Building Python services through gRPC

This presentations aims to show how to build services through gRPC in Python. It is presented 3 demos: A basic service covering all steps with Python+gRPC, a video streaming service and a TLS service. gRPC background, workflow, design and who is using are discussed as well.

Transcript

1. Gustavo Pantuza
2. Agenda • What is gRPC? • Background • Who is using • gRPC Workflow • Demo 0 • gRPC Design • Demo 1 • Security • Demo 2 • References
3. What is gRPC? "A high performance, open-source universal RPC framework" Project site: https://grpc.io Github: https://github.com/grpc
4. What is gRPC? • Remote Procedure Call • Type Safe • Polyglot • Binary message format • Multiplexed connections
5. What is gRPC? A bunch of best practices gathered together to build a simple distributed systems tool My personal opinion
6. What is gRPC?
7. Background • General-purpose RPC infrastructure called Stubby Open Source
8. Background Connect the large number of microservices running within and across our data centers
9. Background Cloud Native Computing Foundation To Host gRPC from Google
10. Who is using? "We’ve also seen a squishing and a narrowing of our latency windows" https://www.cncf.io/netflix-case-study/
11. Who is using? "Implementing GRPC/Telemetry on XR devices" https://community.cisco.com/t5/service-providers-documents/implementing-grpc-telemetry-on-xr-devices/ta-p/3393966
12. Who is using? "distribution layer is the first layer to communicate with other nodes" https://www.cockroachlabs.com/docs/stable/architecture/distribution-layer.html
13. Who is using? "more compact and efficiently serializable RPC payload" https://cilium.io/blog/grpc/
14. Who is using? "layers the best features of IDL-specified RPC onto a standard" https://linkerd.io/2017/01/11/http2-grpc-and-linkerd/#_ga=2.36853351.619173598.1561427300-69268088.1561427300
15. Who is using? https://stackshare.io/grpc
16. gRPC Workflow • The Message Protocol
17. gRPC Workflow • The Message Protocol Message definition protoc Compiler Python Go C++
18. syntax = "proto3"; package cheesefarm; Define the version and the package gRPC Workflow
19. syntax = "proto3"; package cheesefarm; message Cheese { int32 age = 1; CheeseType type = 2; } enum CheeseType { EMMENTAL = 0; BRIE = 1; PECORINO = 2; ROQUEFORT = 3; CANASTRA = 4; } message CheeseRequest { CheeseType type = 1; } Create your messages gRPC Workflow
20. syntax = "proto3"; package cheesefarm; message Cheese { int32 age = 1; CheeseType type = 2; } enum CheeseType { EMMENTAL = 0; BRIE = 1; PECORINO = 2; ROQUEFORT = 3; CANASTRA = 4; } message CheeseRequest { CheeseType type = 1; } service CheeseService { rpc Order(CheeseRequest) returns (Cheese); } Describe your Service interface gRPC Workflow
21. $> # Install gRPC libraries $> pip install grpcio $> pip install grpcio-tools Install gRPC Python libraries gRPC Workflow
22. $> # Compile gRPC files with Python $> # as target language in $> # the current directory $> python -m grpc_tools.protoc \ -I. \ --python_out=. \ --grpc_python_out=. \ cheese.proto Compilation time gRPC Workflow
23. $> # Two new files generated: $> # 1. cheese_pb2.py $> Protocol Buffer message $> # 2. cheese_pb2_grpc.py $> gRPC Service Client/Server $> ls cheese_pb2* cheese_pb2.py cheese_pb2_grpc.py Compilation Results gRPC Workflow
24. # Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT! import grpc import cheese_pb2 as cheese__pb2 class CheeseServiceStub(object): # missing associated documentation comment in .proto file pass def __init__(self, channel): """Constructor. Args: channel: A grpc.Channel. """ self.Order = channel.unary_unary( '/cheesefarm.CheeseService/Order', request_serializer=cheese__pb2.CheeseRequest.SerializeToString, response_deserializer=cheese__pb2.Cheese.FromString, ) class CheeseServiceServicer(object): # missing associated documentation comment in .proto file pass def Order(self, request, context): # missing associated documentation comment in .proto file pass context.set_code(grpc.StatusCode.UNIMPLEMENTED) context.set_details('Method not implemented!') raise NotImplementedError('Method not implemented!') Resulted code example gRPC Workflow
25. import grpc from concurrent import futures from time import sleep from random import randint # Imports all Protoc generated classes/code import cheese_pb2 import cheese_pb2_grpc class CheeseService(cheese_pb2_grpc.CheeseServiceServicer): """ Extends the auto generated CheeseServiceServicer class from Protoc compiler. In this class we implement the service layer code """ def Order(self, request, context): """ Simulates a Cheese Order load and returns a Cheese """ # Implementation here def main(): # gRPC server server = grpc.server(futures.ThreadPoolExecutor(max_workers=10)) # Binds our service implementation to a gRPC server through the # auto generated function add_CheeseServiceServicer_to_server cheese_pb2_grpc.add_CheeseServiceServicer_to_server(CheeseService(), server) print('Listening on localhost:4000') server.add_insecure_port('localhost:4000') server.start() # server.start() will not block, so we run a sleep-loop to keep # alive server alive until an interruption try: while True: sleep(60 * 60) # Each hour the loop continues except KeyboardInterrupt: server.stop(0) Server Implementation gRPC Workflow
