ELI5 Using python virtual environment in docker container.
ELI5 Using python virtual environment in docker container.
I read some articles about using a virtual environment in Docker. Their argument are that the purpose of virtualization in Docker is to introduce isolation and limit conflicts with system packages etc.
However, aren't Docker and Python-based images (e.g., python:*) already doing the same thing?
Can someone eli5 this whole thing?
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It's not necessary but there is no reason not to.
Pros:
- production and development programs are more similar
- upgrading your base image won't affect your python packages
- you can use multi stage builds to create drastically smaller final images
Cons:
- you have to type
venv/bin/python3instead of justpython3in the run line of your dockerfile
Hah my base python has never seen a command.
Biggest reason for me is that local dev happens in a venv and translating to a container is 100% 1:1 then
It’s easy to set the path to include the venv in the Dockerfile, that way you never have to activate, either in the run line, nor if you exec into it. Also this makes all your custom entry points super easy to use. Bonus, it’s super easy to use uv to get super fast image builds like that. See this example https://gist.github.com/dwt/6c38a3462487c0a6f71d93a4127d6c73
upgrading your base image won’t affect your python packages
Surely if upgrading python will affect your global python packages it will also affect your venv python packages?
you can use multi stage builds to create drastically smaller final images
This can also be done without using venv's, you just need to copy them to the location where global packages are installed.
Upgrading the base image does not imply updating your python, and even updating your python does not imply updating your python packages (except for the standard libraries, of course).
Sure, but in the case where you upgrade python and it affects python packages it would affect global packages and a venv in the same way.
Sure If that happens. But it may also not. Which is actually usually the case. Sure, it's not 100% safe, but it is safer.
If you're on an apple silicon mac, docker performance can be atrocious if you are emulating. It can also be inconvenient to work with Docker volumes and networks. Python already has
pyenvand tools likepoetryandrye. Unless there's a need for Docker, I personally would generally avoid it (tho I do almost all my deployments via docker containers)