Remove the parent class for grpc transports

lidizheng · lidizheng · commit e17602057ae8 · 2020-04-17T14:09:51.000-07:00
diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/base.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/base.py.j2
@@ -30,6 +30,7 @@ class {{ service.name }}Transport(abc.ABC):
             self, *,
             host: str{% if service.host %} = '{{ service.host }}'{% endif %},
             credentials: credentials.Credentials = None,
+            **kwargs,
             ) -> None:
         """Instantiate the transport.
 
@@ -59,7 +60,7 @@ class {{ service.name }}Transport(abc.ABC):
     @property
     def operations_client(self) -> operations_v1.OperationsClient:
         """Return the client designed to process long-running operations."""
-        raise NotImplementedError
+        raise NotImplementedError()
     {%- endif %}
     {%- for method in service.methods.values() %}
 
@@ -70,7 +71,7 @@ class {{ service.name }}Transport(abc.ABC):
                 {{ method.output.ident }},
                 typing.Awaitable[{{ method.output.ident }}]
             ]]:
-        raise NotImplementedError
+        raise NotImplementedError()
     {%- endfor %}
 
 
diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc.py.j2
@@ -19,10 +19,10 @@ import grpc  # type: ignore
 {{ method.output.ident.python_import }}
 {% endfor -%}
 {% endfilter %}
-from .grpc_base import {{ service.name }}GrpcBaseTransport
+from .base import {{ service.name }}Transport
 
 
-class {{ service.name }}GrpcTransport({{ service.name }}GrpcBaseTransport[grpc.Channel]):
+class {{ service.name }}GrpcTransport({{ service.name }}Transport):
     """gRPC backend transport for {{ service.name }}.
 
     {{ service.meta.doc|rst(width=72, indent=4) }}
@@ -34,6 +34,71 @@ class {{ service.name }}GrpcTransport({{ service.name }}GrpcBaseTransport[grpc.C
     It sends protocol buffers over the wire using gRPC (which is built on
     top of HTTP/2); the ``grpcio`` package must be installed.
     """
+    _stubs: Dict[str, Callable]
+
+    def __init__(self, *,
+            host: str{% if service.host %} = '{{ service.host }}'{% endif %},
+            credentials: credentials.Credentials = None,
+            channel: grpc.Channel = None,
+            api_mtls_endpoint: str = None,
+            client_cert_source: Callable[[], Tuple[bytes, bytes]] = None) -> None:
+        """Instantiate the transport.
+
+        Args:
+            host ({% if service.host %}Optional[str]{% else %}str{% endif %}):
+                {{- ' ' }}The hostname to connect to.
+            credentials (Optional[google.auth.credentials.Credentials]): The
+                authorization credentials to attach to requests. These
+                credentials identify the application to the service; if none
+                are specified, the client will attempt to ascertain the
+                credentials from the environment.
+                This argument is ignored if ``channel`` is provided.
+            channel (Optional[grpc.Channel]): A ``Channel`` instance through
+                which to make calls.
+            api_mtls_endpoint (Optional[str]): The mutual TLS endpoint. If
+                provided, it overrides the ``host`` argument and tries to create
+                a mutual TLS channel with client SSL credentials from
+                ``client_cert_source`` or applicatin default SSL credentials.
+            client_cert_source (Optional[Callable[[], Tuple[bytes, bytes]]]): A
+                callback to provide client SSL certificate bytes and private key
+                bytes, both in PEM format. It is ignored if ``api_mtls_endpoint``
+                is None.
+
+        Raises:
+            google.auth.exceptions.MutualTlsChannelError: If mutual TLS transport
+                creation failed for any reason.
+        """
+        if channel:
+            # Sanity check: Ensure that channel and credentials are not both
+            # provided.
+            credentials = False
+
+            # If a channel was explicitly provided, set it.
+            self._grpc_channel = channel
+        elif api_mtls_endpoint:
+            host = api_mtls_endpoint if ":" in api_mtls_endpoint else api_mtls_endpoint + ":443"
+
+            # Create SSL credentials with client_cert_source or application
+            # default SSL credentials.
+            if client_cert_source:
+                cert, key = client_cert_source()
+                ssl_credentials = grpc.ssl_channel_credentials(
+                    certificate_chain=cert, private_key=key
+                )
+            else:
+                ssl_credentials = SslCredentials().ssl_credentials
+
+            # create a new channel. The provided one is ignored.
+            self._grpc_channel = type(self).create_channel(
+                host,
+                credentials=credentials,
+                ssl_credentials=ssl_credentials,
+                scopes=self.AUTH_SCOPES,
+            )
+
+        # Run the base constructor.
+        super().__init__(host=host, credentials=credentials)
+        self._stubs = {}  # type: Dict[str, Callable]
 
