🔒 best practice: supporting user-contributed code

[mystic sundial]

I'm developing a generic computer vision application in Python. I use dxcam to grab a user's screen, use yolov8 in ultralytics to detect features, and then use opencv to decorate the features detected in the screenshot. I then display a click-through always-on-top opencv window, so it appears to the user in near-real-time. Think something like Snapchat filters.

I am implementing the decoration code as classes that have a consistent interface. For example, one might draw boxes around flowers, one might put a tiara on any heads, one might draw a black box over guns. The user will be presented with a GUI that shows all the available decorators, and then selects which to "turn on".

I want to make it as easy as possible for other people to contribute other decorators. What I am imagining so far is to have a package folder /decorators/. To create a new decorator, a user will simply drop a .py file into that folder - for example, corvusdec003.py. That py file MUST define a class named decorator, which must have functions description (shown to user in GUI), initialize, and decorate_image.

Is this the best solution? I would still need some way to programmatically enumerate all the modules in the package and load the decorator class from each of them. I'm sure there's a way to do that, but this seems strange enough that I want to ask if there's a better way (to do something that admittedly is a weird thing to do, automatically incorporating user-contributed code).

[languid vigil]

@mystic sundial

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[tacit laurel]

If you're targetting iphone, I think that's against appstore policy

[mystic sundial]

I am not. Windows desktop. Not even pip, just distributing on GitHub.

[tacit laurel]

ah, ok then

If you're asking about plugins, having a gitignored folder for users to submit their code should work fine.

[mystic sundial]

Is this concept of treating that folder as a package, and using some kind of reflection tools to get a list of existing modules? Or maybe doing a directory listing? I'm not sure if there's a "normal" way to solve this problem.

[tacit laurel]

directory listing will work

[mystic sundial]

So let's suppose I know that the plugins directory contains corvus03.py and corvus04.py, and I know each defines a class called decorator.

If I were doing this by hand, I would probably do
import plugins
D1 = plugins.corvus03.decorator()
D2 = plugins.corvus04.decorator()

But since I don't know what will exist when coding, is there a good way to go from

known_modules = [ 'corvus03', 'corvus04' ]

To a list of instantiated decorator classes?

[tacit laurel]

You should use importlib

alternatively, only import the __init__.py

[mystic sundial]

Isn't import part of importlib? Or are you suggesting something other than import?

[tacit laurel]

importlib.import_module("custom." + pluginname).decorator

[mystic sundial]

AH! I see, thank you!

[languid vigil]

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