Being able to install packages

[facundobatista]

We've been talking a lot with @sils1297 about the best way for a project developer to tell their users to install a package without having to care about virtualenvs, and we found the best way would be to have an option like:

    sudo fades --install=mypackage

In this case, fades would:

• create a virtualenv, as usual (even reuse one if already has it!)
  • note1: user could do --install=mypackage==1.3
  • note2: or even do --install=mypackage=1.3 -d dep1 -d dep2 (but we really expect that 'mypackage' would have dependencies already defined at setup.py, directly usable by pip)
• find out the scripts or entry-points defined in mypackage (possibly exploring mypackage's setup.py manually); these scripts/entrypoints were handled properly by setuptools in the virtualenv (it just copies the scripts, or create specific .py for the entry points)
• copy those scripts to the same system path from where 'fades' is being executed (which AFAIK it would be the better way to know, in a sane multiplatformly way) which is the default system path)

Let's see for example what would happen with a sample project, 'coala':

• you'll do: sudo fades --install=coala
• it will create a virtualenv, install coala there, and you'll see how setuptools created scripts for coala's entry points:

    $ ls -l ~/.local/share/fades/d9127346-8e11-4731-a9ef-fd9763c5b851/bin/
    total 56
    ...
    -rwxrwxr-x 1 facundo facundo  278 jul 21 11:44 coala
    -rwxrwxr-x 1 facundo facundo  281 jul 21 11:44 coala-ci
    -rwxrwxr-x 1 facundo facundo  283 jul 21 11:44 coala-dbus
    -rwxrwxr-x 1 facundo facundo  290 jul 21 11:44 coala-delete-orig
    -rwxrwxr-x 1 facundo facundo  285 jul 21 11:44 coala-format
    -rwxrwxr-x 1 facundo facundo  283 jul 21 11:44 coala-json
    ...

• fades would copy those scripts to /usr/bin because...

    $ which fades
    /usr/bin/fades

[sils]

From a usability POV I'd rather prefer if you'd use subcommands: fades install coala, without --. On the long run it'll bite you if you don't. (It's biting us :P)

[facundobatista]

Do we need this functionality in fades, existing pipsi?