Pure-Python gRPC implementation for asyncio

|project|_ |documentation|_ |version|_ |tag|_ |license|_

This project is based on hyper-h2_ and requires Python >= 3.6.

.. contents:: :local:

Example

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

Client
------

.. code-block:: python3

  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
------

.. code-block:: python3

  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

.. code-block:: console

$ pip3 install grpclib protobuf

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

.. code-block:: console

$ pip3 install --upgrade --pre grpclib

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

.. code-block:: console

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

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

.. code-block:: console

$ 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:

.. code-block:: console

  $ 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

.. _gRPC: http://www.grpc.io
.. _hyper-h2: https://github.com/python-hyper/hyper-h2
.. _grpcio: https://pypi.org/project/grpcio/
.. _Tox: https://tox.readthedocs.io/
.. _examples: https://github.com/vmagamedov/grpclib/tree/master/examples
.. |version| image:: https://img.shields.io/pypi/v/grpclib.svg?label=stable&color=blue
.. _version: https://pypi.org/project/grpclib/
.. |license| image:: https://img.shields.io/pypi/l/grpclib.svg?color=blue
.. _license: https://github.com/vmagamedov/grpclib/blob/master/LICENSE.txt
.. |tag| image:: https://img.shields.io/github/tag/vmagamedov/grpclib.svg?label=latest&color=blue
.. _tag: https://pypi.org/project/grpclib/#history
.. |project| image:: https://img.shields.io/badge/vmagamedov%2Fgrpclib-blueviolet.svg?logo=github&color=blue
.. _project: https://github.com/vmagamedov/grpclib
.. |documentation| image:: https://img.shields.io/badge/docs-grpclib.rtfd.io-blue.svg
.. _documentation: https://grpclib.readthedocs.io/en/latest/