Add CONTRIBUTING.md

[jtpio]

Fixes #134.

This is the set of commands I've used so far and they have been enough for regular development.

@choldgraf @SylvainCorlay @maartenbreddels feel free to jump in and add anything missing.
I'll do a second pass on it a bit later today / this week.

[choldgraf]

I'll take another pass at getting this set up for myself this week. I still haven't been able to get Voila working in dev mode :-/

[jtpio]

Second pass done. This should be ready to go.

@choldgraf did you give it another try?

[choldgraf]

will give this a shot today

[choldgraf]

Some notes:

• Install instructions worked this time w/ pip install -e . dunno if that was a change on my end or your end but 👍
• I got an error about not having the right version of pygments installed when I tried to run voila. running pip install -U Pygments got it to work. Perhaps that should be added in here?

[jtpio]

* I got an error about not having the right version of pygments installed when I tried to run `voila`. running `pip install -U Pygments` got it to work. Perhaps that should be added in here?

It should normally be installed automatically (via jupyterlab_pygments)

[choldgraf]

Yeah - I think I just hadn't updated it recently which is why I had an outdated version. Maybe just add a "conda update XXX" for the required conda packages? Though I agree most developer types could have figured it out

[choldgraf]

Ah one more point here after experimenting a bit more. It doesn't seem like this installs the voila server extension (at least, I'm getting a 500 error when I run jupyter lab and hit /voila. Is that right?

[SylvainCorlay]

I got an error about not having the right version of pygments installed when I tried to run voila. running pip install -U Pygments got it to work. Perhaps that should be added in here?

Both the conda recipe and setup.py for jupyterlab_pygments require pygments>=2.4.1 so it is weird that you could get it with an older version. I don't think we should specify anything though.

[SylvainCorlay]

Ah one more point here after experimenting a bit more. It doesn't seem like this installs the voila server extension (at least, I'm getting a 500 error when I run jupyter lab and hit /voila. Is that right?

Indeed, development installations don't install data files. Jupyter server extensions rely on a configuration directory system in share, where the assets for the voila jupyterlab extension are placed.

In the case of a development installation, the extension can be installed and enabled with:

• for the classic notebook server

jupyter serverextension install --py --sys-prefix --symlink voila
jupyter serverextension enable --py --sys-prefix voila

the --symlink is not supported on windows.

• for jupyter_server

jupyter extension install --py --sys-prefix --symlink voila
jupyter extension enable --py --sys-prefix voila

[maartenbreddels]

I think we can fix all that by adding a custom devel command in setup.py, and symlinks on windows 10 seem to work fine, but requires admin mode (I think). Maybe a 'good first issue' to open?

[SylvainCorlay]

I think we can fix all that by adding a custom devel command in setup.py, and symlinks on windows 10 seem to work fine, but requires admin mode (I think). Maybe a 'good first issue' to open?

Yes, that would make sense.

In the mean time, we could add these instructions for those who want to use the server extensions in development mode.

[jtpio]

jupyter serverextension install --py --sys-prefix --symlink voila

Isn't the jupyter serverextension enable command enough? (no install subcommand for server extensions)

We can also add instructions for the notebook extension (which adds the "Voila" button to the classic notebook).
And when #40 is merged instructions for the JupyterLab extension.

[yuvipanda]

If you're using this with jupyter_server (instead of notebook), you'll need to run jupyter extension enable instead of jupyter serverextension enable

[jtpio]

Updated based on #182 and @yuvipanda's comment.

[SylvainCorlay]

remove --user.

[SylvainCorlay]

It seems to me that --py is always required?

[jtpio]

--py throws the following for me:

KeyError: 'The Python module voila does not include any valid server extensions'

[jtpio]

Full command: jupyter serverextension enable voila --sys-prefix --py

[SylvainCorlay]

indeed we don't have an entry point for a jupyter server extension in __init__.py. We should probably just remove the --py.

[choldgraf]

Woot, thanks for this @jtpio