Only use config server if GDA didn't supply params

src/mx_bluesky/hyperion/external_interaction/config_server.py

@@ -17,9 +17,9 @@ def config_server() -> ConfigServer:
 class FeatureFlags(BaseModel):
     # The default value will be used as the fallback when doing a best-effort fetch
     # from the service
-    use_panda_for_gridscan: bool = False
-    use_gpu_for_gridscan: bool = False
-    set_stub_offsets: bool = False
+    use_panda_for_gridscan: bool = CONST.I03.USE_PANDA_FOR_GRIDSCAN
+    use_gpu_for_gridscan: bool = CONST.I03.USE_PANDA_FOR_GRIDSCAN
+    set_stub_offsets: bool = CONST.I03.SET_STUB_OFFSETS
 
     @classmethod
     def _get_flags(cls):

src/mx_bluesky/hyperion/parameters/constants.py

@@ -114,6 +114,7 @@ class I03Constants:
     USE_PANDA_FOR_GRIDSCAN = False
     USE_GPU_FOR_GRIDSCAN_ANALYSIS = False
     THAWING_TIME = 20
+    SET_STUB_OFFSETS = False
 
 
 @dataclass(frozen=True)

src/mx_bluesky/hyperion/parameters/gridscan.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import os
+from typing import Any
 
 from dodal.devices.aperturescatterguard import ApertureValue
 from dodal.devices.detector import (
@@ -10,10 +11,11 @@
     PandAGridScanParams,
     ZebraGridScanParams,
 )
-from pydantic import Field, PrivateAttr
+from pydantic import Field, PrivateAttr, model_validator
 from scanspec.core import Path as ScanPath
 from scanspec.specs import Line, Static
 
+from mx_bluesky.hyperion.external_interaction.config_server import FeatureFlags
 from mx_bluesky.hyperion.parameters.components import (
     DiffractionExperimentWithSample,
     IspybExperimentType,
@@ -29,19 +31,29 @@
 class GridCommon(
     DiffractionExperimentWithSample, OptionalGonioAngleStarts, WithOavCentring
 ):
+    use_panda: bool
+    use_gpu: bool
     grid_width_um: float = Field(default=CONST.PARAM.GRIDSCAN.WIDTH_UM)
     exposure_time_s: float = Field(default=CONST.PARAM.GRIDSCAN.EXPOSURE_TIME_S)
     use_roi_mode: bool = Field(default=CONST.PARAM.GRIDSCAN.USE_ROI)
     panda_runup_distance_mm: float = Field(
         default=CONST.HARDWARE.PANDA_FGS_RUN_UP_DEFAULT
     )
-    use_panda: bool = Field(default=CONST.I03.USE_PANDA_FOR_GRIDSCAN)
-    use_gpu: bool = Field(default=CONST.I03.USE_GPU_FOR_GRIDSCAN_ANALYSIS)
     ispyb_experiment_type: IspybExperimentType = Field(
         default=IspybExperimentType.GRIDSCAN_3D
     )
     selected_aperture: ApertureValue | None = Field(default=ApertureValue.SMALL)
 
+    @model_validator(mode="before")
+    @classmethod
+    def set_default_feature_flags(cls, values) -> Any:
+        cls.features = FeatureFlags()
+        if "use_panda" not in values:
+            values["use_panda"] = cls.features.best_effort().use_panda_for_gridscan
+        if "use_gpu" not in values:
+            values["use_gpu"] = cls.features.best_effort().use_gpu_for_gridscan
+        return values
+
     @property
     def detector_params(self):
         self.det_dist_to_beam_converter_path = (

tests/unit_tests/hyperion/parameters/test_parameter_model.py

@@ -121,3 +121,14 @@ def test_selected_aperture_uses_default():
     raw_params["selected_aperture"] = None
     params = RotationScan(**raw_params)
     assert params.selected_aperture == ApertureValue.LARGE
+
+
+def test_feature_flags_overriden_if_supplied(minimal_3d_gridscan_params):
+    test_params = ThreeDGridScan(**minimal_3d_gridscan_params)
+    assert test_params.use_panda is False
+    assert test_params.use_gpu is False
+    minimal_3d_gridscan_params["use_panda"] = True
+    minimal_3d_gridscan_params["use_gpu"] = True
+    test_params = ThreeDGridScan(**minimal_3d_gridscan_params)
+    assert test_params.use_gpu
+    assert test_params.use_panda