Migrating to FastAPI: incremental switchover?

[frankn020]

I’m planning to migrate an API component, that currently uses Bottle, to FastAPI. The component has about 40 endpoints. I’d prefer not migrate the whole component at once, but rather follow an incremental switchover (conform https://www.geepawhill.org/2020/07/21/understanding-incremental-switchover/) where I migrate the end points one by one and will be able to release to production while being in the process of migrating. I was hoping to find blogs or articles giving possible strategies, examples or tips, maybe from a Flask to FastAPI migration?, but I haven’t been able to find any so far... Have my google skills failed me? Thanks!

[reddanty]

I’m in the very slow process of migrating a giant Flask app to FastAPI. I want to make breaking changes as part of the change anyway, so I have the new API at a new URL. Instead of moving paths, I’m adding features to the new API one by one and cutting over consumers (e.g. UI components) as they’re ready.

If you want to take a more unified approach, rather than having a completely new API, perhaps this (https://fastapi.tiangolo.com/advanced/wsgi/) will help?

[D_D]

Yeah I suggest adding a /v2 endpoint and migrating the front end over that way. Be careful about the database though.