Load deferred straylight data in Gen3.

Use straylight.check() method to determine if stray light correction
should be run.

python/lsst/obs/subaru/gen3/hsc/instrument.py

@@ -292,9 +292,9 @@ def ingestStrayLightData(self, butler, directory, *, transfer=None):
                                   storageClass="StrayLightData",
                                   universe=butler.registry.dimensions)
         for detector in self.getCamera():
-            path = os.path.join(directory, f"yBackground-{detector.getId():03d}.fits")
+            path = os.path.join(directory, f"ybackground-{detector.getId():03d}.fits")
             if not os.path.exists(path):
-                log.warn(f"No stray light data found for detector {detector.getId()}.")
+                log.warn(f"No stray light data found for detector {detector.getId()} @ {path}.")
                 continue
             ref = DatasetRef(datasetType, dataId={"instrument": self.getName(),
                                                   "detector": detector.getId(),
@@ -305,6 +305,6 @@ def ingestStrayLightData(self, butler, directory, *, transfer=None):
             butler.registry.registerDatasetType(datasetType)
             butler.registry.insertDimensionData("calibration_label", {"instrument": self.getName(),
                                                                       "name": calibrationLabel,
-                                                                      "datetime_begin": datetime.min,
+                                                                      "datetime_begin": datetime.date.min,
                                                                       "datetime_end": datetime_end})
-            butler.ingest(datasets, transfer=transfer)
+            butler.ingest(*datasets, transfer=transfer)

python/lsst/obs/subaru/strayLight/yStrayLight.py

@@ -56,18 +56,26 @@ def readIsrData(self, dataRef, rawExposure):
         # Note that this is run only in Gen2; in Gen3 we will rely on having
         # a proper butler-recognized dataset type with the right validity
         # ranges (though this has not yet been implemented).
-        detId = rawExposure.getDetector().getId()
-        if not self.checkFilter(rawExposure):
-            # No correction to be made
+        if not self.check(rawExposure):
             return None
+
+        return SubaruStrayLightData(dataRef.get("yBackground_filename")[0])
+
+    def check(self, exposure):
+        # Docstring inherited from StrayLightTask.check.
+        detId = exposure.getDetector().getId()
+        if not self.checkFilter(exposure):
+            # No correction to be made
+            return False
         if detId in range(104, 112):
             # No correction data: assume it's zero
-            return None
-        if rawExposure.getInfo().getVisitInfo().getDate().toPython() >= datetime.datetime(2018, 1, 1):
+            return False
+        if exposure.getInfo().getVisitInfo().getDate().toPython >= datetime.datetime(2018, 1, 1):
             # LEDs causing the stray light have been covered up.
             # We believe there is no remaining stray light.
-            return None
-        return SubaruStrayLightData(dataRef.get("yBackground_filename")[0])
+            return False
+
+        return True
 
     def run(self, exposure, strayLightData):
         """Subtract the y-band stray light
@@ -87,9 +95,14 @@ def run(self, exposure, strayLightData):
             An opaque object that contains any calibration data used to
             correct for stray light.
         """
+        if not self.check(exposure):
+            return None
+
+        if strayLightData is None:
+            raise RuntimeError("No strayLightData supplied for correction.")
+
         exposureMetadata = exposure.getMetadata()
         detId = exposure.getDetector().getId()
-
         if self.config.doRotatorAngleCorrection:
             angleStart, angleEnd = inrStartEnd(exposure.getInfo().getVisitInfo())
             self.log.debug(
@@ -101,7 +114,7 @@ def run(self, exposure, strayLightData):
             angleStart = exposureMetadata.getDouble('INR-STR')
             angleEnd = None
 
-        self.log.info("Correcting y-band background")
+        self.log.info("Correcting y-band background.")
 
         model = strayLightData.evaluate(angleStart*degrees,
                                         None if angleStart == angleEnd else angleEnd*degrees)