Remove the parent class for grpc transports

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 %}
 
 

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 %}
 
 

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 %}