feat(otel): implement eager channel wrapping (Variant B) for OTel compatibility

Author: chalmerlowe

packages/google-cloud-secret-manager/google/cloud/secretmanager_v1/services/secret_manager_service/client.py

@@ -743,15 +743,6 @@ def __init__(
                 if isinstance(transport, str) or transport is None
                 else cast(Callable[..., SecretManagerServiceTransport], transport)
             )
-            # Resolve interceptors for gRPC
-            interceptors = None
-            if transport_init is SecretManagerServiceGrpcTransport:
-                otel_interceptor = _otel_helpers.get_otel_grpc_interceptor(
-                    self._client_options
-                )
-                if otel_interceptor:
-                    interceptors = [otel_interceptor]
-
             # initialize with the provided callable or the passed in class
             transport_kwargs = {
                 "credentials": credentials,
@@ -764,8 +755,27 @@ def __init__(
                 "always_use_jwt_access": True,
                 "api_audience": self._client_options.api_audience,
             }
-            if interceptors is not None:
-                transport_kwargs["interceptors"] = interceptors
+
+            # 🎯 VARIANT B: Eager Channel Creation and Tracing Application
+            if transport_init is SecretManagerServiceGrpcTransport:
+                if _otel_helpers.is_otel_capabilities_enabled(self._client_options):
+                    # Eagerly create the channel using the Transport's classmethod
+                    raw_channel = transport_init.create_channel(
+                        self._api_endpoint,
+                        credentials=credentials,
+                        credentials_file=self._client_options.credentials_file,
+                        scopes=self._client_options.scopes,
+                        quota_project_id=self._client_options.quota_project_id,
+                    )
+
+                    # Apply OTel capabilities to the channel
+                    wrapped_channel = _otel_helpers.apply_otel_capabilities_to_channel(
+                        raw_channel,
+                        self._client_options
+                    )
+
+                    # Inject the wrapped channel into transport kwargs
+                    transport_kwargs["channel"] = wrapped_channel
 
             self._transport = transport_init(**transport_kwargs)
 

packages/google-cloud-secret-manager/tests/unit/gapic/secretmanager_v1/test_secret_manager_service.py

@@ -769,47 +769,60 @@ def test_secret_manager_service_client_client_options(
         )
 
 
-def test_secret_manager_service_client_otel_interceptor_injection():
-    # Mock the helper to return a sentinel interceptor
-    mock_interceptor = mock.Mock()
+def test_secret_manager_service_client_otel_eager_channel_injection():
+    # Mock the helpers to simulate OTel being enabled
+    mock_raw_channel = mock.Mock()
+    mock_wrapped_channel = mock.Mock()
 
     with mock.patch(
-        "google.cloud.secretmanager_v1.services.secret_manager_service.client._otel_helpers.get_otel_grpc_interceptor"
-    ) as mock_get_interceptor:
-        mock_get_interceptor.return_value = mock_interceptor
-
-        with mock.patch.object(
-            transports.SecretManagerServiceGrpcTransport, "__init__"
-        ) as patched_transport_init:
-            patched_transport_init.return_value = None
-
-            client = SecretManagerServiceClient(transport="grpc")
-
-            mock_get_interceptor.assert_called_once()
-
-            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_interceptor_injection_disabled():
-    # The helper does not return an interceptor
+        "google.cloud.secretmanager_v1.services.secret_manager_service.client._otel_helpers.is_otel_capabilities_enabled",
+        return_value=True
+    ) as mock_is_enabled:
+        with mock.patch(
+            "google.cloud.secretmanager_v1.services.secret_manager_service.client._otel_helpers.apply_otel_capabilities_to_channel",
+            return_value=mock_wrapped_channel
+        ) as mock_apply_otel:
+            with mock.patch.object(
+                transports.SecretManagerServiceGrpcTransport, "create_channel",
+                return_value=mock_raw_channel
+            ) as mock_create_channel:
+                with mock.patch.object(
+                    transports.SecretManagerServiceGrpcTransport, "__init__"
+                ) as patched_transport_init:
+                    patched_transport_init.return_value = None
+
+                    client = SecretManagerServiceClient(transport="grpc")
+
+                    mock_is_enabled.assert_called_once()
+                    mock_create_channel.assert_called_once()
+                    mock_apply_otel.assert_called_once_with(mock_raw_channel, mock.ANY)
+
+                    called_kwargs = patched_transport_init.call_args.kwargs
+                    assert "channel" in called_kwargs
+                    assert called_kwargs["channel"] == mock_wrapped_channel
+
+
+def test_secret_manager_service_client_otel_eager_channel_injection_disabled():
+    # Simulate OTel being disabled
     with mock.patch(
-        "google.cloud.secretmanager_v1.services.secret_manager_service.client._otel_helpers.get_otel_grpc_interceptor"
-    ) as mock_get_interceptor:
-        mock_get_interceptor.return_value = None
-
+        "google.cloud.secretmanager_v1.services.secret_manager_service.client._otel_helpers.is_otel_capabilities_enabled",
+        return_value=False
+    ) as mock_is_enabled:
         with mock.patch.object(
-            transports.SecretManagerServiceGrpcTransport, "__init__"
-        ) as patched_transport_init:
-            patched_transport_init.return_value = None
+            transports.SecretManagerServiceGrpcTransport, "create_channel"
+        ) as mock_create_channel:
+            with mock.patch.object(
+                transports.SecretManagerServiceGrpcTransport, "__init__"
+            ) as patched_transport_init:
+                patched_transport_init.return_value = None
 
-            client = SecretManagerServiceClient(transport="grpc")
+                client = SecretManagerServiceClient(transport="grpc")
 
-            mock_get_interceptor.assert_called_once()
+                mock_is_enabled.assert_called_once()
+                mock_create_channel.assert_not_called()
 
-            called_kwargs = patched_transport_init.call_args.kwargs
-            assert "interceptors" not in called_kwargs
+                called_kwargs = patched_transport_init.call_args.kwargs
+                assert "channel" not in called_kwargs
 
 
 @pytest.mark.parametrize(