grpc例(2)

76769 ワード

python
コードの生成
インストールgrpc_python_plugin:
  • sudo pip3 install grpcio
  •  protoc -I . --python_out=. --grpc_out=. --plugin=protoc-gen-grpc=/usr/bin/grpc_python_plugin route_guide.proto
    

    注意:--plugin=protoc-gen-grpc='which grpc_python_plugin'が見つからないので指定したパスで
    ファイルの生成:
  • route_guide_pb2_grpc.py
  • route_guide_pb2.py

  • route_guide_pb2.py
    # Generated by the protocol buffer compiler.  DO NOT EDIT!
    # source: route_guide.proto
    
    import sys
    _b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
    from google.protobuf import descriptor as _descriptor
    from google.protobuf import message as _message
    from google.protobuf import reflection as _reflection
    from google.protobuf import symbol_database as _symbol_database
    from google.protobuf import descriptor_pb2
    # @@protoc_insertion_point(imports)
    
    _sym_db = _symbol_database.Default()
    
    
    
    
    DESCRIPTOR = _descriptor.FileDescriptor(
      name='route_guide.proto',
      package='routeguide',
      syntax='proto3',
      serialized_pb=_b('
    \x11route_guide.proto\x12
    routeguide\",
    \x05Point\x12\x10
    \x08latitude\x18\x01 \x01(\x05\x12\x11
    \tlongitude\x18\x02 \x01(\x05\"I
    \tRectangle\x12\x1d
    \x02lo\x18\x01 \x01(\x0b\x32\x11.routeguide.Point\x12\x1d
    \x02hi\x18\x02 \x01(\x0b\x32\x11.routeguide.Point\"
    \x0cListFeatures\x12\x15.routeguide.Rectangle\x1a\x13.routeguide.Feature\"\x00\x30\x01\x12>
    \x0bRecordRoute\x12\x11.routeguide.Point\x1a\x18.routeguide.RouteSummary\"\x00(\x01\x12?
    \tRouteChat\x12\x15.routeguide.RouteNote\x1a\x15.routeguide.RouteNote\"\x00(\x01\x30\x01\x42\x36
    \x1bio.grpc.examples.routeguideB\x0fRouteGuideProtoP\x01\xa2\x02\x03RTGb\x06proto3') ) _sym_db.RegisterFileDescriptor(DESCRIPTOR) _POINT = _descriptor.Descriptor( name='Point', full_name='routeguide.Point', filename=None, file=DESCRIPTOR, containing_type=None, fields=[ _descriptor.FieldDescriptor( name='latitude', full_name='routeguide.Point.latitude', index=0, number=1, type=5, cpp_type=1, label=1, has_default_value=False, default_value=0, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), _descriptor.FieldDescriptor( name='longitude', full_name='routeguide.Point.longitude', index=1, number=2, type=5, cpp_type=1, label=1, has_default_value=False, default_value=0, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), ], extensions=[ ], nested_types=[], enum_types=[ ], options=None, is_extendable=False, syntax='proto3', extension_ranges=[], oneofs=[ ], serialized_start=33, serialized_end=77, ) _RECTANGLE = _descriptor.Descriptor( name='Rectangle', full_name='routeguide.Rectangle', filename=None, file=DESCRIPTOR, containing_type=None, fields=[ _descriptor.FieldDescriptor( name='lo', full_name='routeguide.Rectangle.lo', index=0, number=1, type=11, cpp_type=10, label=1, has_default_value=False, default_value=None, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), _descriptor.FieldDescriptor( name='hi', full_name='routeguide.Rectangle.hi', index=1, number=2, type=11, cpp_type=10, label=1, has_default_value=False, default_value=None, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), ], extensions=[ ], nested_types=[], enum_types=[ ], options=None, is_extendable=False, syntax='proto3', extension_ranges=[], oneofs=[ ], serialized_start=79, serialized_end=152, ) _FEATURE = _descriptor.Descriptor( name='Feature', full_name='routeguide.Feature', filename=None, file=DESCRIPTOR, containing_type=None, fields=[ _descriptor.FieldDescriptor( name='name', full_name='routeguide.Feature.name', index=0, number=1, type=9, cpp_type=9, label=1, has_default_value=False, default_value=_b("").decode('utf-8'), message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), _descriptor.FieldDescriptor( name='location', full_name='routeguide.Feature.location', index=1, number=2, type=11, cpp_type=10, label=1, has_default_value=False, default_value=None, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), ], extensions=[ ], nested_types=[], enum_types=[ ], options=None, is_extendable=False, syntax='proto3', extension_ranges=[], oneofs=[ ], serialized_start=154, serialized_end=214, ) _ROUTENOTE = _descriptor.Descriptor( name='RouteNote', full_name='routeguide.RouteNote', filename=None, file=DESCRIPTOR, containing_type=None, fields=[ _descriptor.FieldDescriptor( name='location', full_name='routeguide.RouteNote.location', index=0, number=1, type=11, cpp_type=10, label=1, has_default_value=False, default_value=None, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), _descriptor.FieldDescriptor( name='message', full_name='routeguide.RouteNote.message', index=1, number=2, type=9, cpp_type=9, label=1, has_default_value=False, default_value=_b("").decode('utf-8'), message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), ], extensions=[ ], nested_types=[], enum_types=[ ], options=None, is_extendable=False, syntax='proto3', extension_ranges=[], oneofs=[ ], serialized_start=216, serialized_end=281, ) _ROUTESUMMARY = _descriptor.Descriptor( name='RouteSummary', full_name='routeguide.RouteSummary', filename=None, file=DESCRIPTOR, containing_type=None, fields=[ _descriptor.FieldDescriptor( name='point_count', full_name='routeguide.RouteSummary.point_count', index=0, number=1, type=5, cpp_type=1, label=1, has_default_value=False, default_value=0, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), _descriptor.FieldDescriptor( name='feature_count', full_name='routeguide.RouteSummary.feature_count', index=1, number=2, type=5, cpp_type=1, label=1, has_default_value=False, default_value=0, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), _descriptor.FieldDescriptor( name='distance', full_name='routeguide.RouteSummary.distance', index=2, number=3, type=5, cpp_type=1, label=1, has_default_value=False, default_value=0, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), _descriptor.FieldDescriptor( name='elapsed_time', full_name='routeguide.RouteSummary.elapsed_time', index=3, number=4, type=5, cpp_type=1, label=1, has_default_value=False, default_value=0, message_type=None, enum_type=None, containing_type=None, is_extension=False, extension_scope=None, options=None), ], extensions=[ ], nested_types=[], enum_types=[ ], options=None, is_extendable=False, syntax='proto3', extension_ranges=[], oneofs=[ ], serialized_start=283, serialized_end=381, ) _RECTANGLE.fields_by_name['lo'].message_type = _POINT _RECTANGLE.fields_by_name['hi'].message_type = _POINT _FEATURE.fields_by_name['location'].message_type = _POINT _ROUTENOTE.fields_by_name['location'].message_type = _POINT DESCRIPTOR.message_types_by_name['Point'] = _POINT DESCRIPTOR.message_types_by_name['Rectangle'] = _RECTANGLE DESCRIPTOR.message_types_by_name['Feature'] = _FEATURE DESCRIPTOR.message_types_by_name['RouteNote'] = _ROUTENOTE DESCRIPTOR.message_types_by_name['RouteSummary'] = _ROUTESUMMARY Point = _reflection.GeneratedProtocolMessageType('Point', (_message.Message,), dict( DESCRIPTOR = _POINT, __module__ = 'route_guide_pb2' # @@protoc_insertion_point(class_scope:routeguide.Point) )) _sym_db.RegisterMessage(Point) Rectangle = _reflection.GeneratedProtocolMessageType('Rectangle', (_message.Message,), dict( DESCRIPTOR = _RECTANGLE, __module__ = 'route_guide_pb2' # @@protoc_insertion_point(class_scope:routeguide.Rectangle) )) _sym_db.RegisterMessage(Rectangle) Feature = _reflection.GeneratedProtocolMessageType('Feature', (_message.Message,), dict( DESCRIPTOR = _FEATURE, __module__ = 'route_guide_pb2' # @@protoc_insertion_point(class_scope:routeguide.Feature) )) _sym_db.RegisterMessage(Feature) RouteNote = _reflection.GeneratedProtocolMessageType('RouteNote', (_message.Message,), dict( DESCRIPTOR = _ROUTENOTE, __module__ = 'route_guide_pb2' # @@protoc_insertion_point(class_scope:routeguide.RouteNote) )) _sym_db.RegisterMessage(RouteNote) RouteSummary = _reflection.GeneratedProtocolMessageType('RouteSummary', (_message.Message,), dict( DESCRIPTOR = _ROUTESUMMARY, __module__ = 'route_guide_pb2' # @@protoc_insertion_point(class_scope:routeguide.RouteSummary) )) _sym_db.RegisterMessage(RouteSummary) DESCRIPTOR.has_options = True DESCRIPTOR._options = _descriptor._ParseOptions(descriptor_pb2.FileOptions(), _b('