26. from random import randint import grpc # Imports all Protoc generated classes/code import cheese_pb2 import cheese_pb2_grpc def main(): # gRPC channel channel = grpc.insecure_channel('localhost:4000') # create a stub (client) of our service stub = cheese_pb2_grpc.CheeseServiceStub(channel) while True: # Do cheeses orders cheese_request = cheese_pb2.CheeseRequest(type=randint(0, 4)) cheese = stub.Order(cheese_request) print("[gRPC] Received={0}".format( cheese_pb2.CheeseType.Name(cheese.type))) if __name__ == "__main__": main() Client Implementation gRPC Workflow
27. Demo 0 The Cheese Service
28. Demo 0
29. gRPC Design Http/2 by design • Binary payload • Multiplexed connections • Extensible
30. gRPC Design Streaming // From Server to Client rpc ListFeatures(Rectangle) returns (stream Feature) {} // From Client to Server rpc RecordRoute(stream Point) returns (RouteSummary) {} // Bidirectional rpc RouteChat(stream RouteNote) returns (stream RouteNote) {} The classic pair Send() and Recv() from socket library
31. gRPC Design Server streaming // From Server to Client rpc Watch(Match) returns (stream Video) {}
32. gRPC Design Client streaming // From client to Client rpc Upload(stream chunks) returns (Done) {}
33. Demo 1 The Soccer Match Service
34. syntax = "proto3"; package stream; message Match { string id = 1; } message Video { bytes data = 1; string data_type = 2; string data_shape = 3; } service Soccer { rpc Watch (Match) returns (stream Video) {} } Protocol Buffer Demo 1
35. class SoccerService(stream_pb2_grpc.SoccerServicer): """ Soccer Matches stream service based on gRPC """ def Watch(self, request, context): """ Returns a stream to a Match stream """ print("[gRPC] Match={0}".format(request.id)) file_path = "{0}.mp4".format(request.id) match = cv2.VideoCapture(file_path) while match.isOpened(): ret_val, frame = match.read() if not ret_val: break video = stream_pb2.Video( data=frame.tobytes(), data_type=frame.dtype.name, data_shape=str(frame.shape), ) yield video match.release() Server Implementation Demo 1
36. def main(): channel = grpc.insecure_channel('localhost:4000') stub = stream_pb2_grpc.SoccerStub(channel) match = stream_pb2.Match(id="KKNuUdn4wI4") iterator = stub.Watch(match) try: for video in iterator: frame = np.frombuffer( video.data, dtype=video.data_type ).reshape(literal_eval(video.data_shape)) cv2.imshow(match.id, frame) if cv2.waitKey(1) == 27: break # esc to quit cv2.destroyAllWindows() except grpc._channel._Rendezvous as err: print(err) sleep(3) Client Implementation Demo 1
37. Demo 1 The Soccer Match Service
38. gRPC Design Bidirectional streaming // Bidirectional rpc Chat(stream video) returns (stream video) {}
39. gRPC Design Blocking & Non-Blocking
40. gRPC Design Cancellation & Timeout
41. gRPC Design Pluggable Large distributed systems need: • Security • Health-checking • Load-balancing • Failover • Monitoring • Tracing • logging Python Interceptor example
42. gRPC Design Standardized Status Codes CODE NUMBER OK 0 CANCELLED 1 UNKNOWN 2 INVALID_ARGUMENT 3 ... ... https://github.com/grpc/grpc/blob/master/doc/statuscodes.md
43. gRPC security Supported and Authentication methods https://grpc.io/docs/guides/auth/
44. gRPC security TLS On the Server # gRPC server server = grpc.server(futures.ThreadPoolExecutor(max_workers=10)) cheese_pb2_grpc.add_CheeseServiceServicer_to_server(CheeseService(), server) # Load SSL files ssl_key = open("ssl/private.key", "rb").read() ssl_cert = open("ssl/cert.pem", "rb").read() credentials = grpc.ssl_server_credentials([(ssl_key, ssl_cert)]) print('Listening on localhost:4000') server.add_secure_port('localhost:4000', credentials) server.start()
45. gRPC security TLS On the Client # Load Certificate file trusted_cert = open("ssl/cert.pem", "rb").read() credentials = grpc.ssl_channel_credentials(root_certificates=trusted_cert) # gRPC channel channel = grpc.secure_channel('localhost:4000', credentials) # create a stub (client) of our service stub = cheese_pb2_grpc.CheeseServiceStub(channel)
46. Demo 2 The Cheese SECURE Service
47. gRPC References • Official project site • Official project Repositories • Awesome gRPC project • Official examples for other languages • Protocol Buffer official site
48. gRPC Python Examples • A simplified guide to gRPC in Python • gRPC Basics - Python • Python Quick Start • Python gRPC official example • Tutorial – Writing your first gRPC service in Python
49. Hey developers, please, play with me <3