Separate FunctionRegistry from FastAPI app

[chriso]

dispatch.fastapi.configure now returns a function registry that provides a decorator to register functions.

Previously, we were adding attributes to the FastAPI app:

import fastapi
from dispatch.fastapi import configure

app = fastapi.FastAPI()
configure(app, ...)

@app.dispatch_function
def my_function(input: Input) -> Output: ...

# dispatch a call a function:
app.dispatch(my_function, ...)

Now, the new Dispatch constructor returns a dispatch.Registry instance which provides the decorator:

import fastapi
from dispatch.fastapi import Dispatch

app = fastapi.FastAPI()
dispatch = Dispatch(app, ...)

@dispatch.function
def my_function(...): ...

# dispatch a call a function:
my_function.dispatch(...)

This is better because:

• it's fewer characters to type
• it works better with typing since the dispatch variable above has a concrete Registry type. Previously, tooling had trouble accessing and checking types since we were dynamically storing attributes on the fastapi.FastAPI() instance (app)
• it'll make it easier to add new integrations in future because we've separated the registration of functions (and dispatching of calls) from FastAPI

[achille-roussel]

I've been thinking about namings, what if we were following the same model as FastAPI and have the main object called Dispatch?

from fastapi import FastAPI
from dispatch.fastapi import Dispatch

app = FastAPI()
dispatch = Dispatch(app)

I don't know how the model scales to supporting other frameworks that may have different conventions, but maybe we'll just adopt a different convention for each so it feels more native.

[chriso]

That's cleaner, I like it. edit: updated