    \033io.grpc.examples.routeguideB\017RouteGuideProtoP\001\242\002\003RTG')) try: # THESE ELEMENTS WILL BE DEPRECATED. # Please use the generated *_pb2_grpc.py files instead. import grpc from grpc.beta import implementations as beta_implementations from grpc.beta import interfaces as beta_interfaces from grpc.framework.common import cardinality from grpc.framework.interfaces.face import utilities as face_utilities class RouteGuideStub(object): """Interface exported by the server. """ def __init__(self, channel): """Constructor. Args: channel: A grpc.Channel. """ self.GetFeature = channel.unary_unary( '/routeguide.RouteGuide/GetFeature', request_serializer=Point.SerializeToString, response_deserializer=Feature.FromString, ) self.ListFeatures = channel.unary_stream( '/routeguide.RouteGuide/ListFeatures', request_serializer=Rectangle.SerializeToString, response_deserializer=Feature.FromString, ) self.RecordRoute = channel.stream_unary( '/routeguide.RouteGuide/RecordRoute', request_serializer=Point.SerializeToString, response_deserializer=RouteSummary.FromString, ) self.RouteChat = channel.stream_stream( '/routeguide.RouteGuide/RouteChat', request_serializer=RouteNote.SerializeToString, response_deserializer=RouteNote.FromString, ) class RouteGuideServicer(object): """Interface exported by the server. """ def GetFeature(self, request, context): """A simple RPC. Obtains the feature at a given position. A feature with an empty name is returned if there's no feature at the given position. """ context.set_code(grpc.StatusCode.UNIMPLEMENTED) context.set_details('Method not implemented!') raise NotImplementedError('Method not implemented!') def ListFeatures(self, request, context): """A server-to-client streaming RPC. Obtains the Features available within the given Rectangle. Results are streamed rather than returned at once (e.g. in a response message with a repeated field), as the rectangle may cover a large area and contain a huge number of features. """ context.set_code(grpc.StatusCode.UNIMPLEMENTED) context.set_details('Method not implemented!') raise NotImplementedError('Method not implemented!') def RecordRoute(self, request_iterator, context): """A client-to-server streaming RPC. Accepts a stream of Points on a route being traversed, returning a RouteSummary when traversal is completed. """ context.set_code(grpc.StatusCode.UNIMPLEMENTED) context.set_details('Method not implemented!') raise NotImplementedError('Method not implemented!') def RouteChat(self, request_iterator, context): """A Bidirectional streaming RPC. Accepts a stream of RouteNotes sent while a route is being traversed, while receiving other RouteNotes (e.g. from other users). """ context.set_code(grpc.StatusCode.UNIMPLEMENTED) context.set_details('Method not implemented!') raise NotImplementedError('Method not implemented!') def add_RouteGuideServicer_to_server(servicer, server): rpc_method_handlers = { 'GetFeature': grpc.unary_unary_rpc_method_handler( servicer.GetFeature, request_deserializer=Point.FromString, response_serializer=Feature.SerializeToString, ), 'ListFeatures': grpc.unary_stream_rpc_method_handler( servicer.ListFeatures, request_deserializer=Rectangle.FromString, response_serializer=Feature.SerializeToString, ), 'RecordRoute': grpc.stream_unary_rpc_method_handler( servicer.RecordRoute, request_deserializer=Point.FromString, response_serializer=RouteSummary.SerializeToString, ), 'RouteChat': grpc.stream_stream_rpc_method_handler( servicer.RouteChat, request_deserializer=RouteNote.FromString, response_serializer=RouteNote.SerializeToString, ), } generic_handler = grpc.method_handlers_generic_handler( 'routeguide.RouteGuide', rpc_method_handlers) server.add_generic_rpc_handlers((generic_handler,)) class BetaRouteGuideServicer(object): """The Beta API is deprecated for 0.15.0 and later. It is recommended to use the GA API (classes and functions in this file not marked beta) for all further purposes. This class was generated only to ease transition from grpcio<0.15.0 to grpcio>=0.15.0.""" """Interface exported by the server. """ def GetFeature(self, request, context): """A simple RPC. Obtains the feature at a given position. A feature with an empty name is returned if there's no feature at the given position. """ context.code(beta_interfaces.StatusCode.UNIMPLEMENTED) def ListFeatures(self, request, context): """A server-to-client streaming RPC. Obtains the Features available within the given Rectangle. Results are streamed rather than returned at once (e.g. in a response message with a repeated field), as the rectangle may cover a large area and contain a huge number of features. """ context.code(beta_interfaces.StatusCode.UNIMPLEMENTED) def RecordRoute(self, request_iterator, context): """A client-to-server streaming RPC. Accepts a stream of Points on a route being traversed, returning a RouteSummary when traversal is completed. """ context.code(beta_interfaces.StatusCode.UNIMPLEMENTED) def RouteChat(self, request_iterator, context): """A Bidirectional streaming RPC. Accepts a stream of RouteNotes sent while a route is being traversed, while receiving other RouteNotes (e.g. from other users). """ context.code(beta_interfaces.StatusCode.UNIMPLEMENTED) class BetaRouteGuideStub(object): """The Beta API is deprecated for 0.15.0 and later. It is recommended to use the GA API (classes and functions in this file not marked beta) for all further purposes. This class was generated only to ease transition from grpcio<0.15.0 to grpcio>=0.15.0.""" """Interface exported by the server. """ def GetFeature(self, request, timeout, metadata=None, with_call=False, protocol_options=None): """A simple RPC. Obtains the feature at a given position. A feature with an empty name is returned if there's no feature at the given position. """ raise NotImplementedError() GetFeature.future = None def ListFeatures(self, request, timeout, metadata=None, with_call=False, protocol_options=None): """A server-to-client streaming RPC. Obtains the Features available within the given Rectangle. Results are streamed rather than returned at once (e.g. in a response message with a repeated field), as the rectangle may cover a large area and contain a huge number of features. """ raise NotImplementedError() def RecordRoute(self, request_iterator, timeout, metadata=None, with_call=False, protocol_options=None): """A client-to-server streaming RPC. Accepts a stream of Points on a route being traversed, returning a RouteSummary when traversal is completed. """ raise NotImplementedError() RecordRoute.future = None def RouteChat(self, request_iterator, timeout, metadata=None, with_call=False, protocol_options=None): """A Bidirectional streaming RPC. Accepts a stream of RouteNotes sent while a route is being traversed, while receiving other RouteNotes (e.g. from other users). """ raise NotImplementedError() def beta_create_RouteGuide_server(servicer, pool=None, pool_size=None, default_timeout=None, maximum_timeout=None): """The Beta API is deprecated for 0.15.0 and later. It is recommended to use the GA API (classes and functions in this file not marked beta) for all further purposes. This function was generated only to ease transition from grpcio<0.15.0 to grpcio>=0.15.0""" request_deserializers = { ('routeguide.RouteGuide', 'GetFeature'): Point.FromString, ('routeguide.RouteGuide', 'ListFeatures'): Rectangle.FromString, ('routeguide.RouteGuide', 'RecordRoute'): Point.FromString, ('routeguide.RouteGuide', 'RouteChat'): RouteNote.FromString, } response_serializers = { ('routeguide.RouteGuide', 'GetFeature'): Feature.SerializeToString, ('routeguide.RouteGuide', 'ListFeatures'): Feature.SerializeToString, ('routeguide.RouteGuide', 'RecordRoute'): RouteSummary.SerializeToString, ('routeguide.RouteGuide', 'RouteChat'): RouteNote.SerializeToString, } method_implementations = { ('routeguide.RouteGuide', 'GetFeature'): face_utilities.unary_unary_inline(servicer.GetFeature), ('routeguide.RouteGuide', 'ListFeatures'): face_utilities.unary_stream_inline(servicer.ListFeatures), ('routeguide.RouteGuide', 'RecordRoute'): face_utilities.stream_unary_inline(servicer.RecordRoute), ('routeguide.RouteGuide', 'RouteChat'): face_utilities.stream_stream_inline(servicer.RouteChat), } server_options = beta_implementations.server_options(request_deserializers=request_deserializers, response_serializers=response_serializers, thread_pool=pool, thread_pool_size=pool_size, default_timeout=default_timeout, maximum_timeout=maximum_timeout) return beta_implementations.server(method_implementations, options=server_options) def beta_create_RouteGuide_stub(channel, host=None, metadata_transformer=None, pool=None, pool_size=None): """The Beta API is deprecated for 0.15.0 and later. It is recommended to use the GA API (classes and functions in this file not marked beta) for all further purposes. This function was generated only to ease transition from grpcio<0.15.0 to grpcio>=0.15.0""" request_serializers = { ('routeguide.RouteGuide', 'GetFeature'): Point.SerializeToString, ('routeguide.RouteGuide', 'ListFeatures'): Rectangle.SerializeToString, ('routeguide.RouteGuide', 'RecordRoute'): Point.SerializeToString, ('routeguide.RouteGuide', 'RouteChat'): RouteNote.SerializeToString, } response_deserializers = { ('routeguide.RouteGuide', 'GetFeature'): Feature.FromString, ('routeguide.RouteGuide', 'ListFeatures'): Feature.FromString, ('routeguide.RouteGuide', 'RecordRoute'): RouteSummary.FromString, ('routeguide.RouteGuide', 'RouteChat'): RouteNote.FromString, } cardinalities = { 'GetFeature': cardinality.Cardinality.UNARY_UNARY, 'ListFeatures': cardinality.Cardinality.UNARY_STREAM, 'RecordRoute': cardinality.Cardinality.STREAM_UNARY, 'RouteChat': cardinality.Cardinality.STREAM_STREAM, } stub_options = beta_implementations.stub_options(host=host, metadata_transformer=metadata_transformer, request_serializers=request_serializers, response_deserializers=response_deserializers, thread_pool=pool, thread_pool_size=pool_size) return beta_implementations.dynamic_stub(channel, 'routeguide.RouteGuide', cardinalities, options=stub_options) except ImportError: pass # @@protoc_insertion_point(module_scope)

    route_guide_pb2_grpc.py
    # Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT!
    import grpc
    
    import route_guide_pb2 as route__guide__pb2
    
    
    class RouteGuideStub(object):
      """Interface exported by the server.
      """
    
      def __init__(self, channel):
        """Constructor.
    
