Create a base class for clients

Author: lidizheng

gapic/templates/%namespace/%name_%version/%sub/services/%service/async_client.py.j2

@@ -22,9 +22,9 @@ from google.oauth2 import service_account              # type: ignore
 {% endfilter %}
 from .transports.base import {{ service.name }}Transport
 from .transports.grpc_asyncio import {{ service.name }}GrpcAsyncIOTransport
+from .base_client import {{ service.name }}BaseClient, {{ service.name }}BaseClientMeta
 
-
-class {{ service.async_client_name }}Meta(type):
+class {{ service.async_client_name }}Meta({{ service.name }}BaseClientMeta):
     """Metaclass for the {{ service.name }} client.
 
     This provides class-level methods for building and retrieving
@@ -55,149 +55,13 @@ class {{ service.async_client_name }}Meta(type):
         return next(iter(cls._transport_registry.values()))
 
 
-class {{ service.async_client_name }}(metaclass={{ service.async_client_name }}Meta):
+class {{ service.async_client_name }}({{ service.name }}BaseClient, metaclass={{ service.async_client_name }}Meta):
     """{{ service.meta.doc|rst(width=72, indent=4) }}"""
 
-    @staticmethod
-    def _get_default_mtls_endpoint(api_endpoint):
-        """Convert api endpoint to mTLS endpoint.
-        Convert "*.sandbox.googleapis.com" and "*.googleapis.com" to
-        "*.mtls.sandbox.googleapis.com" and "*.mtls.googleapis.com" respectively.
-        Args:
-            api_endpoint (Optional[str]): the api endpoint to convert.
-        Returns:
-            str: converted mTLS api endpoint.
-        """
-        if not api_endpoint:
-            return api_endpoint
-
-        mtls_endpoint_re = re.compile(
-            r"(?P<name>[^.]+)(?P<mtls>\.mtls)?(?P<sandbox>\.sandbox)?(?P<googledomain>\.googleapis\.com)?"
-        )
-
-        m = mtls_endpoint_re.match(api_endpoint)
-        name, mtls, sandbox, googledomain = m.groups()
-        if mtls or not googledomain:
-            return api_endpoint
-
-        if sandbox:
-            return api_endpoint.replace(
-                "sandbox.googleapis.com", "mtls.sandbox.googleapis.com"
-            )
-
-        return api_endpoint.replace(".googleapis.com", ".mtls.googleapis.com")
-
-    DEFAULT_ENDPOINT = {% if service.host %}'{{ service.host }}'{% else %}None{% endif %}
-    DEFAULT_MTLS_ENDPOINT = _get_default_mtls_endpoint.__func__(  # type: ignore
-        DEFAULT_ENDPOINT
-    )
-    DEFAULT_MTLS_TRANSPORT = {{ service.grpc_asyncio_transport_name }}
-
     @classmethod
-    def from_service_account_file(cls, filename: str, *args, **kwargs):
-        """Creates an instance of this client using the provided credentials
-        file.
-
-        Args:
-            filename (str): The path to the service account private key json
-                file.
-            args: Additional arguments to pass to the constructor.
-            kwargs: Additional arguments to pass to the constructor.
-
-        Returns:
-            {@api.name}: The constructed client.
-        """
-        credentials = service_account.Credentials.from_service_account_file(
-            filename)
-        kwargs['credentials'] = credentials
-        return cls(*args, **kwargs)
-
-    from_service_account_json = from_service_account_file
-
-
-    {% for message in service.resource_messages -%}
-    @staticmethod
-    def {{ message.resource_type|snake_case }}_path({% for arg in message.resource_path_args %}{{ arg }}: str,{% endfor %}) -> str:
-        """Return a fully-qualified {{ message.resource_type|snake_case }} string."""
-        return "{{ message.resource_path }}".format({% for arg in message.resource_path_args %}{{ arg }}={{ arg }}, {% endfor %})
-
-    {% endfor %}
-
-    def __init__(self, *,
-            credentials: credentials.Credentials = None,
-            transport: Union[str, {{ service.name }}Transport] = None,
-            client_options: ClientOptions = None,
-            ) -> None:
-        """Instantiate the {{ (service.client_name|snake_case).replace('_', ' ') }}.
-
-        Args:
-            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.
