Merge pull request #312 from sot/better-dark-date

Pickle dark_date always and use it if existing for selecting dark map

proseco/catalog.py

@@ -180,7 +180,6 @@ class ACATable(ACACatalogTable):
     optimize = MetaAttribute(default=True)
     call_args = MetaAttribute(default={})
     version = MetaAttribute()
-    dark_date = MetaAttribute()
 
     # For validation with get_aca_catalog(obsid), store the starcheck
     # catalog in the ACATable meta.

proseco/core.py

@@ -4,6 +4,7 @@
 import pickle
 import inspect
 import time
+import warnings
 from copy import copy
 from pathlib import Path
 
@@ -540,6 +541,7 @@ class ACACatalogTable(BaseCatalogTable):
     t_ccd_acq = MetaAttribute()
     t_ccd_guide = MetaAttribute()
     date = MetaAttribute()
+    dark_date = MetaAttribute()
     dither_acq = MetaAttribute()
     dither_guide = MetaAttribute()
     detector = MetaAttribute()
@@ -561,16 +563,35 @@ def dark(self):
         if hasattr(self, '_dark'):
             return self._dark
 
+        # If self.dark_date is already set (most likely after unpickling an existing
+        # catalog), then use that instead of the observation date for getting the dark map.
+        if self.dark_date:
+            dark_id = get_dark_cal_id(date=self.dark_date, select='nearest')
+            self.log(f'Found dark cal image {dark_id} nearest self.dark_date={self.dark_date}')
+
+            # Warn if the pickled dark_date is not the same as we would have gotten based
+            # on the observation date.
+            dark_id_for_date = get_dark_cal_id(date=self.date, select='before')
+            if dark_id != dark_id_for_date:
+                warnings.warn(f'Unexpected dark_date: '
+                              f'dark_id nearest dark_date={self.dark_date} is {dark_id} '
+                              f'but dark_id before obs date={self.date} is {dark_id_for_date}')
+        else:
+            dark_id = get_dark_cal_id(date=self.date, select='before')
+            self.log(f'Found dark cal image {dark_id} before self.date={self.date}')
+
+        # In all cases set self.dark_date to be the actual date of the dark cal
+        # we are using, not what might have been set on input.
+        self.dark_date = dark_id[:4] + ':' + dark_id[4:]
+
         # Dark current map handling.  If asking for `dark` attribute without having set
         # it then auto-fetch from mica.  Note that get_dark_cal_image caches returned values
         # using LRU cache on all params, so this is efficient for the different
         # catalog tables.
-        self.log(f'Getting dark cal image at date={self.date} t_ccd={self.t_ccd:.1f}')
-        self.dark = get_dark_cal_image(date=self.date, select='before',
+        self.log(f'Getting dark cal image at date={self.dark_date} t_ccd={self.t_ccd:.1f} ')
+        self.dark = get_dark_cal_image(date=self.dark_date, select='nearest',
                                        t_ccd_ref=self.t_ccd,
                                        aca_image=False)
-        dark_id = get_dark_cal_id(date=self.date, select='before')
-        self.dark_date = dark_id[:4] + ':' + dark_id[4:]
 
         return self._dark
 

proseco/tests/test_catalog.py

@@ -760,3 +760,17 @@ def test_includes_for_obsid():
 
     out = includes_for_obsid(8008)
     assert out == exp
+
+
+def test_dark_date_warning():
+    aca = get_aca_catalog(**STD_INFO)
+    acap = pickle.loads(pickle.dumps(aca))
+    assert acap.dark_date == '2017:272'
+
+    # Fudge date forward, after the 2018:002 dark cal
+    acap.date = '2018:010'
+    with pytest.warns(None) as warns:
+        acap.dark  # Accessing the `dark` property triggers code to read it (and warn)
+
+    assert len(warns) == 1
+    assert 'Unexpected dark_date: dark_id nearest dark_date' in str(warns[0].message)