[Python-ideas] install pip packages from Python prompt

[Steve Barnes]

On 01/11/2017 06:54, Wes Turner wrote:
> Suggestions to help to minimize unnecessary logged bandwidth use and 
> even work with a closed loop LAN:
> 
> This reads from the filesystem:
> 
>      import requests
> 
> This would read from the PyPi service over the network bandwidth:
> 
>     #!pip install -U requests
>     #%run pip install -U requests
> 
>     #pip('install -U requests')
> 
> This doesn't work because you SHOULD restart the interpreter after 
> running pip (because imports are cached):
> 
>      import requests
>      !pip install -U requests
>      import requests
> 
> Some tips on running educational environments for beginners (optionally 
> in a lab):
> 
<Snipped a lot of good stuff>

One tip that I have used when teaching python in a closed, (sometimes 
internet free environment), was to pre-prepare by, in an on-line 
environment:

  1. Create a virtual environment with the version of Python that I am 
going to be teaching on the target platform
  2. Activate that environment
  3. Ensure that I am On-line
  4. Download the pip install packages that I know I will need by using 
`pip download` to download but not install the packages, ideally using 
the -r requirements.txt syntax, (plus any windows specific builds from 
Christoph Gohlke's site).
  5. Go Off-line and run pip install with the downloaded package - if I 
hit any errors due to packages having unspecified dependencies add those 
to the requirements list and repeat from 3. (While I am at it I often 
log an issue with the package maintainer).
  6. A fast, personal, run through my lesson plan to ensure that I 
haven't missed anything.

I normally also download a few goodies that might not be essential to 
the lesson but that can act as a teaser for the more interested students.

At the start of the first lesson I give the students the downloaded 
packages directory, usually on a USB key, and get them to pip install 
them while explaining the difference between local and on-line installation.

I know that I could save having to get the students to run pip by 
packaging up the virtual environment as a portable, or using by 
pyInstaller, but having them run pip on the local downloads gives me a 
chance to explain how to do it in the wild.

BTW while Docker is great for this it is a whole other learning 
experience, (plus getting it running with some corporate security & 
anti-virus can be quite a challenge).

These USB keys are often re-used by other co-workers as a getting 
started or after my computer got changed/re-imaged starting point.

-- 
Steve (Gadget) Barnes
Any opinions in this message are my personal opinions and do not reflect 
those of my employer.

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