installing apt dependencies in plugin for docker

[wolflu05]

Hello,

I want to develop a CUPS label printing plugin for my printer. I already found a python library pycups [GitHub] which works well for printing in my first tests.

The only issue I have is, that the following apt packages need to be installed inorder that the wheel building of the pycups packae can succeed. gcc, libcups2-dev, python3-dev

For a bare metal install I can document running sudo apt install gcc libcups2-dev python3-dev, but for docker this won't work or would require an execution after each recreate. Does anybody has a good idea how to solve this issue without maintaining an own inventree image which has these dependencies?

[matmair]

@wolflu05 I would leave that to the user. I have a mixin that runs user-level installs but that is not production ready.
There are several ways to achieve an install in docker - I probably would use a custom entrypoint.

[wolflu05]

@matmair Im not really sure what the answer to this problem is? Do you want me to create an issue for this contrib docker image tag?

[matmair]

@wolflu05 if you feel that is the right solution yes. I think sdist is an easier (and better scaleable) solution but that probably needs to be decided on a per-case basis.

[matmair]

I mainly want to clean out issues/get problems into FRs or bug reports before 0.9.0

[wolflu05]

@wolflu05 if you feel that is the right solution yes. I think sdist is an easier (and better scaleable) solution but that probably needs to be decided on a per-case basis.

@matmair What would you think in this case for my cups plug-in?

[matmair]

@wolflu05 I think cups should work well with sdist

[SchrodingersGat]

There are a few options I can imagine:

Custom Entrypoint

As @matmair says above you could have a custom entrypoint command which installs libcups2-dev every time you launch the container. Not super efficient.

Custom Image

You could have an image which inherits from the inventree/inventree image and add a command to install cups when you build the image.

External Container

You could have another docker container which has cups support and write some code to send label data to that. Not ideal, you'd have to write two pieces of code and it would be a tricky thing to get right.

Install cups in the InvenTree image

Having cups support might be a good thing in general for InvenTree for label printing?

[matmair]

The image is already big, I would caution against a route of adding more stuff to it. Maybe creating another stage to the build that creates a -contrib image would be a good middle-ground?

[wolflu05]

That sounds nice, but doesn't generally solves this problem.

[matmair]

What problem is it not solving? It would enable you and anbody else who needs dependencies to get them in an image.
It should just not be the standard image as it would probably get pretty big.

[wolflu05]

oh ok, so this image would contain some more libs as they getting requested. I had a wrong view of it.