-            transport (Union[str, ~.{{ service.name }}Transport]): The
-                transport to use. If set to None, a transport is chosen
-                automatically.
-            client_options (ClientOptions): Custom options for the client.
-                (1) The ``api_endpoint`` property can be used to override the
-                default endpoint provided by the client.
-                (2) If ``transport`` argument is None, ``client_options`` can be
-                used to create a mutual TLS transport. If ``client_cert_source``
-                is provided, mutual TLS transport will be created with the given
-                ``api_endpoint`` or the default mTLS endpoint, and the client
-                SSL credentials obtained from ``client_cert_source``.
-
-        Raises:
-            google.auth.exceptions.MutualTlsChannelError: If mutual TLS transport
-                creation failed for any reason.
-        """
-        if isinstance(client_options, dict):
-            client_options = ClientOptions.from_dict(client_options)
-
-        # Save or instantiate the transport.
-        # Ordinarily, we provide the transport, but allowing a custom transport
-        # instance provides an extensibility point for unusual situations.
-        if isinstance(transport, {{ service.name }}Transport):
-            # transport is a {{ service.name }}Transport instance.
-            if credentials:
-                raise ValueError('When providing a transport instance, '
-                                 'provide its credentials directly.')
-            self._transport = transport
-        elif client_options is None or (
-            client_options.api_endpoint == None
-            and client_options.client_cert_source is None
-        ):
-            # Don't trigger mTLS if we get an empty ClientOptions.
-            Transport = type(self).get_transport_class(transport)
-            self._transport = Transport(
-                credentials=credentials, host=self.DEFAULT_ENDPOINT
-            )
-        else:
-            # We have a non-empty ClientOptions. If client_cert_source is
-            # provided, trigger mTLS with user provided endpoint or the default
-            # mTLS endpoint.
-            if client_options.client_cert_source:
-                api_mtls_endpoint = (
-                    client_options.api_endpoint
-                    if client_options.api_endpoint
-                    else self.DEFAULT_MTLS_ENDPOINT
-                )
-            else:
-                api_mtls_endpoint = None
-
-            api_endpoint = (
-                client_options.api_endpoint
-                if client_options.api_endpoint
-                else self.DEFAULT_ENDPOINT
-            )
-
-            self._transport = self.DEFAULT_MTLS_TRANSPORT(
-                credentials=credentials,
-                host=api_endpoint,
-                api_mtls_endpoint=api_mtls_endpoint,
-                client_cert_source=client_options.client_cert_source,
-            )
+    def _default_mtls_transport(cls) -> str:
+        """Returns the default MTLS transport name."""
+        return "grpc_asyncio"
 
     {% for method in service.methods.values() -%}
     {% if not method.server_streaming %}async {% endif -%}def {{ method.name|snake_case }}(self,
@@ -312,7 +176,7 @@ class {{ service.async_client_name }}(metaclass={{ service.async_client_name }}M
             ),
             {%- endif %}
             default_timeout={{ method.timeout }},
-            client_info=_client_info,
+            client_info=self._client_info,
         )
         {%- if method.field_headers %}
 
@@ -367,16 +231,6 @@ class {{ service.async_client_name }}(metaclass={{ service.async_client_name }}M
     {% endfor %}
 
 
-try:
-    _client_info = gapic_v1.client_info.ClientInfo(
-        gapic_version=pkg_resources.get_distribution(
-            '{{ api.naming.warehouse_package_name }}',
-        ).version,
-    )
-except pkg_resources.DistributionNotFound:
-    _client_info = gapic_v1.client_info.ClientInfo()
-
-
 __all__ = (
     '{{ service.async_client_name }}',
 )