        Args:
          channel: A grpc.Channel.
        """
        self.GetFeature = channel.unary_unary(
            '/routeguide.RouteGuide/GetFeature',
            request_serializer=route__guide__pb2.Point.SerializeToString,
            response_deserializer=route__guide__pb2.Feature.FromString,
            )
        self.ListFeatures = channel.unary_stream(
            '/routeguide.RouteGuide/ListFeatures',
            request_serializer=route__guide__pb2.Rectangle.SerializeToString,
            response_deserializer=route__guide__pb2.Feature.FromString,
            )
        self.RecordRoute = channel.stream_unary(
            '/routeguide.RouteGuide/RecordRoute',
            request_serializer=route__guide__pb2.Point.SerializeToString,
            response_deserializer=route__guide__pb2.RouteSummary.FromString,
            )
        self.RouteChat = channel.stream_stream(
            '/routeguide.RouteGuide/RouteChat',
            request_serializer=route__guide__pb2.RouteNote.SerializeToString,
            response_deserializer=route__guide__pb2.RouteNote.FromString,
            )
    
    
    class RouteGuideServicer(object):
      """Interface exported by the server.
      """
    
      def GetFeature(self, request, context):
        """A simple RPC.
    
        Obtains the feature at a given position.
    
        A feature with an empty name is returned if there's no feature at the given
        position.
        """
        context.set_code(grpc.StatusCode.UNIMPLEMENTED)
        context.set_details('Method not implemented!')
        raise NotImplementedError('Method not implemented!')
    
      def ListFeatures(self, request, context):
        """A server-to-client streaming RPC.
    
        Obtains the Features available within the given Rectangle.  Results are
        streamed rather than returned at once (e.g. in a response message with a
        repeated field), as the rectangle may cover a large area and contain a
        huge number of features.
        """
        context.set_code(grpc.StatusCode.UNIMPLEMENTED)
        context.set_details('Method not implemented!')
        raise NotImplementedError('Method not implemented!')
    
      def RecordRoute(self, request_iterator, context):
        """A client-to-server streaming RPC.
    
        Accepts a stream of Points on a route being traversed, returning a
        RouteSummary when traversal is completed.
        """
        context.set_code(grpc.StatusCode.UNIMPLEMENTED)
        context.set_details('Method not implemented!')
        raise NotImplementedError('Method not implemented!')
    
      def RouteChat(self, request_iterator, context):
        """A Bidirectional streaming RPC.
    
        Accepts a stream of RouteNotes sent while a route is being traversed,
        while receiving other RouteNotes (e.g. from other users).
        """
        context.set_code(grpc.StatusCode.UNIMPLEMENTED)
        context.set_details('Method not implemented!')
        raise NotImplementedError('Method not implemented!')
    
    
    def add_RouteGuideServicer_to_server(servicer, server):
      rpc_method_handlers = {
          'GetFeature': grpc.unary_unary_rpc_method_handler(
              servicer.GetFeature,
              request_deserializer=route__guide__pb2.Point.FromString,
              response_serializer=route__guide__pb2.Feature.SerializeToString,
          ),
          'ListFeatures': grpc.unary_stream_rpc_method_handler(
              servicer.ListFeatures,
              request_deserializer=route__guide__pb2.Rectangle.FromString,
              response_serializer=route__guide__pb2.Feature.SerializeToString,
          ),
          'RecordRoute': grpc.stream_unary_rpc_method_handler(
              servicer.RecordRoute,
              request_deserializer=route__guide__pb2.Point.FromString,
              response_serializer=route__guide__pb2.RouteSummary.SerializeToString,
          ),
          'RouteChat': grpc.stream_stream_rpc_method_handler(
              servicer.RouteChat,
              request_deserializer=route__guide__pb2.RouteNote.FromString,
              response_serializer=route__guide__pb2.RouteNote.SerializeToString,
          ),
      }
      generic_handler = grpc.method_handlers_generic_handler(
          'routeguide.RouteGuide', rpc_method_handlers)
      server.add_generic_rpc_handlers((generic_handler,))
    
    

    サーバの作成
    from concurrent import futures
    import time
    import math
    import logging
    
    import grpc
    
    import route_guide_pb2
    import route_guide_pb2_grpc
    import route_guide_resources
    
    _ONE_DAY_IN_SECONDS = 60 * 60 * 24
    
    
    def get_feature(feature_db, point):
        """Returns Feature at given location or None."""
        for feature in feature_db:
            if feature.location == point:
                return feature
        return None
    
    
    def get_distance(start, end):
        """Distance between two points."""
        coord_factor = 10000000.0
        lat_1 = start.latitude / coord_factor
        lat_2 = end.latitude / coord_factor
        lon_1 = start.longitude / coord_factor
        lon_2 = end.longitude / coord_factor
        lat_rad_1 = math.radians(lat_1)
        lat_rad_2 = math.radians(lat_2)
        delta_lat_rad = math.radians(lat_2 - lat_1)
        delta_lon_rad = math.radians(lon_2 - lon_1)
    
        # Formula is based on http://mathforum.org/library/drmath/view/51879.html
        a = (pow(math.sin(delta_lat_rad / 2), 2) +
             (math.cos(lat_rad_1) * math.cos(lat_rad_2) * pow(
                 math.sin(delta_lon_rad / 2), 2)))
        c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
        R = 6371000
        # metres
        return R * c
    
    
    class RouteGuideServicer(route_guide_pb2_grpc.RouteGuideServicer):
        """Provides methods that implement functionality of route guide server."""
    
        def __init__(self):
            self.db = route_guide_resources.read_route_guide_database()
    
        def GetFeature(self, request, context):
            feature = get_feature(self.db, request)
            if feature is None:
                return route_guide_pb2.Feature(name="", location=request)
            else:
                return feature
    
        def ListFeatures(self, request, context):
            left = min(request.lo.longitude, request.hi.longitude)
            right = max(request.lo.longitude, request.hi.longitude)
            top = max(request.lo.latitude, request.hi.latitude)
            bottom = min(request.lo.latitude, request.hi.latitude)
            for feature in self.db:
                if (feature.location.longitude >= left and
                        feature.location.longitude <= right and
                        feature.location.latitude >= bottom and
                        feature.location.latitude <= top):
                    yield feature
    
        def RecordRoute(self, request_iterator, context):
            point_count = 0
            feature_count = 0
            distance = 0.0
            prev_point = None
    
            start_time = time.time()
            for point in request_iterator:
                point_count += 1
                if get_feature(self.db, point):
                    feature_count += 1
                if prev_point:
                    distance += get_distance(prev_point, point)
                prev_point = point
    
            elapsed_time = time.time() - start_time
            return route_guide_pb2.RouteSummary(
                point_count=point_count,
                feature_count=feature_count,
                distance=int(distance),
                elapsed_time=int(elapsed_time))
    
        def RouteChat(self, request_iterator, context):
            prev_notes = []
            for new_note in request_iterator:
                for prev_note in prev_notes:
                    if prev_note.location == new_note.location:
                        yield prev_note
                prev_notes.append(new_note)
    
    
    def serve():
        server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
        route_guide_pb2_grpc.add_RouteGuideServicer_to_server(
            RouteGuideServicer(), server)
        server.add_insecure_port('[::]:50051')
        server.start()
        try:
            while True:
                time.sleep(_ONE_DAY_IN_SECONDS)
        except KeyboardInterrupt:
            server.stop(0)
    
    
    if __name__ == '__main__':
        logging.basicConfig()
        serve()
    

    クライアントの作成
    from __future__ import print_function
    
    import random
    import logging
    
    import grpc
    
    import route_guide_pb2
    import route_guide_pb2_grpc
    import route_guide_resources
    
    
    def make_route_note(message, latitude, longitude):
        return route_guide_pb2.RouteNote(
            message=message,
            location=route_guide_pb2.Point(latitude=latitude, longitude=longitude))
    
    
    def guide_get_one_feature(stub, point):
        feature = stub.GetFeature(point)
        if not feature.location:
            print("Server returned incomplete feature")
            return
    
        if feature.name:
            print("Feature called %s at %s" % (feature.name, feature.location))
        else:
            print("Found no feature at %s" % feature.location)
    
    
    def guide_get_feature(stub):
        guide_get_one_feature(stub,
                              route_guide_pb2.Point(
                                  latitude=409146138, longitude=-746188906))
        guide_get_one_feature(stub, route_guide_pb2.Point(latitude=0, longitude=0))
    
    
    def guide_list_features(stub):
        rectangle = route_guide_pb2.Rectangle(
            lo=route_guide_pb2.Point(latitude=400000000, longitude=-750000000),
            hi=route_guide_pb2.Point(latitude=420000000, longitude=-730000000))
        print("Looking for features between 40, -75 and 42, -73")
    
        features = stub.ListFeatures(rectangle)
    
        for feature in features:
            print("Feature called %s at %s" % (feature.name, feature.location))
    
