RFC to rewrite language family

[sophiewigmore]

Readable

Signed-off-by: Timothy Hitchener thitchener@pivotal.io
Signed-off-by: Sophie Wigmore swigmore@vmware.com

[kvedurmu]

@thitch97 @sophiewigmore thanks for putting this together, this looks awesome! Couple comments/thoughts:

• Procfile ID in the order groupings should be paketo-buildpacks/procfile instead of paketo-community/procfile

without the need for the requirements.txt workaround we currently do ...

• This reads a little confusing (I initially thought this meant that users cannot use a requirements.txt)

Basic Python start command

• Could we add an example here? e.g docker run -it python-image "run.py"
• I'm assuming that this would error out without user provided args. Is that correct?

[arjun024]

Is there no way to install/provide pipenv without requiring pip?
Is this because pipenv requires additional modules not provided by cpython?

I notice later in the doc you mention "We can reuse existing ecosystem tooling like pip to aid in the installation of packages using pipenv". But I think if it's possible, It would be cleaner for a pipenv workflow to exist that is independent of pip.

[ryanmoran]

I think this should be possible, but would require that we have different dependencies than what is present in the existing buildpacks. The existing buildpacks have source code for pip and pipenv as dependencies. This means we need to use python or pip to install each. I believe there is a binary distribution concept called a wheel that we could use.

[arjun024]

I didn't know about wheels. Pipenv does publish wheels (https://pypi.org/project/pipenv/#files) but it looks like the conventional way to even install a wheel is through pip, though it looks like a zip you can unpack to disk. Regardless, it would be pretty cool if the buildpack doesn't have to bother about building binary from a source distribution.

[joshzarrabi]

According to the docs you can run curl https://raw.githubusercontent.com/pypa/pipenv/master/get-pipenv.py | python

Looks like that installs pip anyway

curl https://raw.githubusercontent.com/pypa/pipenv/master/get-pipenv.py | python3
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1558k  100 1558k    0     0  4068k      0 --:--:-- --:--:-- --:--:-- 4057k
Collecting pip
  Using cached https://files.pythonhosted.org/packages/cb/28/91f26bd088ce8e22169032100d4260614fc3da435025ff389ef1d396a433/pip-20.2.4-py2.py3-none-any.whl

[arjun024]

I took a look at pipenv's whl and it seems to to be a source code distribution and not binary.
A useful stackoverflow conversation about whl

[joshzarrabi]

I broke open the source and wheel distributions and they are both just tarballs of python source code. I think it may be possible to install pipenv without pip but that seems hard and unnecessary.

[ForestEckhardt]

I was looking around pipenv issues and found this, thought it might be interesting/helpful.

[joshzarrabi]

Looks good to me!