googleapis · chalmerlowe · Aug 27, 2026 · Aug 27, 2026 · Aug 28, 2026 · Aug 31, 2026
@@ -35,17 +35,16 @@
 )
 
 import google.protobuf
+from google.api_core import _observability, gapic_v1
 from google.api_core import client_options as client_options_lib
 from google.api_core import exceptions as core_exceptions
-from google.api_core import gapic_v1
 from google.api_core import retry as retries
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.auth.exceptions import MutualTLSChannelError  # type: ignore
 from google.auth.transport import mtls  # type: ignore
 from google.auth.transport.grpc import SslCredentials  # type: ignore
-from google.oauth2 import service_account  # type: ignore
-
 from google.cloud.secretmanager_v1 import gapic_version as package_version
+from google.oauth2 import service_account  # type: ignore
 
 try:
     OptionalRetry = Union[retries.Retry, gapic_v1.method._MethodDefault, None]
@@ -68,7 +67,6 @@
 import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
 import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 from google.cloud.location import locations_pb2  # type: ignore
-
 from google.cloud.secretmanager_v1.services.secret_manager_service import pagers
 from google.cloud.secretmanager_v1.types import resources, service
 
@@ -746,17 +744,28 @@ def __init__(
                 else cast(Callable[..., SecretManagerServiceTransport], transport)
             )
             # initialize with the provided callable or the passed in class
-            self._transport = transport_init(
-                credentials=credentials,
-                credentials_file=self._client_options.credentials_file,
-                host=self._api_endpoint,
-                scopes=self._client_options.scopes,
-                client_cert_source_for_mtls=self._client_cert_source,
-                quota_project_id=self._client_options.quota_project_id,
-                client_info=client_info,
-                always_use_jwt_access=True,
-                api_audience=self._client_options.api_audience,
-            )
+            transport_kwargs = {
+                "credentials": credentials,
+                "credentials_file": self._client_options.credentials_file,
+                "host": self._api_endpoint,
+                "scopes": self._client_options.scopes,
+                "client_cert_source_for_mtls": self._client_cert_source,
+                "quota_project_id": self._client_options.quota_project_id,
+                "client_info": client_info,
+                "always_use_jwt_access": True,
+                "api_audience": self._client_options.api_audience,
+            }
+
+            # When OpenTelemetry tracing is enabled, obtain the channel interceptor
+            # and pass it to the transport.
+            if transport_init is SecretManagerServiceGrpcTransport:
+                otel_interceptor = _observability.get_otel_interceptor(
+                    self._client_options
+                )
+                if otel_interceptor is not None:
+                    transport_kwargs["interceptors"] = [otel_interceptor]
+
+            self._transport = transport_init(**transport_kwargs)
 
         if "async" not in str(self._transport):
             if CLIENT_LOGGING_SUPPORTED and _LOGGER.isEnabledFor(

@@ -27,12 +27,12 @@
 import grpc  # type: ignore
 import proto  # type: ignore
 from google.api_core import gapic_v1, grpc_helpers
+from google.api_core.grpc_helpers import ClientInterceptor
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.auth.transport.grpc import SslCredentials  # type: ignore
 from google.cloud.location import locations_pb2  # type: ignore
-from google.protobuf.json_format import MessageToJson
-
 from google.cloud.secretmanager_v1.types import resources, service
+from google.protobuf.json_format import MessageToJson
 
 from .base import DEFAULT_CLIENT_INFO, SecretManagerServiceTransport
 
@@ -148,6 +148,14 @@ def __init__(
         client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
         always_use_jwt_access: Optional[bool] = False,
         api_audience: Optional[str] = None,
+        interceptors: Optional[
+            Sequence[
+                Union[
+                    ClientInterceptor,
+                    Callable[[grpc.Channel], grpc.Channel],
+                ]
+            ]
+        ] = None,
     ) -> None:
         """Instantiate the transport.
 
@@ -198,6 +206,9 @@ def __init__(
                 to the service that will be set when using certain 3rd party
                 authentication flows. Audience is typically a resource identifier.
                 If not set, the host value will be used as a default.
+            interceptors (Optional[Sequence[Union[ClientInterceptor, Callable[[grpc.Channel], grpc.Channel]]]]):
+                Additional interceptors (or callables that apply interceptors) to apply to the
+                gRPC channel.
 
         Raises:
           google.auth.exceptions.MutualTLSChannelError: If mutual TLS transport
@@ -274,6 +285,10 @@ def __init__(
                 ],
             )
 
+        self._grpc_channel = grpc_helpers.apply_channel_interceptors(
+            self._grpc_channel, interceptors
+        )
+
         self._interceptor = _LoggingClientInterceptor()
         self._logged_channel = grpc.intercept_channel(
             self._grpc_channel, self._interceptor

@@ -71,7 +71,9 @@
     "pytest-asyncio",
 ]
 UNIT_TEST_EXTERNAL_DEPENDENCIES: List[str] = []
-UNIT_TEST_LOCAL_DEPENDENCIES: List[str] = []
+UNIT_TEST_LOCAL_DEPENDENCIES: List[str] = [
+    "../google-api-core[tracing,testing]",
+]
 UNIT_TEST_DEPENDENCIES: List[str] = []
 UNIT_TEST_EXTRAS: List[str] = []
 UNIT_TEST_EXTRAS_BY_PYTHON: Dict[str, List[str]] = {}

