Generate requirements.txt during build

[astrojarred]

As of now, we have to manually generate the requirements.txt that Vercel needs. Would be great to generate this at build time.

Things to check:

• Vercel doesn't have poetry installed by default. Are we allowed to install it, maybe in the mod.ts?
• It seems that maybe the API endpoints and pip installations happen before our Vite build step. To be checked.

Thanks to the work in #6 for inspiring this issue.

[Mohamed-Kaizen]

well...i was thinking maybe is better to generate requirements.txt when running dev server, with that the file will be ready for Vercel and people most likely will commit requirements.txt anyway.

But

i was thinking should we generate requirements.txt ?

Because currently we both assume and talk about poetry b/c we both used but in most case people use pip or other deps manger, so if we add some code that deps on poetry this will be unusable to some user(Like how i added that code in the PR 😅 ).

Assuming that we need to add this feature, we need to add an option in the plugin to ask the user
Do you want to generate requirements.txt ? if yes what deps manager you are using

[astrojarred]

Thanks for the input! It's true that not everyone uses poetry and we don't want to hardcode anything in there.

Perhaps we can do two things:

1. During the local build process (i.e. npm py-update phase), check if there is already a requirements.txt (from pip) and if not, check if there is a pyproject.toml and which poetry, and then automatically generate it if so.
2. During build on Vercel, check that there is actually a requirements.txt.

Only thing is, in both cases, some people might just use base python and therefore have no requirements.

[Mohamed-Kaizen]

During build on Vercel, check that there is actually a requirements.txt.

Does Vercel provide hook to edt the build ?

b/c you need to have the requirements.txt before pushing to Vercel, so...if there is no hook that let us intercept the Vercel build ..then the only option is to create the requirements.txt before pushing it .....

[astrojarred]

There is a hook to edit the build: buildCommand inside the vercel.json.

However, in my testing, Vercel does not recognize any requirements.txt generated during this step. Kind of the same problem with #8. Hopefully there's a way around this. Once I hear back from Vercel support I will update.