To help you get started, we've collected the most common ways that grpclib is being used within popular public projects.

vmagamedov / grpclib / tests / test_protocol.py View on Github

await client_stream.send_request(create_headers(), _processor=client_proc)

    initial_window = server_h2c.local_settings.initial_window_size
    assert (client_h2c.local_flow_control_window(client_stream.id)
            == initial_window)

    # data should be bigger than window size
    data = b'0' * (initial_window + 1)
    size = len(data)

    # sending less than a full message
    await client_stream.send_data(data[:initial_window - 1])

    # let server process it's events
    server_processor = EventsProcessor(DummyHandler(), server_conn)
    to_server_transport.process(server_processor)

    # checking window size was decreased
    assert client_h2c.local_flow_control_window(client_stream.id) == 1

    # simulate that server is waiting for the size of a message and should
    # acknowledge that size as soon as it will be received
    server_stream, = server_processor.streams.values()
    recv_task = loop.create_task(server_stream.recv_data(size))
    await asyncio.wait([recv_task], timeout=.01)
    assert server_stream.buffer._acked_size == initial_window - 1

    # check that server acknowledged received partial data
    assert client_h2c.local_flow_control_window(client_stream.id) > 1

    # sending remaining data and recv_task should finish

View more ways to use grpclib

Pure-Python gRPC implementation for asyncio

_ _ _ _ _ _

This project is based on hyper-h2 and requires Python >= 3.7.

Example

See examples directory in the project's repository for all available examples.

Client

import asyncio

from grpclib.client import Channel

# generated by protoc
from .helloworld_pb2 import HelloRequest, HelloReply
from .helloworld_grpc import GreeterStub


async def main():
    async with Channel('127.0.0.1', 50051) as channel:
        greeter = GreeterStub(channel)

        reply = await greeter.SayHello(HelloRequest(name='Dr. Strange'))
        print(reply.message)


if __name__ == '__main__':
    asyncio.run(main())

Server

import asyncio

from grpclib.utils import graceful_exit
from grpclib.server import Server

# generated by protoc
from .helloworld_pb2 import HelloReply
from .helloworld_grpc import GreeterBase


class Greeter(GreeterBase):

    async def SayHello(self, stream):
        request = await stream.recv_message()
        message = f'Hello, {request.name}!'
        await stream.send_message(HelloReply(message=message))


async def main(*, host='127.0.0.1', port=50051):
    server = Server([Greeter()])
    # Note: graceful_exit isn't supported in Windows
    with graceful_exit([server]):
        await server.start(host, port)
        print(f'Serving on {host}:{port}')
        await server.wait_closed()


if __name__ == '__main__':
    asyncio.run(main())

Installation

$ pip3 install "grpclib[protobuf]"

Bug fixes and new features are frequently published via release candidates:

$ pip3 install --upgrade --pre "grpclib[protobuf]"

For the code generation you will also need a protoc compiler, which can be installed with protobuf system package:

$ brew install protobuf  # example for macOS users
$ protoc --version
libprotoc ...

Or you can use protoc compiler from the grpcio-tools Python package:

$ pip3 install grpcio-tools
$ python3 -m grpc_tools.protoc --version
libprotoc ...

Note: grpcio and grpcio-tools packages are not required in runtime, grpcio-tools package will be used only during code generation.

protoc plugin

In order to use this library you will have to generate special stub files using plugin provided, which can be used like this:

$ python3 -m grpc_tools.protoc -I. --python_out=. --grpclib_python_out=. helloworld/helloworld.proto
                                                    ^----- note -----^

This command will generate helloworld_pb2.py and helloworld_grpc.py files.

Plugin which implements --grpclib_python_out option should be available for the protoc compiler as the protoc-gen-grpclib_python executable which should be installed by pip into your $PATH during installation of the grpclib library.

Changed in v0.3.2: --python_grpc_out option was renamed into --grpclib_python_out.

Contributing

• Please submit an issue before working on a Pull Request
• Do not merge/squash/rebase your development branch while you work on a Pull Request, use rebase if this is really necessary
• You may use Tox in order to test and lint your changes, but it is Ok to rely on CI for this matter