    
    def generate_route(feature_list):
        for _ in range(0, 10):
            random_feature = feature_list[random.randint(0, len(feature_list) - 1)]
            print("Visiting point %s" % random_feature.location)
            yield random_feature.location
    
    
    def guide_record_route(stub):
        feature_list = route_guide_resources.read_route_guide_database()
    
        route_iterator = generate_route(feature_list)
        route_summary = stub.RecordRoute(route_iterator)
        print("Finished trip with %s points " % route_summary.point_count)
        print("Passed %s features " % route_summary.feature_count)
        print("Travelled %s meters " % route_summary.distance)
        print("It took %s seconds " % route_summary.elapsed_time)
    
    
    def generate_messages():
        messages = [
            make_route_note("First message", 0, 0),
            make_route_note("Second message", 0, 1),
            make_route_note("Third message", 1, 0),
            make_route_note("Fourth message", 0, 0),
            make_route_note("Fifth message", 1, 0),
        ]
        for msg in messages:
            print("Sending %s at %s" % (msg.message, msg.location))
            yield msg
    
    
    def guide_route_chat(stub):
        responses = stub.RouteChat(generate_messages())
        for response in responses:
            print("Received message %s at %s" % (response.message,
                                                 response.location))
    
    
    def run():
        # NOTE(gRPC Python Team): .close() is possible on a channel and should be
        # used in circumstances in which the with statement does not fit the needs
        # of the code.
        with grpc.insecure_channel('localhost:50051') as channel:
            stub = route_guide_pb2_grpc.RouteGuideStub(channel)
            print("-------------- GetFeature --------------")
            guide_get_feature(stub)
            print("-------------- ListFeatures --------------")
            guide_list_features(stub)
            print("-------------- RecordRoute --------------")
            guide_record_route(stub)
            print("-------------- RouteChat --------------")
            guide_route_chat(stub)
    
    
    if __name__ == '__main__':
        logging.basicConfig()
        run()
    

    go
    クライアントとサーバ側コードの生成
    go get -u github.com/golang/protobuf/proto
    go get -u github.com/golang/protobuf/protoc-gen-go
    
     vim  /etc/profile   
        export GOPATH=/root/go
        export PATH=$PATH:$GOPATH/bin
    source /etc/profile
    
    protoc -I . --go_out=. route_guide.proto
    

    コードの生成
    route_guide.pb.go
    // Code generated by protoc-gen-go. DO NOT EDIT.
    // source: route_guide.proto
    
    package routeguide
    
    import (
    	fmt "fmt"
    	proto "github.com/golang/protobuf/proto"
    	math "math"
    )
    
    // Reference imports to suppress errors if they are not otherwise used.
    var _ = proto.Marshal
    var _ = fmt.Errorf
    var _ = math.Inf
    
    // This is a compile-time assertion to ensure that this generated file
    // is compatible with the proto package it is being compiled against.
    // A compilation error at this line likely means your copy of the
    // proto package needs to be updated.
    const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
    
    // Points are represented as latitude-longitude pairs in the E7 representation
    // (degrees multiplied by 10**7 and rounded to the nearest integer).
    // Latitudes should be in the range +/- 90 degrees and longitude should be in
    // the range +/- 180 degrees (inclusive).
    type Point struct {
    	Latitude             int32    `protobuf:"varint,1,opt,name=latitude,proto3" json:"latitude,omitempty"`
    	Longitude            int32    `protobuf:"varint,2,opt,name=longitude,proto3" json:"longitude,omitempty"`
    	XXX_NoUnkeyedLiteral struct{} `json:"-"`
    	XXX_unrecognized     []byte   `json:"-"`
    	XXX_sizecache        int32    `json:"-"`
    }
    
    func (m *Point) Reset()         { *m = Point{} }
    func (m *Point) String() string { return proto.CompactTextString(m) }
    func (*Point) ProtoMessage()    {}
    func (*Point) Descriptor() ([]byte, []int) {
    	return fileDescriptor_b7d679f20da65b7b, []int{0}
    }
    
    func (m *Point) XXX_Unmarshal(b []byte) error {
    	return xxx_messageInfo_Point.Unmarshal(m, b)
    }
    func (m *Point) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    	return xxx_messageInfo_Point.Marshal(b, m, deterministic)
    }
    func (m *Point) XXX_Merge(src proto.Message) {
    	xxx_messageInfo_Point.Merge(m, src)
    }
    func (m *Point) XXX_Size() int {
    	return xxx_messageInfo_Point.Size(m)
    }
    func (m *Point) XXX_DiscardUnknown() {
    	xxx_messageInfo_Point.DiscardUnknown(m)
    }
    
    var xxx_messageInfo_Point proto.InternalMessageInfo
    
    func (m *Point) GetLatitude() int32 {
    	if m != nil {
    		return m.Latitude
    	}
    	return 0
    }
    
    func (m *Point) GetLongitude() int32 {
    	if m != nil {
    		return m.Longitude
    	}
    	return 0
    }
    
    // A latitude-longitude rectangle, represented as two diagonally opposite
    // points "lo" and "hi".
    type Rectangle struct {
    	// One corner of the rectangle.
    	Lo *Point `protobuf:"bytes,1,opt,name=lo,proto3" json:"lo,omitempty"`
    	// The other corner of the rectangle.
    	Hi                   *Point   `protobuf:"bytes,2,opt,name=hi,proto3" json:"hi,omitempty"`
    	XXX_NoUnkeyedLiteral struct{} `json:"-"`
    	XXX_unrecognized     []byte   `json:"-"`
    	XXX_sizecache        int32    `json:"-"`
    }
    
    func (m *Rectangle) Reset()         { *m = Rectangle{} }
    func (m *Rectangle) String() string { return proto.CompactTextString(m) }
    func (*Rectangle) ProtoMessage()    {}
    func (*Rectangle) Descriptor() ([]byte, []int) {
    	return fileDescriptor_b7d679f20da65b7b, []int{1}
    }
    
    func (m *Rectangle) XXX_Unmarshal(b []byte) error {
    	return xxx_messageInfo_Rectangle.Unmarshal(m, b)
    }
    func (m *Rectangle) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    	return xxx_messageInfo_Rectangle.Marshal(b, m, deterministic)
    }
    func (m *Rectangle) XXX_Merge(src proto.Message) {
    	xxx_messageInfo_Rectangle.Merge(m, src)
    }
    func (m *Rectangle) XXX_Size() int {
    	return xxx_messageInfo_Rectangle.Size(m)
    }
    func (m *Rectangle) XXX_DiscardUnknown() {
    	xxx_messageInfo_Rectangle.DiscardUnknown(m)
    }
    
    var xxx_messageInfo_Rectangle proto.InternalMessageInfo
    
    func (m *Rectangle) GetLo() *Point {
    	if m != nil {
    		return m.Lo
    	}
    	return nil
    }
    
    func (m *Rectangle) GetHi() *Point {
    	if m != nil {
    		return m.Hi
    	}
    	return nil
    }
    
    // A feature names something at a given point.
    //
    // If a feature could not be named, the name is empty.
    type Feature struct {
    	// The name of the feature.
    	Name string `protobuf:"bytes,1,opt,name=name,proto3" json:"name,omitempty"`
    	// The point where the feature is detected.
    	Location             *Point   `protobuf:"bytes,2,opt,name=location,proto3" json:"location,omitempty"`
    	XXX_NoUnkeyedLiteral struct{} `json:"-"`
    	XXX_unrecognized     []byte   `json:"-"`
    	XXX_sizecache        int32    `json:"-"`
    }
    
    func (m *Feature) Reset()         { *m = Feature{} }
    func (m *Feature) String() string { return proto.CompactTextString(m) }
    func (*Feature) ProtoMessage()    {}
    func (*Feature) Descriptor() ([]byte, []int) {
    	return fileDescriptor_b7d679f20da65b7b, []int{2}
    }
    
    func (m *Feature) XXX_Unmarshal(b []byte) error {
    	return xxx_messageInfo_Feature.Unmarshal(m, b)
    }
    func (m *Feature) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    	return xxx_messageInfo_Feature.Marshal(b, m, deterministic)
    }
    func (m *Feature) XXX_Merge(src proto.Message) {
    	xxx_messageInfo_Feature.Merge(m, src)
    }
    func (m *Feature) XXX_Size() int {
    	return xxx_messageInfo_Feature.Size(m)
    }
    func (m *Feature) XXX_DiscardUnknown() {
    	xxx_messageInfo_Feature.DiscardUnknown(m)
    }
    
    var xxx_messageInfo_Feature proto.InternalMessageInfo
    
    func (m *Feature) GetName() string {
    	if m != nil {
    		return m.Name
    	}
    	return ""
    }
    
    func (m *Feature) GetLocation() *Point {
    	if m != nil {
    		return m.Location
    	}
    	return nil
    }
    
