Usage with different python versions about pickley

[zsimic]

pickley currently defaults to system python, but can install/package with any python.

Which python to use can be specified via command line: pickley --python 3.6 install ... (or -P for short). Value for --python can be:

• full path to a python installation, like for example /usr/bin/python
• command name like python2.7 or python3
• short form like py3.6 of 3.6 or even just 36
• you can also be more specific like 3.7.3

A config file can also be provided in <base>/.pickley/config.json (example if you dropped pickley in ~/.local/bin: ~/.local/bin/.pickley/config.json).

Example config:

{
  "python_installs": "~/.local/pyenv/versions",
  "python": {
    "3.7": "awscli"
  },
}

The above example would tell pickley to look at ~/.local/pyenv/versions for python installations (in addition to what you already have on $PATH).
Then default to 3.7 for awscli (if no --python specified).

I plan to provide better support for this:

• respect module's python_requires (if there's any), don't default to system python for everything
• document how python versions are found :)
• see what's the best way out there people are getting their "clean python" installations, and see if it could be made to work with as little configuration as possible :)

Few examples (without config):

pickley -P3.7 install tox
pickley -P `which python3` install tox
pickley -P ~/.local/pyenv/versions/3.7.3 install tox

[naphta]

@zsimic Great answer thank you.

In that example configuration above for pointing the default installation to pyenv would that be a good idea for doing by default? Just do a quick check for pyenv if it's installed; if so default to it?

If that is a simple enough thing to do I don't mind opening up a feature branch / pull request to add that feature.

[zsimic]

Yes, that would make sense to do I think, as pyenv is pretty popular.
Didn't do it yet as I tried to keep it simple and reach 100% test coverage first.

Next things I plan to do are (in this order):

• fix edge case around dashes vs underscores in package names (currently broken: you can't install foo-bar, have to manually state it as foo_bar...)
• provide an upgrade command (accepting 0 or more args)
• write a good documentation
• respect python_requires if package specifies one (so not to have to configure anymore)
• fancier python search (so stuff like auto-detect pyenv)

Contributions absolutely welcome! :)