cli: notify users of runner usage

[ltalirz]

The extra query performed in verdi process list to get the load on the
daemon runners is slow - and usually results in no output for the user.
This PR at least lets the user know what is being queried (which also may be useful
to monitor runner load).

[ltalirz]

Not sure why the tests failed... didn't change docs + this should not be backend-specific behavior

[sphuber]

Thanks @ltalirz . Fine by me, would just not add the case where daemon is not running as that is already covered in verdi process list itself.

[ltalirz]

Thanks @ltalirz . Fine by me, would just not add the case where daemon is not running as that is already covered in verdi process list itself.

Thanks - I've pulled out that check from the previous function and now call the worker query only when needed.

[ltalirz]

Note: I first removed these changes again but then noticed that they also appear on the CI pre-commit check - some updated version perhaps?

[ltalirz]

@sphuber Now that the print is gone when no daemon is running (which I think is the right thing to do here), the test checking its output fails.

What do you think is the best approach here - fake a running daemon or move this test to the daemon tests?
I'm wondering whether one could fake a running daemon by running things inside a with block that creates the pid file, something along the lines of (untested)

with open(get_daemon_client().circus_port_file, 'w', encoding='utf8') as fhandle:
   fhandle.write(123)

   test..

Perhaps there are cleaner approaches

[sphuber]

Perhaps there are cleaner approaches

The typical way is to simply monkeypatch the DaemonClient.is_daemon_running property to always return True. This is made easy using pytest, so I have migrated the test to pytest and it should now work. Let me know if you also are happy with the changes, then I will approve and merge @ltalirz

[codecov]

Codecov Report

Merging #4663 (c0d1f23) into develop (fa498bc) will decrease coverage by 0.01%.
The diff coverage is 80.00%.

@@             Coverage Diff             @@
##           develop    #4663      +/-   ##
===========================================
- Coverage    80.47%   80.47%   -0.00%     
===========================================
  Files          530      531       +1     
  Lines        36944    36950       +6     
===========================================
+ Hits         29727    29731       +4     
- Misses        7217     7219       +2     

Flag	Coverage Δ
django	74.98% <80.00%> (-<0.01%)	⬇️
sqlalchemy	73.89% <80.00%> (-<0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
aiida/cmdline/utils/common.py	67.04% <40.00%> (-0.61%)	⬇️
aiida/cmdline/commands/cmd_process.py	47.85% <88.89%> (+0.25%)	⬆️
aiida/engine/__init__.py	100.00% <100.00%> (ø)
aiida/engine/daemon/__init__.py	100.00% <100.00%> (ø)
aiida/engine/daemon/client.py	75.26% <100.00%> (+0.13%)	⬆️

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[ltalirz]

thanks @sphuber !