    // A RouteNote is a message sent while at a given point.
    type RouteNote struct {
    	// The location from which the message is sent.
    	Location *Point `protobuf:"bytes,1,opt,name=location,proto3" json:"location,omitempty"`
    	// The message to be sent.
    	Message              string   `protobuf:"bytes,2,opt,name=message,proto3" json:"message,omitempty"`
    	XXX_NoUnkeyedLiteral struct{} `json:"-"`
    	XXX_unrecognized     []byte   `json:"-"`
    	XXX_sizecache        int32    `json:"-"`
    }
    
    func (m *RouteNote) Reset()         { *m = RouteNote{} }
    func (m *RouteNote) String() string { return proto.CompactTextString(m) }
    func (*RouteNote) ProtoMessage()    {}
    func (*RouteNote) Descriptor() ([]byte, []int) {
    	return fileDescriptor_b7d679f20da65b7b, []int{3}
    }
    
    func (m *RouteNote) XXX_Unmarshal(b []byte) error {
    	return xxx_messageInfo_RouteNote.Unmarshal(m, b)
    }
    func (m *RouteNote) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    	return xxx_messageInfo_RouteNote.Marshal(b, m, deterministic)
    }
    func (m *RouteNote) XXX_Merge(src proto.Message) {
    	xxx_messageInfo_RouteNote.Merge(m, src)
    }
    func (m *RouteNote) XXX_Size() int {
    	return xxx_messageInfo_RouteNote.Size(m)
    }
    func (m *RouteNote) XXX_DiscardUnknown() {
    	xxx_messageInfo_RouteNote.DiscardUnknown(m)
    }
    
    var xxx_messageInfo_RouteNote proto.InternalMessageInfo
    
    func (m *RouteNote) GetLocation() *Point {
    	if m != nil {
    		return m.Location
    	}
    	return nil
    }
    
    func (m *RouteNote) GetMessage() string {
    	if m != nil {
    		return m.Message
    	}
    	return ""
    }
    
    // A RouteSummary is received in response to a RecordRoute rpc.
    //
    // It contains the number of individual points received, the number of
    // detected features, and the total distance covered as the cumulative sum of
    // the distance between each point.
    type RouteSummary struct {
    	// The number of points received.
    	PointCount int32 `protobuf:"varint,1,opt,name=point_count,json=pointCount,proto3" json:"point_count,omitempty"`
    	// The number of known features passed while traversing the route.
    	FeatureCount int32 `protobuf:"varint,2,opt,name=feature_count,json=featureCount,proto3" json:"feature_count,omitempty"`
    	// The distance covered in metres.
    	Distance int32 `protobuf:"varint,3,opt,name=distance,proto3" json:"distance,omitempty"`
    	// The duration of the traversal in seconds.
    	ElapsedTime          int32    `protobuf:"varint,4,opt,name=elapsed_time,json=elapsedTime,proto3" json:"elapsed_time,omitempty"`
    	XXX_NoUnkeyedLiteral struct{} `json:"-"`
    	XXX_unrecognized     []byte   `json:"-"`
    	XXX_sizecache        int32    `json:"-"`
    }
    
    func (m *RouteSummary) Reset()         { *m = RouteSummary{} }
    func (m *RouteSummary) String() string { return proto.CompactTextString(m) }
    func (*RouteSummary) ProtoMessage()    {}
    func (*RouteSummary) Descriptor() ([]byte, []int) {
    	return fileDescriptor_b7d679f20da65b7b, []int{4}
    }
    
    func (m *RouteSummary) XXX_Unmarshal(b []byte) error {
    	return xxx_messageInfo_RouteSummary.Unmarshal(m, b)
    }
    func (m *RouteSummary) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
    	return xxx_messageInfo_RouteSummary.Marshal(b, m, deterministic)
    }
    func (m *RouteSummary) XXX_Merge(src proto.Message) {
    	xxx_messageInfo_RouteSummary.Merge(m, src)
    }
    func (m *RouteSummary) XXX_Size() int {
    	return xxx_messageInfo_RouteSummary.Size(m)
    }
    func (m *RouteSummary) XXX_DiscardUnknown() {
    	xxx_messageInfo_RouteSummary.DiscardUnknown(m)
    }
    
    var xxx_messageInfo_RouteSummary proto.InternalMessageInfo
    
    func (m *RouteSummary) GetPointCount() int32 {
    	if m != nil {
    		return m.PointCount
    	}
    	return 0
    }
    
    func (m *RouteSummary) GetFeatureCount() int32 {
    	if m != nil {
    		return m.FeatureCount
    	}
    	return 0
    }
    
    func (m *RouteSummary) GetDistance() int32 {
    	if m != nil {
    		return m.Distance
    	}
    	return 0
    }
    
    func (m *RouteSummary) GetElapsedTime() int32 {
    	if m != nil {
    		return m.ElapsedTime
    	}
    	return 0
    }
    
    func init() {
    	proto.RegisterType((*Point)(nil), "routeguide.Point")
    	proto.RegisterType((*Rectangle)(nil), "routeguide.Rectangle")
    	proto.RegisterType((*Feature)(nil), "routeguide.Feature")
    	proto.RegisterType((*RouteNote)(nil), "routeguide.RouteNote")
    	proto.RegisterType((*RouteSummary)(nil), "routeguide.RouteSummary")
    }
    
    func init() { proto.RegisterFile("route_guide.proto", fileDescriptor_b7d679f20da65b7b) }
    
    var fileDescriptor_b7d679f20da65b7b = []byte{
    	// 414 bytes of a gzipped FileDescriptorProto
    	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x84, 0x53, 0xdd, 0x8a, 0xd3, 0x40,
    	0x14, 0xde, 0xc9, 0xee, 0xba, 0xcd, 0x49, 0x44, 0xf6, 0x88, 0x10, 0xa2, 0xa0, 0x1b, 0x6f, 0xf6,
    	0xc6, 0xb0, 0xac, 0xb0, 0x97, 0x15, 0x5b, 0xb0, 0x37, 0x45, 0xea, 0xd8, 0xfb, 0x32, 0x26, 0xc7,
    	0x74, 0x60, 0x92, 0x09, 0xc9, 0x04, 0xf4, 0x01, 0x7c, 0x02, 0xdf, 0xc0, 0x27, 0x95, 0x4c, 0x92,
    	0x36, 0xd5, 0x96, 0xbd, 0x9b, 0xf3, 0x9d, 0xef, 0x3b, 0x3f, 0xdf, 0x61, 0xe0, 0xba, 0xd2, 0x8d,
    	0xa1, 0x4d, 0xd6, 0xc8, 0x94, 0xe2, 0xb2, 0xd2, 0x46, 0x23, 0x58, 0xc8, 0x22, 0xd1, 0x47, 0xb8,
    	0x5c, 0x69, 0x59, 0x18, 0x0c, 0x61, 0xa2, 0x84, 0x91, 0xa6, 0x49, 0x29, 0x60, 0x6f, 0xd8, 0xed,
    	0x25, 0xdf, 0xc5, 0xf8, 0x0a, 0x5c, 0xa5, 0x8b, 0xac, 0x4b, 0x3a, 0x36, 0xb9, 0x07, 0xa2, 0x2f,
    	0xe0, 0x72, 0x4a, 0x8c, 0x28, 0x32, 0x45, 0x78, 0x03, 0x8e, 0xd2, 0xb6, 0x80, 0x77, 0x7f, 0x1d,
    	0xef, 0x1b, 0xc5, 0xb6, 0x0b, 0x77, 0x94, 0x6e, 0x29, 0x5b, 0x69, 0xcb, 0x1c, 0xa7, 0x6c, 0x65,
    	0xb4, 0x84, 0xab, 0x4f, 0x24, 0x4c, 0x53, 0x11, 0x22, 0x5c, 0x14, 0x22, 0xef, 0x66, 0x72, 0xb9,
    	0x7d, 0xe3, 0x3b, 0x98, 0x28, 0x9d, 0x08, 0x23, 0x75, 0x71, 0xba, 0xce, 0x8e, 0x12, 0xad, 0xc1,
    	0xe5, 0x6d, 0xf6, 0xb3, 0x36, 0x87, 0x5a, 0xf6, 0xa8, 0x16, 0x03, 0xb8, 0xca, 0xa9, 0xae, 0x45,
    	0xd6, 0x2d, 0xee, 0xf2, 0x21, 0x8c, 0x7e, 0x33, 0xf0, 0x6d, 0xd9, 0xaf, 0x4d, 0x9e, 0x8b, 0xea,
    	0x27, 0xbe, 0x06, 0xaf, 0x6c, 0xd5, 0x9b, 0x44, 0x37, 0x85, 0xe9, 0x4d, 0x04, 0x0b, 0xcd, 0x5b,
    	0x04, 0xdf, 0xc2, 0xd3, 0xef, 0xdd, 0x56, 0x3d, 0xa5, 0xb3, 0xd2, 0xef, 0xc1, 0x8e, 0x14, 0xc2,
    	0x24, 0x95, 0xb5, 0x11, 0x45, 0x42, 0xc1, 0x79, 0x77, 0x87, 0x21, 0xc6, 0x1b, 0xf0, 0x49, 0x89,
    	0xb2, 0xa6, 0x74, 0x63, 0x64, 0x4e, 0xc1, 0x85, 0xcd, 0x7b, 0x3d, 0xb6, 0x96, 0x39, 0xdd, 0xff,
    	0x72, 0x00, 0xec, 0x54, 0x8b, 0x76, 0x1d, 0x7c, 0x00, 0x58, 0x90, 0x19, 0xbc, 0xfc, 0x7f, 0xd3,
    	0xf0, 0xf9, 0x18, 0xea, 0x79, 0xd1, 0x19, 0x4e, 0xc1, 0x5f, 0xca, 0x7a, 0x10, 0xd6, 0xf8, 0x62,
    	0x4c, 0xdb, 0x5d, 0xfb, 0x84, 0xfa, 0x8e, 0xe1, 0x14, 0x3c, 0x4e, 0x89, 0xae, 0x52, 0x3b, 0xcb,
    	0xb1, 0xc6, 0xc1, 0x41, 0xc5, 0x91, 0x8f, 0xd1, 0xd9, 0x2d, 0xc3, 0x0f, 0xfd, 0xc9, 0xe6, 0x5b,
    	0x61, 0xfe, 0x69, 0x3e, 0x5c, 0x32, 0x3c, 0x0e, 0xb7, 0xf2, 0x3b, 0x36, 0x7b, 0x80, 0x97, 0x52,
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    	0xad, 0xda, 0x3f, 0xb1, 0x62, 0x7f, 0x9c, 0x73, 0xbe, 0x5e, 0x7c, 0x7b, 0x62, 0xbf, 0xc8, 0xfb,
    	0xbf, 0x01, 0x00, 0x00, 0xff, 0xff, 0xf3, 0xe2, 0x76, 0x5e, 0x37, 0x03, 0x00, 0x00,
    }
    
