Add limited option for Registries.

Registries configured with limited=True do not have any DataUnit
metadata or join tables (or the foreign keys from Dataset to those
tables).  That disables a few operations, but makes it unnecessary
to populate those tables just to do simple get and put Butler
operations.

config/registry.yaml

@@ -2,6 +2,7 @@
 registry:
   cls: lsst.daf.butler.registries.sqliteRegistry.SqliteRegistry
   db: 'sqlite:///:memory:'
+  limited: false
   skypix:
     cls: lsst.sphgeom.HtmPixelization
     level: 7

config/schema.yaml

@@ -97,44 +97,51 @@ schema:
       -
         src: camera
         tgt: Camera.camera
+        limited: false
       -
         src:
           - camera
           - physical_filter
         tgt:
           - PhysicalFilter.camera
           - PhysicalFilter.physical_filter
+        limited: false
       -
         src:
           - camera
           - sensor
         tgt:
           - Sensor.camera
           - Sensor.sensor
+        limited: false
       -
         src:
           - camera
           - visit
         tgt:
           - Visit.camera
           - Visit.visit
+        limited: false
       -
         src:
           - camera
           - exposure
         tgt:
           - Exposure.camera
           - Exposure.exposure
+        limited: false
       -
         src: skymap
         tgt: Skymap.skymap
+        limited: false
       -
         src:
           - skymap
           - tract
         tgt:
           - Tract.skymap
           - Tract.tract
+        limited: false
       -
         src:
           - skymap
@@ -144,6 +151,7 @@ schema:
           - Patch.skymap
           - Patch.tract
           - Patch.patch
+        limited: false
 
     DatasetComposition:
       doc: >
@@ -440,6 +448,7 @@ schema:
     Camera:
       doc: >
         A definition table containing recognized Camera values.
+      limited: false
       columns:
       -
         name: camera
@@ -452,6 +461,7 @@ schema:
       doc: >
         A view aggregating all distinct AbstractFilters references by any
         PhysicalFilter.
+      limited: false
       columns:
       -
         name: abstract_filter
@@ -467,6 +477,7 @@ schema:
       doc: >
         A Camera-populated table that relates a PhysicalFilter
         to its Camera and optional AbstractFilter.
+      limited: false
       columns:
       -
         name: camera
@@ -495,6 +506,7 @@ schema:
       doc: >
         A Camera-populated table that relates a Sensor to its Camera and
         provides additional labels.
+      limited: false
       columns:
       -
         name: camera
@@ -536,6 +548,7 @@ schema:
     Visit:
       doc: >
         A table containing Camera-generic metadata for a Visit.
+      limited: false
       columns:
       -
         name: camera
@@ -663,6 +676,7 @@ schema:
     Exposure:
       doc: >
         A table containing Camera-generic Exposure metadata.
+      limited: false
       columns:
       -
         name: camera
@@ -751,6 +765,7 @@ schema:
       doc: >
         A table containing registered SkyMaps and the the SHA1 hashes
         used to compare them.
+      limited: false
       columns:
       -
         name: skymap
@@ -773,6 +788,7 @@ schema:
       doc: >
         A SkyMap-populated table relating a Tract to its spatial region
         on the sky.
+      limited: false
       columns:
       -
         name: skymap
@@ -808,6 +824,7 @@ schema:
       doc: >
         A table relating a Patch to its position within a Tract and
         on the sky.
+      limited: false
       columns:
       -
         name: skymap
@@ -872,6 +889,7 @@ schema:
         expected to be calculated outside the database and added/updated
         whenever the Visit's region is.  This table contains exactly one
         entry for each Visit+Sensor combination.
+      limited: false
       columns:
       -
         name: camera
@@ -920,6 +938,7 @@ schema:
         - Sensor.sensor
 
     MultiCameraExposureJoin:
+      limited: false
       columns:
       -
         name: camera_1
@@ -958,6 +977,7 @@ schema:
           - Exposure.exposure
 