     @classmethod
     def create_channel(cls,
@@ -66,6 +131,23 @@ class {{ service.name }}GrpcTransport({{ service.name }}GrpcBaseTransport[grpc.C
             **kwargs
         )
 
+    @property
+    def grpc_channel(self) -> grpc.Channel:
+        """Create the channel designed to connect to this service.
+
+        This property caches on the instance; repeated calls return
+        the same channel.
+        """
+        # Sanity check: Only create a new channel if we do not already
+        # have one.
+        if not hasattr(self, '_grpc_channel'):
+            self._grpc_channel = self.create_channel(
+                self._host,
+                credentials=self._credentials,
+            )
+
+        # Return the channel from cache.
+        return self._grpc_channel
     {%- if service.has_lro %}
 
     @property
@@ -103,7 +185,17 @@ class {{ service.name }}GrpcTransport({{ service.name }}GrpcBaseTransport[grpc.C
                 A function that, when called, will call the underlying RPC
                 on the server.
         """
-        return super().{{ method.name|snake_case }}
+        # Generate a "stub function" on-the-fly which will actually make
+        # the request.
+        # gRPC handles serialization and deserialization, so we just need
+        # to pass in the functions for each.
+        if '{{ method.name|snake_case }}' not in self._stubs:
+            self._stubs['{{ method.name|snake_case }}'] = self.grpc_channel.{{ method.grpc_stub_type }}(
+                '/{{ '.'.join(method.meta.address.package) }}.{{ service.name }}/{{ method.name }}',
+                request_serializer={{ method.input.ident }}.{% if method.input.ident.python_import.module.endswith('_pb2') %}SerializeToString{% else %}serialize{% endif %},
+                response_deserializer={{ method.output.ident }}.{% if method.output.ident.python_import.module.endswith('_pb2') %}FromString{% else %}deserialize{% endif %},
+            )
+        return self._stubs['{{ method.name|snake_case }}']
     {%- endfor %}
 
 
diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_asyncio.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_asyncio.py.j2
@@ -3,12 +3,14 @@
 {% block content %}
 from typing import Awaitable, Callable, Dict, Sequence, Tuple
 
-from google.api_core import grpc_helpers_async   # type: ignore
+from google.api_core import grpc_helpers_async         # type: ignore
 {%- if service.has_lro %}
-from google.api_core import operations_v1  # type: ignore
+from google.api_core import operations_v1              # type: ignore
 {%- endif %}
-from google.auth import credentials        # type: ignore
+from google.auth import credentials                    # type: ignore
+from google.auth.transport.grpc import SslCredentials  # type: ignore
 
+import grpc                        # type: ignore
 from grpc.experimental import aio  # type: ignore
 
 {% filter sort_lines -%}
@@ -17,10 +19,11 @@ from grpc.experimental import aio  # type: ignore
 {{ method.output.ident.python_import }}
 {% endfor -%}
 {% endfilter %}
-from .grpc_base import {{ service.name }}GrpcBaseTransport
+from .base import {{ service.name }}Transport
+from .grpc import {{ service.name }}GrpcTransport
 
 
-class {{ service.grpc_asyncio_transport_name }}({{ service.name }}GrpcBaseTransport[aio.Channel]):
+class {{ service.grpc_asyncio_transport_name }}({{ service.name }}Transport):
     """gRPC AsyncIO backend transport for {{ service.name }}.
 
     {{ service.meta.doc|rst(width=72, indent=4) }}
@@ -33,6 +36,9 @@ class {{ service.grpc_asyncio_transport_name }}({{ service.name }}GrpcBaseTransp
     top of HTTP/2); the ``grpcio`` package must be installed.
     """
 
+    _grpc_channel: aio.Channel
+    _stubs: Dict[str, Callable] = {}
+
     @classmethod
     def create_channel(cls,
                        host: str{% if service.host %} = '{{ service.host }}'{% endif %},
@@ -64,6 +70,87 @@ class {{ service.grpc_asyncio_transport_name }}({{ service.name }}GrpcBaseTransp
             **kwargs
         )
 
