grpclib: pure-Python gRPC implementation

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1. grpclib @vmagamedov, Evo
2. HTTP/2 protocol • Binary • Multiplexing • Bidirectional streams • Flow control • Headers compression
3. gRPC protocol = HTTP/2 + • Deadlines • Cancellation • Metadata (extensibility) • Declarative service definition language (.proto files) • Binary messages encoding (protobuf by default) • Streaming requests and responses • Authentication, Introspection, Load balancing x2
4. gRPC request: HEADERS :method = POST :scheme = http :path = /cafe.CoffeeMachine/MakeLatte :authority = cafe.svc:50051 content-type = application/grpc+proto te = trailers DATA ... length-prefixed message(s) ... DATA
5. gRPC response: HEADERS :status = 200 content-type = application/grpc+proto DATA ... length-prefixed message(s) ... DATA HEADERS # trailers grpc-status = 0 # OK
6. • grpcio by Google • Python 2.7, >=3.4 • threads • C++ based core: server and client • grpclib by Me & contributors • Python >= 3.5 • async/await • pure-Python, based on awesome hyper-h2 project
7. Definition syntax = "proto3"; package helloworld; service Greeter { rpc SayHello (HelloRequest) returns (HelloReply) {} } message HelloRequest { string name = 1; } message HelloReply { string message = 1; }
8. class Greeter(GreeterBase): async def SayHello(self, stream): request = await stream.recv_message() message = 'Hello, {}!'.format(request.name) await stream.send_message(HelloReply(message=message)) server = Server([Greeter()], loop=loop) loop.run_until_complete(server.start('127.0.0.1', 50051)) Server
9. channel = Channel('greeter.svc', 50051, loop=loop) stub = GreeterStub(channel) async def make_request(): response = await stub.SayHello(HelloRequest(name='World')) assert response.message == 'Hello, World!' Client
11. pip3 install grpclib Have fun! Come work with us (Evo) ;-)