split watchmedo logic into _watchmedo.py (yaml and argh independent)

[replabrobin]

To avoid using the yaml & argh dependencies for simple programmatic use I split out the logical parts of watchmedo.py into a separate module _watchedo.py; watchmedo can then import the functions it needs and the command stubs can use them .

[BoboTiG]

I am not sure to understand the need and the patch 🤔
Could you elaborate please?

[replabrobin]

I have a cgi web application for which there is a need for a test harness that can be used in development. Mostly I can use a simple bash script to run a wsgi app and use inotify to check for underlying changes. My Boss uses a mac and inotify won't work. Conceptually watchmedo can do the restarts, but I wanted to make a simpler solution using just python. I can do all that I need with watchdog, but to use the auto_restart function itself I have to copy the code from watchmedo.py or incur the extra requirement of pyyaml and argh. By separating out the logic part of the code in watchmedo I can use the auto_restart logic without having to import argh & yaml (so they're no longer required at run time). It's really a minimalist desire.

An additional issue is that the watchmedo auto_restart becomes part of the parser and I would need to interface via an argv. I have simple python objects and that would mean conversion to argv form which is not required. Creating a post parse args object from python is easier.

I can live without this patch, but I dislike just copying the code across.

[BoboTiG]

Oh I get it now... Sorry for the late answer :)

You are importing stuff from _watchmedo in your own code, right? That seems good to me, those changes cannot hurt (:crossed_fingers:).

[ktdreyer]

See also #824 , argh is umaintained upstream and I think we should remove it.

[BoboTiG]

Now that argh was removed (cf. #836), #847 could be useful for you, @replabrobin ? It avoids rewritting too much part of the module.

[BoboTiG]

Superseded by #847.