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
   

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

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

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

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

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6. What is gRPC?
   

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7. Background
   ● General-purpose RPC infrastructure called Stubby
   Open Source
   

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

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9. Background
   Cloud Native
   Computing
   Foundation To Host
   gRPC from Google
   

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

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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
    

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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
    

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

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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
    

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

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16. gRPC Workflow
    ● The Message Protocol
    

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

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

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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
    

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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
    

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

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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
    

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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
    

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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
    

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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
    

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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
    

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27. Demo 0
    The Cheese
    Service
    

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28. Demo 0
    

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

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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
    

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

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

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33. Demo 1
    The Soccer
    Match Service
    

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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
    

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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
    

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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
    

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37. Demo 1
    The Soccer
    Match Service
    

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

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39. gRPC Design
    Blocking & Non-Blocking
    

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40. gRPC Design
    Cancellation & Timeout
    

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

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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
    

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

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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()
    

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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)
    

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46. Demo 2
    The Cheese
    SECURE Service
    

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

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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
    

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49. Hey developers,
    please,
    play with me <3
    

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