if available, should help to answer the original
> questions. And certainly not prompt more questions, such as “is this just spinning
> on a lock?” which have an easy answer.

OK, I see.

Fundamentally, we should treat “guix takes a while without printing
anything” as a bug.  I think the UI should always show a progress bar,
or a spinner, or at the very least a message indicating that some
time-consuming action is taking place.

For example, I know that an initial ‘guix pull’ takes a long time
without printing anything: that’s because it’s cloning the repo, and we
don’t have Guile-Git hooks to report on the progress of that operation.
That’s clearly something to fix in the UI.  Is this specifically the
slowness you were looking at?

‘guix system’ tends to take a bit too long to just compute the system
derivation; we should probably optimize the whole thing, but also
consider adding some sort of progress report.

These are two examples of slowness where getting debugging output from
the daemon does not help at all understand what’s going on.

> To that extent, I’d like to improve the output of debug level guix pull logging.

So, I think what I’m saying is that I’d rather improve progress
reporting in the UI, than add debugging statement.  Logging and progress
report are actually almost the same thing, except that progress report
is meant for normal human beings.  :-)

Ludo’.