So I’m no expert, but I have been a hobbyist C and Rust dev for a while now, and I’ve installed tons of programs from GitHub and whatnot that required manual compilation or other hoops to jump through, but I am constantly befuddled installing python apps. They seem to always need a very specific (often outdated) version of python, require a bunch of venv nonsense, googling gives tons of outdated info that no longer works, and generally seem incredibly not portable. As someone who doesn’t work in python, it seems more obtuse than any other language’s ecosystem. Why is it like this?

  • nucleative@lemmy.worldEnglish
    303·
    2 months ago

    Python developer here. Venv is good, venv is life. Every single project I create starts with

    python3 -m venv venv

    source venv/bin/activate

    pip3 install {everything I need}

    pip3 freeze > requirements.txt

    Now write code!

    Don’t forget to update your requirements.txt using pip3 freeze again anytime you add a new library with pip.

    If you installed a lot of packages before starting to develop with virtual environments, some libraries will be in your OS python install and won’t be reflected in pip freeze and won’t get into your venv. This is the root of all evil. First of all, don’t do that. Second, you can force libraries to install into your venv despite them also being in your system by installing like so:

    pip3 install --ignore-installed mypackage

    If you don’t change between Linux and windows most libraries will just work between systems, but if you have problems on another system, just recreate the whole venv structure

    rm -rf venv (…make a new venv, activate it) pip3 install -r requirements.txt

    Once you get the hang of this you can make Python behave without a lot of hassle.

    This is a case where a strength can also be a weakness.

    • NostraDavid@programming.dev
      20·
      2 months ago

      pip3 freeze > requirements.txt

      I hate this. Because now I have a list of your dependencies, but also the dependencies of the dependencies, and I now have regular dependencies and dev-dependencies mixed up. If I’m new to Python I would have NO idea which libraries would be the important ones because it’s a jumbled mess.

      I’ve come to love uv (coming from poetry, coming from pip with a requirements/base.txt and requirements/dev.txt - gotta keep regular dependencies and dev-dependencies separate).

      uv sync

      uv run <application>

      That’s it. I don’t even need to install a compatible Python version, as uv takes care of that for me. It’ll automatically create a local .venv/, and it’s blazingly fast.

      • nucleative@lemmy.worldEnglish
        2·
        2 months ago

        I’ve never really spent much time with uv, I’ll give it a try. It seems like it takes a few steps out of the process and some guesswork too.

      • megaman@discuss.tchncs.de
        4·
        2 months ago

        The git repo should ignore the venv folder, so when you clone you then create a new one and activate it with those steps.

        Then when you are installing requirements with pip, the repo you cloned will likely have a requirements.txt file in it, so you ‘pip install -r requirements.txt’

    • oldfart@lemm.ee
      6·
      2 months ago

      OP sounds like a victim of Python 3, finding various Python 2 projects on the internet, a venv isn’t going to help

    • tyler@programming.dev
      6·
      1 month ago

      You have been in lala land for too long. That list of things to do is insane. Venv is possibly one of the worst solutions around, but many Python devs are incapable of seeing how bad it is. Just for comparison, so you can understand, in Ruby literally everything you did is covered by one command bundle. On every system.