@@ -44,7 +44,7 @@
     release_status = "Development Status :: 5 - Production/Stable"
 
 dependencies = [
-    "google-api-core[grpc] >= 2.25.0, <3.0.0",
+    "google-api-core[grpc] >= 2.35.0, <3.0.0",
     # Exclude incompatible versions of `google-auth`
     # See https://github.com/googleapis/google-cloud-python/issues/12364
     "google-auth >= 2.14.1, <3.0.0,!=2.24.0,!=2.25.0",

@@ -4,7 +4,7 @@
 # pinning their versions to their lower bounds.
 # For example, if setup.py has "google-cloud-foo >= 1.14.0, < 2.0.0",
 # then this file should have google-cloud-foo==1.14.0
-google-api-core==2.25.0
+google-api-core==2.35.0
 google-auth==2.14.1
 grpcio==1.59.0
 proto-plus==1.26.1

@@ -14,6 +14,7 @@
 # limitations under the License.
 #
 import asyncio
+import functools
 import json
 import math
 import os
@@ -61,15 +62,14 @@
 from google.auth import credentials as ga_credentials
 from google.auth.exceptions import MutualTLSChannelError
 from google.cloud.location import locations_pb2
-from google.oauth2 import service_account
-
 from google.cloud.secretmanager_v1.services.secret_manager_service import (
     SecretManagerServiceAsyncClient,
     SecretManagerServiceClient,
     pagers,
     transports,
 )
 from google.cloud.secretmanager_v1.types import resources, service
+from google.oauth2 import service_account
 
 CRED_INFO_JSON = {
     "credential_source": "/path/to/file",
@@ -770,6 +770,103 @@ def test_secret_manager_service_client_client_options(
         )
 
 
+def test_secret_manager_service_client_otel_channel_injection_enabled():
+    """Proves that when OpenTelemetry tracing is enabled:
+
+    1. SecretManagerServiceClient obtains the channel interceptor via
+       _observability.get_otel_interceptor passing client_options.
+    2. The interceptor is passed into transport kwargs under 'interceptors',
+       allowing the Transport to apply it via apply_channel_interceptors.
+    """
+    mock_interceptor = mock.Mock()
+    with (
+        mock.patch(
+            "google.cloud.secretmanager_v1.services.secret_manager_service.client._observability.get_otel_interceptor",
+            return_value=mock_interceptor,
+        ) as mock_get_interceptor,
+        mock.patch.object(
+            transports.SecretManagerServiceGrpcTransport, "__init__", return_value=None
+        ) as patched_transport_init,
+    ):
+        client = SecretManagerServiceClient(transport="grpc")
+
+        mock_get_interceptor.assert_called_once_with(client._client_options)
+        called_kwargs = patched_transport_init.call_args.kwargs
+        assert "interceptors" in called_kwargs
+        assert called_kwargs["interceptors"] == [mock_interceptor]
+
+
+def test_secret_manager_service_client_otel_channel_injection_disabled():
+    """Proves that when OpenTelemetry tracing is disabled:
+
+    1. SecretManagerServiceClient checks for an OTel interceptor and receives None.
+    2. No 'interceptors' argument is passed to the transport constructor.
+    """
+    with (
+        mock.patch(
+            "google.cloud.secretmanager_v1.services.secret_manager_service.client._observability.get_otel_interceptor",
+            return_value=None,
+        ) as mock_get_interceptor,
+        mock.patch.object(
+            transports.SecretManagerServiceGrpcTransport, "__init__", return_value=None
+        ) as patched_transport_init,
+    ):
+        client = SecretManagerServiceClient(transport="grpc")
+
+        mock_get_interceptor.assert_called_once_with(client._client_options)
+        called_kwargs = patched_transport_init.call_args.kwargs
+        assert "interceptors" not in called_kwargs
+
+
+def test_secret_manager_service_grpc_transport_interceptors():
+    """Proves that SecretManagerServiceGrpcTransport accepts channel interceptors
+    and invokes grpc_helpers.apply_channel_interceptors to apply them to the underlying
+    gRPC channel.
+    """
+    mock_interceptor = mock.Mock()
+    mock_channel = mock.Mock()
+
+    with (
+        mock.patch.object(
+            transports.SecretManagerServiceGrpcTransport,
+            "create_channel",
+            return_value=mock_channel,
+        ),
+        mock.patch(
+            "google.api_core.grpc_helpers.apply_channel_interceptors",
+            return_value=mock_channel,
+        ) as mock_apply_interceptors,
+    ):
+        transports.SecretManagerServiceGrpcTransport(
+            interceptors=[mock_interceptor],
+        )
+
+        mock_apply_interceptors.assert_called_once_with(
+            mock_channel, [mock_interceptor]
+        )
+
+
+def test_secret_manager_service_grpc_transport_custom_channel_interceptors():
+    """Proves that SecretManagerServiceGrpcTransport wraps explicitly passed custom channels
+    using grpc_helpers.apply_channel_interceptors.
+    """
+    mock_interceptor = mock.Mock()
+    mock_custom_channel = mock.Mock(spec=grpc.Channel)
+
+    with mock.patch(
+        "google.api_core.grpc_helpers.apply_channel_interceptors",
+        return_value=mock_custom_channel,
+    ) as mock_apply_interceptors:
+        transports.SecretManagerServiceGrpcTransport(
+            channel=mock_custom_channel,
+            interceptors=[mock_interceptor],
+        )
+
+        mock_apply_interceptors.assert_called_once_with(
+            mock_custom_channel, [mock_interceptor]
+        )
+
+
 @pytest.mark.parametrize(
     "client_class,transport_class,transport_name,use_client_cert_env",
     [