undefined | Better HN

0 pointsqbasic_forever3y ago0 comments

You have to remember to activate them. Node/npm has a similar concept with its scripts execution, but it automatically runs them in the local node_modules environment (i.e. virtualenv).

You might think this is silly but think about something like making a systemd service to run your python script in a venv--how do you do it? You have to activate the script or call its python bin, but it's not obvious how to do that in any python docs.

0 comments

3 comments · 1 top-level

wswope3y ago· 2 in thread

It is silly. You put together a three-line bash script to activate the venv, run a pip install, and call your program.

The Python docs do cover this topic, and do so rather well: https://packaging.python.org/en/latest/guides/installing-usi...

jakewins3y ago

But the problem isn't my python environment - the problem is distributing packages, particularly libraries, to downstream users. That one over there uses virtualenvs and a bash script she wrote, that one just ran "pip" and has 4 different system python installs entangled into each other; that one ran `pipenv install`, that one `poetry add`.

How do I ensure that at each customer site, my library has the set of dependencies it needs, with versions that it is known to work with? Each installation method has a different constraint solver, a different means of specifying dependencies.

wswope3y ago

Did you mean to respond here? This is a nonsequitor from the GP I was responding to. Regardless:

If your question is "how can I ensure technical end-users have the same set of python packages as I do for the code they run using standard pip+venv?", the answer is to pin dependencies in a requirements.txt file.

If your question is "how do I stop end users from installing dependencies for my software cowboy-style?", the answer is to write installation and usage instructions, and/or include an AIO run script.

If your question is "how do I package my library so that end users' package managers know my library's downstream dependencies when they install it?", you build a wheel using `pip wheel`, which again relies on a requirements.txt. If I'm understanding you right, you're mistaken that you have to handle the package managers separately; they all use pip + wheels under the hood. Conda is a bit of an asterisk in that you can package things differently if you desire, but it plays nice with pip + wheel builds too.

https://docs.conda.io/projects/conda-build/en/latest/user-gu...

j / k navigate · click thread line to collapse