Add python async example for hellostreamingworld using generator (#27343)

* Add python async example for hellostreamingworld using generator

* add stub.read() client example + fix Copyrights + small improvements

* Format and lint + remove exernal generator

* Apply lint and auto-format

examples/python/hellostreamingworld/async_greeter_client.py

@@ -0,0 +1,47 @@
+# Copyright 2021 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""The Python AsyncIO implementation of the GRPC hellostreamingworld.MultiGreeter client."""
+
+import asyncio
+import logging
+
+import grpc
+import hellostreamingworld_pb2
+import hellostreamingworld_pb2_grpc
+
+
+async def run() -> None:
+    async with grpc.aio.insecure_channel("localhost:50051") as channel:
+        stub = hellostreamingworld_pb2_grpc.MultiGreeterStub(channel)
+
+        # Read from an async generator
+        async for response in stub.sayHello(
+            hellostreamingworld_pb2.HelloRequest(name="you")):
+            print("Greeter client received from async generator: " +
+                  response.message)
+
+        # Direct read from the stub
+        hello_stream = stub.sayHello(
+            hellostreamingworld_pb2.HelloRequest(name="you"))
+        while True:
+            response = await hello_stream.read()
+            if response == grpc.aio.EOF:
+                break
+            print("Greeter client received from direct read: " +
+                  response.message)
+
+
+if __name__ == "__main__":
+    logging.basicConfig()
+    asyncio.run(run())

examples/python/hellostreamingworld/async_greeter_server.py

@@ -0,0 +1,49 @@
+# Copyright 2021 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""The Python AsyncIO implementation of the GRPC hellostreamingworld.MultiGreeter server."""
+
+import asyncio
+import logging
+
+import grpc
+from hellostreamingworld_pb2 import HelloReply
+from hellostreamingworld_pb2 import HelloRequest
+from hellostreamingworld_pb2_grpc import MultiGreeterServicer
+from hellostreamingworld_pb2_grpc import add_MultiGreeterServicer_to_server
+
+NUMBER_OF_REPLY = 10
+
+
+class Greeter(MultiGreeterServicer):
+
+    async def sayHello(self, request: HelloRequest,
+                       context: grpc.aio.ServicerContext) -> HelloReply:
+        logging.info("Serving sayHello request %s", request)
+        for i in range(NUMBER_OF_REPLY):
+            yield HelloReply(message=f"Hello number {i}, {request.name}!")
+
+
+async def serve() -> None:
+    server = grpc.aio.server()
+    add_MultiGreeterServicer_to_server(Greeter(), server)
+    listen_addr = "[::]:50051"
+    server.add_insecure_port(listen_addr)
+    logging.info("Starting server on %s", listen_addr)
+    await server.start()
+    await server.wait_for_termination()
+
+
+if __name__ == "__main__":
+    logging.basicConfig(level=logging.INFO)
+    asyncio.run(serve())