+    def __init__(self, *,
+            host: str{% if service.host %} = '{{ service.host }}'{% endif %},
+            credentials: credentials.Credentials = None,
+            channel: aio.Channel = None,
+            api_mtls_endpoint: str = None,
+            client_cert_source: Callable[[], Tuple[bytes, bytes]] = None) -> None:
+        """Instantiate the transport.
+
+        Args:
+            host ({% if service.host %}Optional[str]{% else %}str{% endif %}):
+                {{- ' ' }}The hostname to connect to.
+            credentials (Optional[google.auth.credentials.Credentials]): The
+                authorization credentials to attach to requests. These
+                credentials identify the application to the service; if none
+                are specified, the client will attempt to ascertain the
+                credentials from the environment.
+                This argument is ignored if ``channel`` is provided.
+            channel (Optional[aio.Channel]): A ``Channel`` instance through
+                which to make calls.
+            api_mtls_endpoint (Optional[str]): The mutual TLS endpoint. If
+                provided, it overrides the ``host`` argument and tries to create
+                a mutual TLS channel with client SSL credentials from
+                ``client_cert_source`` or applicatin default SSL credentials.
+            client_cert_source (Optional[Callable[[], Tuple[bytes, bytes]]]): A
+                callback to provide client SSL certificate bytes and private key
+                bytes, both in PEM format. It is ignored if ``api_mtls_endpoint``
+                is None.
+
+        Raises:
+          google.auth.exceptions.MutualTlsChannelError: If mutual TLS transport
+              creation failed for any reason.
+        """
+        if channel:
+            # Sanity check: Ensure that channel and credentials are not both
+            # provided.
+            credentials = False
+
+            # If a channel was explicitly provided, set it.
+            self._grpc_channel = channel
+        elif api_mtls_endpoint:
+            host = api_mtls_endpoint if ":" in api_mtls_endpoint else api_mtls_endpoint + ":443"
+
+            # Create SSL credentials with client_cert_source or application
+            # default SSL credentials.
+            if client_cert_source:
+                cert, key = client_cert_source()
+                ssl_credentials = grpc.ssl_channel_credentials(
+                    certificate_chain=cert, private_key=key
+                )
+            else:
+                ssl_credentials = SslCredentials().ssl_credentials
+
+            # create a new channel. The provided one is ignored.
+            self._grpc_channel = type(self).create_channel(
+                host,
+                credentials=credentials,
+                ssl_credentials=ssl_credentials,
+                scopes=self.AUTH_SCOPES,
+            )
+
+        # Run the base constructor.
+        super().__init__(host=host, credentials=credentials)
+        self._stubs = {}
+
+    @property
+    def grpc_channel(self) -> aio.Channel:
+        """Create the channel designed to connect to this service.
+
+        This property caches on the instance; repeated calls return
+        the same channel.
+        """
+        # Sanity check: Only create a new channel if we do not already
+        # have one.
+        if not hasattr(self, '_grpc_channel'):
+            self._grpc_channel = self.create_channel(
+                self._host,
+                credentials=self._credentials,
+            )
+
+        # Return the channel from cache.
+        return self._grpc_channel
     {%- if service.has_lro %}
 
     @property
@@ -101,7 +188,17 @@ class {{ service.grpc_asyncio_transport_name }}({{ service.name }}GrpcBaseTransp
                 A function that, when called, will call the underlying RPC
                 on the server.
         """
-        return super().{{ method.name|snake_case }}
+        # Generate a "stub function" on-the-fly which will actually make
+        # the request.
+        # gRPC handles serialization and deserialization, so we just need
+        # to pass in the functions for each.
+        if '{{ method.name|snake_case }}' not in self._stubs:
+            self._stubs['{{ method.name|snake_case }}'] = self.grpc_channel.{{ method.grpc_stub_type }}(
+                '/{{ '.'.join(method.meta.address.package) }}.{{ service.name }}/{{ method.name }}',
+                request_serializer={{ method.input.ident }}.{% if method.input.ident.python_import.module.endswith('_pb2') %}SerializeToString{% else %}serialize{% endif %},
+                response_deserializer={{ method.output.ident }}.{% if method.output.ident.python_import.module.endswith('_pb2') %}FromString{% else %}deserialize{% endif %},
+            )
+        return self._stubs['{{ method.name|snake_case }}']
     {%- endfor %}
 
 
diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_base.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_base.py.j2
