Auto-install python-jl Jupyter kernel?

[marius311]

Would you accept a PR that makes it so that upon installing PyJulia, a python-jl-based Jupyter kernel is installed (if Jupyter is present)? I can write this.

[tkf]

I'm against for auto-install because

• Even ipykernel does not install the kernel https://ipython.readthedocs.io/en/stable/install/index.html
• It is very common to have multiple Python virtual environments. I think it would be impossible to sanely handle situation where you install one kernel in environment A and then after in environment B.
• I want to get rid of python-jl at some point (not very soon, though). I think Generate system image with PyCall in "PyJulia-mode" #256 and Use python binary instead of libpython when it's a PIE PyCall.jl#612 are the better way.

Having said that, I think it is a good idea to have something equivalent to python -m ipykernel install (say python -m julia.ipykernel install --python-jl). We can also solve #223 with this.

[marius311]

I'm still interested in the kernel installer, that's fine that its not auto-installed. Should I work on that (I think it's not much work) or do you think it's not worth it given how close you may be on getting rid of python-jl entirely?

[tkf]

I think it's still better to have python -m julia.ipykernel install command due to #223. Adding --python-jl flag for this command to choose python-jl as a "backend" sounds good to me (unlike python-jl -m IPython, there is no obvious command to do this ATM).

[marius311]

I think it's still better to have python -m julia.ipykernel install

Sounds good, that's what I'll aim for.