Add ASGI support

[simonw]

Zappa currently only supports WSGI.

ASGI is a new standard for Python web programming with deep support for Python 3 asyncio.

If Zappa added support for ASGI, projects written using the following frameworks would all become deployable using Zappa:

• Starlette and FastAPI
• Sanic
• Quart
• Datasette

The Mangum project already implements an ASGI handler for Lambda.

The work by @delijati in this fork seems to indicate that modifying Zappa to support ASGI via Mangum could be achieved with a relatively small change: https://github.com/Miserlou/Zappa/compare/master...delijati:master

[simonw]

ASGI is mentioned in #649 and #1896 but there's no single issue advocating for ASGI support to be added directly to Zappa, so I opened this one.

[bratao]

+1, FastAPI is growing fast and Zappa support to it would be awesome!

[gaurav386i]

+1, It would be great if support for ASGI will be added to new versions of Zappa .

[ArcLightSlavik]

Has anyone tried running it with gunicorn (WSGI) but using uvicorn workers (ASGI)? ie gunicorn -k uvicorn.workers.UvicornWorker

[ksingh7]

+1 , desperately need support for ASGI (FastAPI) in Zappa

[gaurav386i]

@ksingh7 we should open a feature request on new Zappa repo for ASGI support , FYI no activity on zappa repo from last couple of months, try some workaround with mangum . https://github.com/zappa/Zappa