    

    サーバの作成
    package main
    
    import (
    	"context"
    	"encoding/json"
    	"flag"
    	"fmt"
    	"io"
    	"io/ioutil"
    	"log"
    	"math"
    	"net"
    	"sync"
    	"time"
    
    	"google.golang.org/grpc"
    
    	"google.golang.org/grpc/credentials"
    	"google.golang.org/grpc/testdata"
    
    	"github.com/golang/protobuf/proto"
    
    	pb "google.golang.org/grpc/examples/route_guide/routeguide"
    )
    
    var (
    	tls        = flag.Bool("tls", false, "Connection uses TLS if true, else plain TCP")
    	certFile   = flag.String("cert_file", "", "The TLS cert file")
    	keyFile    = flag.String("key_file", "", "The TLS key file")
    	jsonDBFile = flag.String("json_db_file", "", "A json file containing a list of features")
    	port       = flag.Int("port", 10000, "The server port")
    )
    
    type routeGuideServer struct {
    	savedFeatures []*pb.Feature // read-only after initialized
    
    	mu         sync.Mutex // protects routeNotes
    	routeNotes map[string][]*pb.RouteNote
    }
    
    // GetFeature returns the feature at the given point.
    func (s *routeGuideServer) GetFeature(ctx context.Context, point *pb.Point) (*pb.Feature, error) {
    	for _, feature := range s.savedFeatures {
    		if proto.Equal(feature.Location, point) {
    			return feature, nil
    		}
    	}
    	// No feature was found, return an unnamed feature
    	return &pb.Feature{Location: point}, nil
    }
    
    // ListFeatures lists all features contained within the given bounding Rectangle.
    func (s *routeGuideServer) ListFeatures(rect *pb.Rectangle, stream pb.RouteGuide_ListFeaturesServer) error {
    	for _, feature := range s.savedFeatures {
    		if inRange(feature.Location, rect) {
    			if err := stream.Send(feature); err != nil {
    				return err
    			}
    		}
    	}
    	return nil
    }
    
    // RecordRoute records a route composited of a sequence of points.
    //
    // It gets a stream of points, and responds with statistics about the "trip":
    // number of points,  number of known features visited, total distance traveled, and
    // total time spent.
    func (s *routeGuideServer) RecordRoute(stream pb.RouteGuide_RecordRouteServer) error {
    	var pointCount, featureCount, distance int32
    	var lastPoint *pb.Point
    	startTime := time.Now()
    	for {
    		point, err := stream.Recv()
    		if err == io.EOF {
    			endTime := time.Now()
    			return stream.SendAndClose(&pb.RouteSummary{
    				PointCount:   pointCount,
    				FeatureCount: featureCount,
    				Distance:     distance,
    				ElapsedTime:  int32(endTime.Sub(startTime).Seconds()),
    			})
    		}
    		if err != nil {
    			return err
    		}
    		pointCount++
    		for _, feature := range s.savedFeatures {
    			if proto.Equal(feature.Location, point) {
    				featureCount++
    			}
    		}
    		if lastPoint != nil {
    			distance += calcDistance(lastPoint, point)
    		}
    		lastPoint = point
    	}
    }
    
    // RouteChat receives a stream of message/location pairs, and responds with a stream of all
    // previous messages at each of those locations.
    func (s *routeGuideServer) RouteChat(stream pb.RouteGuide_RouteChatServer) error {
    	for {
    		in, err := stream.Recv()
    		if err == io.EOF {
    			return nil
    		}
    		if err != nil {
    			return err
    		}
    		key := serialize(in.Location)
    
    		s.mu.Lock()
    		s.routeNotes[key] = append(s.routeNotes[key], in)
    		// Note: this copy prevents blocking other clients while serving this one.
    		// We don't need to do a deep copy, because elements in the slice are
    		// insert-only and never modified.
    		rn := make([]*pb.RouteNote, len(s.routeNotes[key]))
    		copy(rn, s.routeNotes[key])
    		s.mu.Unlock()
    
    		for _, note := range rn {
    			if err := stream.Send(note); err != nil {
    				return err
    			}
    		}
    	}
    }
    
    // loadFeatures loads features from a JSON file.
    func (s *routeGuideServer) loadFeatures(filePath string) {
    	var data []byte
    	if filePath != "" {
    		var err error
    		data, err = ioutil.ReadFile(filePath)
    		if err != nil {
    			log.Fatalf("Failed to load default features: %v", err)
    		}
    	} else {
    		data = exampleData
    	}
    	if err := json.Unmarshal(data, &s.savedFeatures); err != nil {
    		log.Fatalf("Failed to load default features: %v", err)
    	}
    }
    
    func toRadians(num float64) float64 {
    	return num * math.Pi / float64(180)
    }
    
    // calcDistance calculates the distance between two points using the "haversine" formula.
    // The formula is based on http://mathforum.org/library/drmath/view/51879.html.
    func calcDistance(p1 *pb.Point, p2 *pb.Point) int32 {
    	const CordFactor float64 = 1e7
    	const R = float64(6371000) // earth radius in metres
    	lat1 := toRadians(float64(p1.Latitude) / CordFactor)
    	lat2 := toRadians(float64(p2.Latitude) / CordFactor)
    	lng1 := toRadians(float64(p1.Longitude) / CordFactor)
    	lng2 := toRadians(float64(p2.Longitude) / CordFactor)
    	dlat := lat2 - lat1
    	dlng := lng2 - lng1
    
    	a := math.Sin(dlat/2)*math.Sin(dlat/2) +
    		math.Cos(lat1)*math.Cos(lat2)*
    			math.Sin(dlng/2)*math.Sin(dlng/2)
    	c := 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a))
    
    	distance := R * c
    	return int32(distance)
    }
    
    func inRange(point *pb.Point, rect *pb.Rectangle) bool {
    	left := math.Min(float64(rect.Lo.Longitude), float64(rect.Hi.Longitude))
    	right := math.Max(float64(rect.Lo.Longitude), float64(rect.Hi.Longitude))
    	top := math.Max(float64(rect.Lo.Latitude), float64(rect.Hi.Latitude))
    	bottom := math.Min(float64(rect.Lo.Latitude), float64(rect.Hi.Latitude))
    
    	if float64(point.Longitude) >= left &&
    		float64(point.Longitude) <= right &&
    		float64(point.Latitude) >= bottom &&
    		float64(point.Latitude) <= top {
    		return true
    	}
    	return false
    }
    
    func serialize(point *pb.Point) string {
    	return fmt.Sprintf("%d %d", point.Latitude, point.Longitude)
    }
    
    func newServer() *routeGuideServer {
    	s := &routeGuideServer{routeNotes: make(map[string][]*pb.RouteNote)}
    	s.loadFeatures(*jsonDBFile)
    	return s
    }
    
    func main() {
    	flag.Parse()
    	lis, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", *port))
    	if err != nil {
    		log.Fatalf("failed to listen: %v", err)
    	}
    	var opts []grpc.ServerOption
    	if *tls {
    		if *certFile == "" {
    			*certFile = testdata.Path("server1.pem")
    		}
    		if *keyFile == "" {
    			*keyFile = testdata.Path("server1.key")
    		}
    		creds, err := credentials.NewServerTLSFromFile(*certFile, *keyFile)
    		if err != nil {
    			log.Fatalf("Failed to generate credentials %v", err)
    		}
    		opts = []grpc.ServerOption{grpc.Creds(creds)}
    	}
    	grpcServer := grpc.NewServer(opts...)
    	pb.RegisterRouteGuideServer(grpcServer, newServer())
    	grpcServer.Serve(lis)
    }
    
