[PATCH 3 of 3] docs/installation: clarify root privileges requirement for 'pip install'

[Mads Kiilerich]

On 03/15/2015 01:04 PM, Andrew Shadura wrote:
> Hello,
>
> On Sat, 14 Mar 2015 23:03:27 +0100
> Mads Kiilerich <mads at kiilerich.com> wrote:
>
>>> +Note that this method requires root privileges. When installing as
>>> a regular +user, you can use::
>>> +
>>> +    pip install --user kallithea
>>> +
>>> +or (recommended) install Kallithea in a virtualenv (next section).
>> I think we should give a different advice.
>>
>> In my opinion, pip should only be used inside a virtualenv. Running
>> it as root is wrong.
>>
>> I don't know this --user option. How does it work ... if it does work?
> It really does work, it installs packages into ~/.local, which is
> useful if you just want to test things out, and if you do want to mix
> your system packages with locally installed ones.

How does it work? Will the global installation of pip hook into Python 
startup and inject packages from .local in sys.path? How about 
executable scripts - where are they placed?

Either way, I understand that pip --user still will install the packages 
in a shared location. That will make it very hard to uninstall or "start 
over". I guess it also makes it impossible for the a user to have more 
than one Kallithea instance.

I think we need more clarification of pros and cons of the different 
options before we start recommending more options.

In my opinion, virtualenv is the only _real_ option. It makes pip simple 
and managable so we know exactly where the dependencies for this app is 
installed. Running pip without virtualenv (with or without --user) can 
easily create situations that are very hard to recover from.

/Mads