Make Skyfield, Astronomy optional

[jrd]

astronomy module might interest some people I’m sure, but the skyfield dependency will pull numpy which is huge (and maybe complex to build on some environment).

So is it possible to have a workalendar package with a [astronomy] extra that will pull skyfield and skyfield-data?
That way, people who also needs the astronomy module will request workalendar[astronomy] and others just workalendar.

This is, of course, if it’s possible.
What do you think?

[ewjoachim]

One other possible solution could be to have a different package (in the same codebase) that uses those libs to generate the astronomical information and that we can run once a year or once a release with everything, and have workalendar use these information but not require the libs themselves.

That would take advantage of the fact it's very predictible for long term. We could generate 50y worth of astromonical data and it's likely not to change a lot in the next 50 years.

[jrd]

Yes that seems to be a good idea.

[ewjoachim]

(Would that be compatible with our dependencies' licences ? I think so but I don't know)

[jrd]

How can I help getting this done?

[ewjoachim]

I would have like to get an opinion from @brunobord before spending time on this. He's the maintainer and he's the architect for this lib :)

If he says 👍 then I believe you can start working on a PR.
What needs to be done is to create an intermediary format, easily writtable on disk (I'd say JSON) that lets you calculate all the working/non-working days that depends on astronomy elements without actually calling the astronomy-related libs (so maybe this will be for example a list of all relevant calculation results for the 50 next years). This probably means the first thing to do is audit the entire lib and find how the astronomy-related libs are called.

Then once this is done, we need a script that will generate those JSON files, and we'll need a bit of "packaging magic" so that it's easy to run the script with the astronomy libs, and we can safely remove them from the runtime workalendar (extras_require could be a lead, but I'd prefer if we could remove those entirely from the lib. That being said, may a simple file requirements.astronomy.txt would suffice).

Does this make sense ?

[jrd]

Yes totally. I wait for @brunobord opinion. Thanks for the quick answer.

[brunobord]

Made a 16.0.0rc1 release ; will have to make a few tests tomorrow, we're getting closer.

[brunobord]

The latest release (16.0.0) includes your tremendous work. Thank you a million for your time and your patience. You rock!

• https://pypi.org/project/workalendar/16.0.0/
• https://github.com/workalendar/workalendar/releases/tag/16.0.0

Happy upgrading!