examples/python/hellostreamingworld/hellostreamingworld_pb2.py

@@ -0,0 +1,143 @@
+# -*- coding: utf-8 -*-
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: hellostreamingworld.proto
+"""Generated protocol buffer code."""
+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
+# @@protoc_insertion_point(imports)
+
+_sym_db = _symbol_database.Default()
+
+
+
+
+DESCRIPTOR = _descriptor.FileDescriptor(
+  name='hellostreamingworld.proto',
+  package='hellostreamingworld',
+  syntax='proto3',
+  serialized_options=None,
+  create_key=_descriptor._internal_create_key,
+  serialized_pb=b'\n\x19hellostreamingworld.proto\x12\x13hellostreamingworld\"3\n\x0cHelloRequest\x12\x0c\n\x04name\x18\x01 \x01(\t\x12\x15\n\rnum_greetings\x18\x02 \x01(\t\"\x1d\n\nHelloReply\x12\x0f\n\x07message\x18\x01 \x01(\t2b\n\x0cMultiGreeter\x12R\n\x08sayHello\x12!.hellostreamingworld.HelloRequest\x1a\x1f.hellostreamingworld.HelloReply\"\x00\x30\x01\x62\x06proto3'
+)
+
+
+
+
+_HELLOREQUEST = _descriptor.Descriptor(
+  name='HelloRequest',
+  full_name='hellostreamingworld.HelloRequest',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  create_key=_descriptor._internal_create_key,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='name', full_name='hellostreamingworld.HelloRequest.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,
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+    _descriptor.FieldDescriptor(
+      name='num_greetings', full_name='hellostreamingworld.HelloRequest.num_greetings', 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,
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  serialized_options=None,
+  is_extendable=False,
+  syntax='proto3',
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=50,
+  serialized_end=101,
+)
+
+
+_HELLOREPLY = _descriptor.Descriptor(
+  name='HelloReply',
+  full_name='hellostreamingworld.HelloReply',
+  filename=None,
+  file=DESCRIPTOR,
+  containing_type=None,
+  create_key=_descriptor._internal_create_key,
+  fields=[
+    _descriptor.FieldDescriptor(
+      name='message', full_name='hellostreamingworld.HelloReply.message', 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,
+      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+  ],
+  extensions=[
+  ],
+  nested_types=[],
+  enum_types=[
+  ],
+  serialized_options=None,
+  is_extendable=False,
+  syntax='proto3',
+  extension_ranges=[],
+  oneofs=[
+  ],
+  serialized_start=103,
+  serialized_end=132,
+)
+
+DESCRIPTOR.message_types_by_name['HelloRequest'] = _HELLOREQUEST
+DESCRIPTOR.message_types_by_name['HelloReply'] = _HELLOREPLY
+_sym_db.RegisterFileDescriptor(DESCRIPTOR)
+
+HelloRequest = _reflection.GeneratedProtocolMessageType('HelloRequest', (_message.Message,), {
+  'DESCRIPTOR' : _HELLOREQUEST,
+  '__module__' : 'hellostreamingworld_pb2'
+  # @@protoc_insertion_point(class_scope:hellostreamingworld.HelloRequest)
+  })
+_sym_db.RegisterMessage(HelloRequest)
+
+HelloReply = _reflection.GeneratedProtocolMessageType('HelloReply', (_message.Message,), {
+  'DESCRIPTOR' : _HELLOREPLY,
+  '__module__' : 'hellostreamingworld_pb2'
+  # @@protoc_insertion_point(class_scope:hellostreamingworld.HelloReply)
+  })
+_sym_db.RegisterMessage(HelloReply)
+
+
+
+_MULTIGREETER = _descriptor.ServiceDescriptor(
+  name='MultiGreeter',
+  full_name='hellostreamingworld.MultiGreeter',
+  file=DESCRIPTOR,
+  index=0,
+  serialized_options=None,
+  create_key=_descriptor._internal_create_key,
+  serialized_start=134,
+  serialized_end=232,
+  methods=[
+  _descriptor.MethodDescriptor(
+    name='sayHello',
+    full_name='hellostreamingworld.MultiGreeter.sayHello',
+    index=0,
+    containing_service=None,
+    input_type=_HELLOREQUEST,
+    output_type=_HELLOREPLY,
+    serialized_options=None,
+    create_key=_descriptor._internal_create_key,
+  ),
+])
+_sym_db.RegisterServiceDescriptor(_MULTIGREETER)
+
+DESCRIPTOR.services_by_name['MultiGreeter'] = _MULTIGREETER
+
+# @@protoc_insertion_point(module_scope)

examples/python/hellostreamingworld/hellostreamingworld_pb2_grpc.py

@@ -0,0 +1,70 @@
+# Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT!
+"""Client and server classes corresponding to protobuf-defined services."""
+import grpc
+
+import hellostreamingworld_pb2 as hellostreamingworld__pb2
+
+
+class MultiGreeterStub(object):
+    """The greeting service definition.
+    """
+
+    def __init__(self, channel):
+        """Constructor.
+
+        Args:
+            channel: A grpc.Channel.
+        """
+        self.sayHello = channel.unary_stream(
+                '/hellostreamingworld.MultiGreeter/sayHello',
+                request_serializer=hellostreamingworld__pb2.HelloRequest.SerializeToString,
+                response_deserializer=hellostreamingworld__pb2.HelloReply.FromString,
+                )
+
+
+class MultiGreeterServicer(object):
+    """The greeting service definition.
+    """
+
+    def sayHello(self, request, context):
+        """Sends multiple greetings
+        """
+        context.set_code(grpc.StatusCode.UNIMPLEMENTED)
+        context.set_details('Method not implemented!')
+        raise NotImplementedError('Method not implemented!')
+
+
+def add_MultiGreeterServicer_to_server(servicer, server):
+    rpc_method_handlers = {
+            'sayHello': grpc.unary_stream_rpc_method_handler(
+                    servicer.sayHello,
+                    request_deserializer=hellostreamingworld__pb2.HelloRequest.FromString,
+                    response_serializer=hellostreamingworld__pb2.HelloReply.SerializeToString,
+            ),
+    }
+    generic_handler = grpc.method_handlers_generic_handler(
+            'hellostreamingworld.MultiGreeter', rpc_method_handlers)
+    server.add_generic_rpc_handlers((generic_handler,))
+
+
+ # This class is part of an EXPERIMENTAL API.
+class MultiGreeter(object):
+    """The greeting service definition.
+    """
+
+    @staticmethod
+    def sayHello(request,
+            target,
+            options=(),
+            channel_credentials=None,
+            call_credentials=None,
+            insecure=False,
+            compression=None,
+            wait_for_ready=None,
+            timeout=None,
+            metadata=None):
+        return grpc.experimental.unary_stream(request, target, '/hellostreamingworld.MultiGreeter/sayHello',
+            hellostreamingworld__pb2.HelloRequest.SerializeToString,
+            hellostreamingworld__pb2.HelloReply.FromString,
+            options, channel_credentials,
+            insecure, call_credentials, compression, wait_for_ready, timeout, metadata)