Sonora

Sonora is a Python-first implementation of gRPC-Web built on top of standard Python APIs like WSGI and ASGI for easy integration.

Why?

Regular gRPC has a lot going for it but is awkward to use in some environments. gRPC-Web makes it easy to get gRPC working in environments that need HTTP/1.1 but the Google gRPC and gRPC-Web implementations don't like to coexist with your normal Python frameworks like Django or Flask. Sonora doesn't care what ioloop you use, this means you can run it along side any other Python web framework in the same application!

This makes it easy to

• Add gRPC to an existing code base.
• Run gRPC behind AWS and other HTTP/1.1 load balancers.
• Integrate with other ASGI frameworks like Channels, Starlette, Quart etc.
• Integrate with other WSGI frameworks like Flask, Django etc.

Sonora aims to be compatible with and tested against Google's grpc-web implementation in both text mode and binary mode.

The name Sonora was inspired by the Sonoran gopher snake.

How?

Sonora is designed to require minimal changes to an existing Python application.

Server

WSGI

Normally a WSGI application (such as your favourite Django app) will have a file somewhere named wsgi.py that gets your application setup and ready for your web server of choice. It will look something like this.

from django.core.wsgi import get_wsgi_application
application = get_wsgi_application()

To add Sonora's gRPC-Web capabilities to an application like the above all you need to do to enable it is this.

from django.core.wsgi import get_wsgi_application
from sonora.wsgi import grpcWSGI
import helloworld_pb2_grpc

# Setup your frameworks default WSGI app.

application = get_wsgi_application()

# Install the Sonora grpcWSGI middleware so we can handle requests to gRPC's paths.

application = grpcWSGI(application)

# Attach your gRPC server implementation.

helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), application)

And now you have a combined HTTP/1.1 Django + gRPC application all under a single port.

ASGI

For ASGI things are mostly the same, the example shown here integrates with Quart but it's more or less the same for other frameworks.

from sonora.asgi import grpcASGI
from quart import Quart
import helloworld_pb2_grpc

# Setup your frameworks default ASGI app.

application = Quart(__name__)

# Install the Sonora grpcASGI middleware so we can handle requests to gRPC's paths.

application.asgi_app = grpcASGI(application.asgi_app)

# Attach your gRPC server implementation.

helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), application.asgi_app)

And now you have a combined HTTP/1.1 Quart + gRPC application all under a single port.

Clients

Sonora provides both regular sync and aiohttp based async clients.

Requests (Sync)

Instead of using gRPCs native grpc.insecure_channel API we have sonora.client.insecure_web_channel instead which provides a requests powered client channel to a gRPC-Web server. e.g.

    import sonora.client

    with sonora.client.insecure_web_channel(
        f"http://localhost:8080"
    ) as channel:
        stub = helloworld_pb2_grpc.GreeterStub(channel)
        print(stub.SayHello("world"))

Aiohttp (Async)

Instead of grpc.aio.insecure_channel we have sonora.aio.insecure_web_channel which provides an aiohttp based asyncio compatible client for gRPC-Web. e.g.

    import sonora.aio

    async with sonora.aio.insecure_web_channel(
        f"http://localhost:8080"
    ) as channel:
        stub = helloworld_pb2_grpc.GreeterStub(channel)
        print(await stub.SayHello("world"))

        stub = helloworld_pb2_grpc.GreeterStub(channel)
        async for response in stub.SayHelloSlowly("world"):
            print(response)

This also supports the new streaming response API introduced by gRFC L58

    import sonora.aio

    async with sonora.aio.insecure_web_channel(
        f"http://localhost:8080"
    ) as channel:
        stub = helloworld_pb2_grpc.GreeterStub(channel)
        async with stub.SayHelloSlowly("world") as response:
            print(await response.read())