Gustavo Pantuza 

Agenda ● What is gRPC? ● Background ● Who is using ● gRPC Workflow ● Demo 0 ● gRPC Design ● Demo 1 ● Security ● Demo 2 ● References 

What is gRPC? "A high performance, open-source universal RPC framework" Project site: https://grpc.io Github: https://github.com/grpc 

What is gRPC? ● Remote Procedure Call ● Type Safe ● Polyglot ● Binary message format ● Multiplexed connections 

What is gRPC? A bunch of best practices gathered together to build a simple distributed systems tool My personal opinion 

What is gRPC? 

Background ● General-purpose RPC infrastructure called Stubby Open Source 

Background Connect the large number of microservices running within and across our data centers 

Background Cloud Native Computing Foundation To Host gRPC from Google 

Who is using? "We’ve also seen a squishing and a narrowing of our latency windows" https://www.cncf.io/netflix-case-study/ 

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 

Who is using? "distribution layer is the first layer to communicate with other nodes" https://www.cockroachlabs.com/docs/stable/architecture/distribution-layer.html 

Who is using? "more compact and efficiently serializable RPC payload" https://cilium.io/blog/grpc/ 

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 

Who is using? https://stackshare.io/grpc 

gRPC Workflow ● The Message Protocol 

gRPC Workflow ● The Message Protocol Message definition protoc Compiler Python Go C++ 

syntax = "proto3"; package cheesefarm; Define the version and the package gRPC Workflow 

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 

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 

$> # Install gRPC libraries $> pip install grpcio $> pip install grpcio-tools Install gRPC Python libraries gRPC Workflow 

$> # 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 

$> # 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 

# 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 

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 

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 

Demo 0 The Cheese Service 

Demo 0 

gRPC Design Http/2 by design ● Binary payload ● Multiplexed connections ● Extensible 

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 

gRPC Design Server streaming // From Server to Client rpc Watch(Match) returns (stream Video) {} 

gRPC Design Client streaming // From client to Client rpc Upload(stream chunks) returns (Done) {} 

Demo 1 The Soccer Match Service 

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 

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 

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 

Demo 1 The Soccer Match Service 

gRPC Design Bidirectional streaming // Bidirectional rpc Chat(stream video) returns (stream video) {} 

gRPC Design Blocking & Non-Blocking 

gRPC Design Cancellation & Timeout 

gRPC Design Pluggable Large distributed systems need: ● Security ● Health-checking ● Load-balancing ● Failover ● Monitoring ● Tracing ● logging Python Interceptor example 

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 

gRPC security Supported and Authentication methods https://grpc.io/docs/guides/auth/ 

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() 

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) 

Demo 2 The Cheese SECURE Service 

gRPC References ● Official project site ● Official project Repositories ● Awesome gRPC project ● Official examples for other languages ● Protocol Buffer official site 

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 

Hey developers, please, play with me <3