    // exampleData is a copy of testdata/route_guide_db.json. It's to avoid
    // specifying file path with `go run`.
    var exampleData = []byte(`[{
        "location": {
            "latitude": 407838351,
            "longitude": -746143763
        },
        "name": "Patriots Path, Mendham, NJ 07945, USA"
    }, {
        "location": {
            "latitude": 408122808,
            "longitude": -743999179
        },
        "name": "101 New Jersey 10, Whippany, NJ 07981, USA"
    }, {
        "location": {
            "latitude": 413628156,
            "longitude": -749015468
        },
        "name": "U.S. 6, Shohola, PA 18458, USA"
    }, {
        "location": {
            "latitude": 419999544,
            "longitude": -740371136
        },
        "name": "5 Conners Road, Kingston, NY 12401, USA"
    }, {
        "location": {
            "latitude": 414008389,
            "longitude": -743951297
        },
        "name": "Mid Hudson Psychiatric Center, New Hampton, NY 10958, USA"
    }, {
        "location": {
            "latitude": 419611318,
            "longitude": -746524769
        },
        "name": "287 Flugertown Road, Livingston Manor, NY 12758, USA"
    }, {
        "location": {
            "latitude": 406109563,
            "longitude": -742186778
        },
        "name": "4001 Tremley Point Road, Linden, NJ 07036, USA"
    }, {
        "location": {
            "latitude": 416802456,
            "longitude": -742370183
        },
        "name": "352 South Mountain Road, Wallkill, NY 12589, USA"
    }, {
        "location": {
            "latitude": 412950425,
            "longitude": -741077389
        },
        "name": "Bailey Turn Road, Harriman, NY 10926, USA"
    }, {
        "location": {
            "latitude": 412144655,
            "longitude": -743949739
        },
        "name": "193-199 Wawayanda Road, Hewitt, NJ 07421, USA"
    }, {
        "location": {
            "latitude": 415736605,
            "longitude": -742847522
        },
        "name": "406-496 Ward Avenue, Pine Bush, NY 12566, USA"
    }, {
        "location": {
            "latitude": 413843930,
            "longitude": -740501726
        },
        "name": "162 Merrill Road, Highland Mills, NY 10930, USA"
    }, {
        "location": {
            "latitude": 410873075,
            "longitude": -744459023
        },
        "name": "Clinton Road, West Milford, NJ 07480, USA"
    }, {
        "location": {
            "latitude": 412346009,
            "longitude": -744026814
        },
        "name": "16 Old Brook Lane, Warwick, NY 10990, USA"
    }, {
        "location": {
            "latitude": 402948455,
            "longitude": -747903913
        },
        "name": "3 Drake Lane, Pennington, NJ 08534, USA"
    }, {
        "location": {
            "latitude": 406337092,
            "longitude": -740122226
        },
        "name": "6324 8th Avenue, Brooklyn, NY 11220, USA"
    }, {
        "location": {
            "latitude": 406421967,
            "longitude": -747727624
        },
        "name": "1 Merck Access Road, Whitehouse Station, NJ 08889, USA"
    }, {
        "location": {
            "latitude": 416318082,
            "longitude": -749677716
        },
        "name": "78-98 Schalck Road, Narrowsburg, NY 12764, USA"
    }, {
        "location": {
            "latitude": 415301720,
            "longitude": -748416257
        },
        "name": "282 Lakeview Drive Road, Highland Lake, NY 12743, USA"
    }, {
        "location": {
            "latitude": 402647019,
            "longitude": -747071791
        },
        "name": "330 Evelyn Avenue, Hamilton Township, NJ 08619, USA"
    }, {
        "location": {
            "latitude": 412567807,
            "longitude": -741058078
        },
        "name": "New York State Reference Route 987E, Southfields, NY 10975, USA"
    }, {
        "location": {
            "latitude": 416855156,
            "longitude": -744420597
        },
        "name": "103-271 Tempaloni Road, Ellenville, NY 12428, USA"
    }, {
        "location": {
            "latitude": 404663628,
            "longitude": -744820157
        },
        "name": "1300 Airport Road, North Brunswick Township, NJ 08902, USA"
    }, {
        "location": {
            "latitude": 407113723,
            "longitude": -749746483
        },
        "name": ""
    }, {
        "location": {
            "latitude": 402133926,
            "longitude": -743613249
        },
        "name": ""
    }, {
        "location": {
            "latitude": 400273442,
            "longitude": -741220915
        },
        "name": ""
    }, {
        "location": {
            "latitude": 411236786,
            "longitude": -744070769
        },
        "name": ""
    }, {
        "location": {
            "latitude": 411633782,
            "longitude": -746784970
        },
        "name": "211-225 Plains Road, Augusta, NJ 07822, USA"
    }, {
        "location": {
            "latitude": 415830701,
            "longitude": -742952812
        },
        "name": ""
    }, {
        "location": {
            "latitude": 413447164,
            "longitude": -748712898
        },
        "name": "165 Pedersen Ridge Road, Milford, PA 18337, USA"
    }, {
        "location": {
            "latitude": 405047245,
            "longitude": -749800722
        },
        "name": "100-122 Locktown Road, Frenchtown, NJ 08825, USA"
    }, {
        "location": {
            "latitude": 418858923,
            "longitude": -746156790
        },
        "name": ""
    }, {
        "location": {
            "latitude": 417951888,
            "longitude": -748484944
        },
        "name": "650-652 Willi Hill Road, Swan Lake, NY 12783, USA"
    }, {
        "location": {
            "latitude": 407033786,
            "longitude": -743977337
        },
        "name": "26 East 3rd Street, New Providence, NJ 07974, USA"
    }, {
        "location": {
            "latitude": 417548014,
            "longitude": -740075041
        },
        "name": ""
    }, {
        "location": {
            "latitude": 410395868,
            "longitude": -744972325
        },
        "name": ""
    }, {
        "location": {
            "latitude": 404615353,
            "longitude": -745129803
        },
        "name": ""
    }, {
        "location": {
            "latitude": 406589790,
            "longitude": -743560121
        },
        "name": "611 Lawrence Avenue, Westfield, NJ 07090, USA"
    }, {
        "location": {
            "latitude": 414653148,
            "longitude": -740477477
        },
        "name": "18 Lannis Avenue, New Windsor, NY 12553, USA"
    }, {
        "location": {
            "latitude": 405957808,
            "longitude": -743255336
        },
        "name": "82-104 Amherst Avenue, Colonia, NJ 07067, USA"
    }, {
        "location": {
            "latitude": 411733589,
            "longitude": -741648093
        },
        "name": "170 Seven Lakes Drive, Sloatsburg, NY 10974, USA"
    }, {
        "location": {
            "latitude": 412676291,
            "longitude": -742606606
        },
        "name": "1270 Lakes Road, Monroe, NY 10950, USA"
    }, {
        "location": {
            "latitude": 409224445,
            "longitude": -748286738
        },
        "name": "509-535 Alphano Road, Great Meadows, NJ 07838, USA"
    }, {
        "location": {
            "latitude": 406523420,
            "longitude": -742135517
        },
        "name": "652 Garden Street, Elizabeth, NJ 07202, USA"
    }, {
        "location": {
            "latitude": 401827388,
            "longitude": -740294537
        },
        "name": "349 Sea Spray Court, Neptune City, NJ 07753, USA"
    }, {
        "location": {
            "latitude": 410564152,
            "longitude": -743685054
        },
        "name": "13-17 Stanley Street, West Milford, NJ 07480, USA"
    }, {
        "location": {
            "latitude": 408472324,
            "longitude": -740726046
        },
        "name": "47 Industrial Avenue, Teterboro, NJ 07608, USA"
    }, {
        "location": {
            "latitude": 412452168,
            "longitude": -740214052
        },
        "name": "5 White Oak Lane, Stony Point, NY 10980, USA"
    }, {
        "location": {
            "latitude": 409146138,
            "longitude": -746188906
        },
        "name": "Berkshire Valley Management Area Trail, Jefferson, NJ, USA"
    }, {
        "location": {
            "latitude": 404701380,
            "longitude": -744781745
        },
        "name": "1007 Jersey Avenue, New Brunswick, NJ 08901, USA"
    }, {
        "location": {
            "latitude": 409642566,
            "longitude": -746017679
        },
        "name": "6 East Emerald Isle Drive, Lake Hopatcong, NJ 07849, USA"
    }, {
        "location": {
            "latitude": 408031728,
            "longitude": -748645385
        },
        "name": "1358-1474 New Jersey 57, Port Murray, NJ 07865, USA"
    }, {
        "location": {
            "latitude": 413700272,
            "longitude": -742135189
        },
        "name": "367 Prospect Road, Chester, NY 10918, USA"
    }, {
        "location": {
            "latitude": 404310607,
            "longitude": -740282632
        },
        "name": "10 Simon Lake Drive, Atlantic Highlands, NJ 07716, USA"
    }, {
        "location": {
            "latitude": 409319800,
            "longitude": -746201391
        },
        "name": "11 Ward Street, Mount Arlington, NJ 07856, USA"
    }, {
        "location": {
            "latitude": 406685311,
            "longitude": -742108603
        },
        "name": "300-398 Jefferson Avenue, Elizabeth, NJ 07201, USA"
    }, {
        "location": {
            "latitude": 419018117,
            "longitude": -749142781
        },
        "name": "43 Dreher Road, Roscoe, NY 12776, USA"
    }, {
        "location": {
            "latitude": 412856162,
            "longitude": -745148837
        },
        "name": "Swan Street, Pine Island, NY 10969, USA"
    }, {
        "location": {
            "latitude": 416560744,
            "longitude": -746721964
        },
        "name": "66 Pleasantview Avenue, Monticello, NY 12701, USA"
    }, {
        "location": {
            "latitude": 405314270,
            "longitude": -749836354
        },
        "name": ""
    }, {
        "location": {
            "latitude": 414219548,
            "longitude": -743327440
        },
        "name": ""
    }, {
        "location": {
            "latitude": 415534177,
            "longitude": -742900616
        },
        "name": "565 Winding Hills Road, Montgomery, NY 12549, USA"
    }, {
        "location": {
            "latitude": 406898530,
            "longitude": -749127080
        },
        "name": "231 Rocky Run Road, Glen Gardner, NJ 08826, USA"
    }, {
        "location": {
            "latitude": 407586880,
            "longitude": -741670168
        },
        "name": "100 Mount Pleasant Avenue, Newark, NJ 07104, USA"
    }, {
        "location": {
            "latitude": 400106455,
            "longitude": -742870190
        },
        "name": "517-521 Huntington Drive, Manchester Township, NJ 08759, USA"
    }, {
        "location": {
            "latitude": 400066188,
            "longitude": -746793294
        },
        "name": ""
    }, {
        "location": {
            "latitude": 418803880,
            "longitude": -744102673
        },
        "name": "40 Mountain Road, Napanoch, NY 12458, USA"
    }, {
        "location": {
            "latitude": 414204288,
            "longitude": -747895140
        },
        "name": ""
    }, {
        "location": {
            "latitude": 414777405,
            "longitude": -740615601
        },
        "name": ""
    }, {
        "location": {
            "latitude": 415464475,
            "longitude": -747175374
        },
        "name": "48 North Road, Forestburgh, NY 12777, USA"
    }, {
        "location": {
            "latitude": 404062378,
            "longitude": -746376177
        },
        "name": ""
    }, {
        "location": {
            "latitude": 405688272,
            "longitude": -749285130
        },
        "name": ""
    }, {
        "location": {
            "latitude": 400342070,
            "longitude": -748788996
        },
        "name": ""
    }, {
        "location": {
            "latitude": 401809022,
            "longitude": -744157964
        },
        "name": ""
    }, {
        "location": {
            "latitude": 404226644,
            "longitude": -740517141
        },
        "name": "9 Thompson Avenue, Leonardo, NJ 07737, USA"
    }, {
        "location": {
            "latitude": 410322033,
            "longitude": -747871659
        },
        "name": ""
    }, {
        "location": {
            "latitude": 407100674,
            "longitude": -747742727
        },
        "name": ""
    }, {
        "location": {
            "latitude": 418811433,
            "longitude": -741718005
        },
        "name": "213 Bush Road, Stone Ridge, NY 12484, USA"
    }, {
        "location": {
            "latitude": 415034302,
            "longitude": -743850945
        },
        "name": ""
    }, {
        "location": {
            "latitude": 411349992,
            "longitude": -743694161
        },
        "name": ""
    }, {
        "location": {
            "latitude": 404839914,
            "longitude": -744759616
        },
        "name": "1-17 Bergen Court, New Brunswick, NJ 08901, USA"
    }, {
        "location": {
            "latitude": 414638017,
            "longitude": -745957854
        },
        "name": "35 Oakland Valley Road, Cuddebackville, NY 12729, USA"
    }, {
        "location": {
            "latitude": 412127800,
            "longitude": -740173578
        },
        "name": ""
    }, {
        "location": {
            "latitude": 401263460,
            "longitude": -747964303
        },
        "name": ""
    }, {
        "location": {
            "latitude": 412843391,
            "longitude": -749086026
        },
        "name": ""
    }, {
        "location": {
            "latitude": 418512773,
            "longitude": -743067823
        },
        "name": ""
    }, {
        "location": {
            "latitude": 404318328,
            "longitude": -740835638
        },
        "name": "42-102 Main Street, Belford, NJ 07718, USA"
    }, {
        "location": {
            "latitude": 419020746,
            "longitude": -741172328
        },
        "name": ""
    }, {
        "location": {
            "latitude": 404080723,
            "longitude": -746119569
        },
        "name": ""
    }, {
        "location": {
            "latitude": 401012643,
            "longitude": -744035134
        },
        "name": ""
    }, {
        "location": {
            "latitude": 404306372,
            "longitude": -741079661
        },
        "name": ""
    }, {
        "location": {
            "latitude": 403966326,
            "longitude": -748519297
        },
        "name": ""
    }, {
        "location": {
            "latitude": 405002031,
            "longitude": -748407866
        },
        "name": ""
    }, {
        "location": {
            "latitude": 409532885,
            "longitude": -742200683
        },
        "name": ""
    }, {
        "location": {
            "latitude": 416851321,
            "longitude": -742674555
        },
        "name": ""
    }, {
        "location": {
            "latitude": 406411633,
            "longitude": -741722051
        },
        "name": "3387 Richmond Terrace, Staten Island, NY 10303, USA"
    }, {
        "location": {
            "latitude": 413069058,
            "longitude": -744597778
        },
        "name": "261 Van Sickle Road, Goshen, NY 10924, USA"
    }, {
        "location": {
            "latitude": 418465462,
            "longitude": -746859398
        },
        "name": ""
    }, {
        "location": {
            "latitude": 411733222,
            "longitude": -744228360
        },
        "name": ""
    }, {
        "location": {
            "latitude": 410248224,
            "longitude": -747127767
        },
        "name": "3 Hasta Way, Newton, NJ 07860, USA"
    }]`)
    

    クライアントの作成
    package main
    
    import (
    	"context"
    	"flag"
    	"io"
    	"log"
    	"math/rand"
    	"time"
    
    	"google.golang.org/grpc"
    	"google.golang.org/grpc/credentials"
    	pb "google.golang.org/grpc/examples/route_guide/routeguide"
    	"google.golang.org/grpc/testdata"
    )
    
    var (
    	tls                = flag.Bool("tls", false, "Connection uses TLS if true, else plain TCP")
    	caFile             = flag.String("ca_file", "", "The file containing the CA root cert file")
    	serverAddr         = flag.String("server_addr", "127.0.0.1:10000", "The server address in the format of host:port")
    	serverHostOverride = flag.String("server_host_override", "x.test.youtube.com", "The server name use to verify the hostname returned by TLS handshake")
    )
    
    // printFeature gets the feature for the given point.
    func printFeature(client pb.RouteGuideClient, point *pb.Point) {
    	log.Printf("Getting feature for point (%d, %d)", point.Latitude, point.Longitude)
    	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    	defer cancel()
    	feature, err := client.GetFeature(ctx, point)
    	if err != nil {
    		log.Fatalf("%v.GetFeatures(_) = _, %v: ", client, err)
    	}
    	log.Println(feature)
    }
    
    // printFeatures lists all the features within the given bounding Rectangle.
    func printFeatures(client pb.RouteGuideClient, rect *pb.Rectangle) {
    	log.Printf("Looking for features within %v", rect)
    	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    	defer cancel()
    	stream, err := client.ListFeatures(ctx, rect)
    	if err != nil {
    		log.Fatalf("%v.ListFeatures(_) = _, %v", client, err)
    	}
    	for {
    		feature, err := stream.Recv()
    		if err == io.EOF {
    			break
    		}
    		if err != nil {
    			log.Fatalf("%v.ListFeatures(_) = _, %v", client, err)
    		}
    		log.Println(feature)
    	}
    }
    
    // runRecordRoute sends a sequence of points to server and expects to get a RouteSummary from server.
    func runRecordRoute(client pb.RouteGuideClient) {
    	// Create a random number of random points
    	r := rand.New(rand.NewSource(time.Now().UnixNano()))
    	pointCount := int(r.Int31n(100)) + 2 // Traverse at least two points
    	var points []*pb.Point
    	for i := 0; i < pointCount; i++ {
    		points = append(points, randomPoint(r))
    	}
    	log.Printf("Traversing %d points.", len(points))
    	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    	defer cancel()
    	stream, err := client.RecordRoute(ctx)
    	if err != nil {
    		log.Fatalf("%v.RecordRoute(_) = _, %v", client, err)
    	}
    	for _, point := range points {
    		if err := stream.Send(point); err != nil {
    			log.Fatalf("%v.Send(%v) = %v", stream, point, err)
    		}
    	}
    	reply, err := stream.CloseAndRecv()
    	if err != nil {
    		log.Fatalf("%v.CloseAndRecv() got error %v, want %v", stream, err, nil)
    	}
    	log.Printf("Route summary: %v", reply)
    }
    
    // runRouteChat receives a sequence of route notes, while sending notes for various locations.
    func runRouteChat(client pb.RouteGuideClient) {
    	notes := []*pb.RouteNote{
    		{Location: &pb.Point{Latitude: 0, Longitude: 1}, Message: "First message"},
    		{Location: &pb.Point{Latitude: 0, Longitude: 2}, Message: "Second message"},
    		{Location: &pb.Point{Latitude: 0, Longitude: 3}, Message: "Third message"},
    		{Location: &pb.Point{Latitude: 0, Longitude: 1}, Message: "Fourth message"},
    		{Location: &pb.Point{Latitude: 0, Longitude: 2}, Message: "Fifth message"},
    		{Location: &pb.Point{Latitude: 0, Longitude: 3}, Message: "Sixth message"},
    	}
    	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    	defer cancel()
    	stream, err := client.RouteChat(ctx)
    	if err != nil {
    		log.Fatalf("%v.RouteChat(_) = _, %v", client, err)
    	}
    	waitc := make(chan struct{})
    	go func() {
    		for {
    			in, err := stream.Recv()
    			if err == io.EOF {
    				// read done.
    				close(waitc)
    				return
    			}
    			if err != nil {
    				log.Fatalf("Failed to receive a note : %v", err)
    			}
    			log.Printf("Got message %s at point(%d, %d)", in.Message, in.Location.Latitude, in.Location.Longitude)
    		}
    	}()
    	for _, note := range notes {
    		if err := stream.Send(note); err != nil {
    			log.Fatalf("Failed to send a note: %v", err)
    		}
    	}
    	stream.CloseSend()