     VisitSensorSkyPixJoin:
+      limited: false
       columns:
       -
         name: camera
@@ -991,6 +1011,7 @@ schema:
           - VisitSensorRegion.sensor
 
     VisitSkyPixJoin:
+      limited: false
       columns:
       -
         name: camera
@@ -1020,6 +1041,7 @@ schema:
         FROM VisitSensorSkyPixJoin;
 
     PatchSkyPixJoin:
+      limited: false
       columns:
       -
         name: skymap
@@ -1053,6 +1075,7 @@ schema:
           - Patch.patch
 
     TractSkyPixJoin:
+      limited: false
       columns:
       -
         name: skymap
@@ -1082,6 +1105,7 @@ schema:
         FROM PatchSkyPixJoin;
 
     VisitSensorPatchJoin:
+      limited: false
       columns:
       -
         name: camera
@@ -1146,6 +1170,7 @@ schema:
           );
 
     VisitPatchJoin:
+      limited: false
       columns:
       -
         name: camera
@@ -1202,6 +1227,7 @@ schema:
           );
 
     VisitSensorTractJoin:
+      limited: false
       columns:
       -
         name: camera
@@ -1258,6 +1284,7 @@ schema:
           );
 
     VisitTractJoin:
+      limited: false
       columns:
       -
         name: camera

python/lsst/daf/butler/core/registry.py

@@ -21,14 +21,29 @@
 
 from abc import ABCMeta, abstractmethod
 import contextlib
+import functools
 
 from .utils import doImport
 from .config import Config, ConfigSubset
 from .dataUnit import DataUnitConfig, DataUnitRegistry
 from .schema import SchemaConfig
 from .utils import transactional
 
-__all__ = ("RegistryConfig", "Registry")
+__all__ = ("RegistryConfig", "Registry", "disableWhenLimited")
+
+
+def disableWhenLimited(func):
+    """Decorator that indicates that a method should raise NotImplementedError
+    on Registries whose ``limited`` attribute is ``True``.
+
+    This implements that check and raise for all subclasses.
+    """
+    @functools.wraps(func)
+    def inner(self, *args, **kwargs):
+        if self.limited:
+            raise NotImplementedError("Not implemented for limited Registry.")
+        return func(self, *args, **kwargs)
+    return inner
 
 
 class RegistryConfig(ConfigSubset):
@@ -143,6 +158,12 @@ def __init__(self, registryConfig, schemaConfig=None, dataUnitConfig=None, creat
     def __str__(self):
         return "None"
 
+    @property
+    def limited(self):
+        """If True, this Registry does not maintain DataUnit metadata or
+        relationships (`bool`)."""
+        return self.config.get("limited", False)
+
     @contextlib.contextmanager
     def transaction(self):
         """Optionally implemented in `Registry` subclasses to provide exception
@@ -168,7 +189,12 @@ def transaction(self):
 
     @property
     def pixelization(self):
-        """Object that interprets SkyPix DataUnit values (`sphgeom.Pixelization`)."""
+        """Object that interprets SkyPix DataUnit values (`sphgeom.Pixelization`).
+
+        ``None`` for limited registries.
+        """
+        if self.limited:
+            return None
         if self._pixelization is None:
             pixelizationCls = doImport(self.config["skypix", "cls"])
             self._pixelization = pixelizationCls(level=self.config["skypix", "level"])
@@ -625,6 +651,7 @@ def markInputUsed(self, quantum, ref):
         raise NotImplementedError("Must be implemented by subclass")
 
     @abstractmethod
+    @disableWhenLimited
     @transactional
     def addDataUnitEntry(self, dataUnitName, values):
         """Add a new `DataUnit` entry.
@@ -648,10 +675,13 @@ def addDataUnitEntry(self, dataUnitName, values):
         ValueError
             If an entry with the primary-key defined in `values` is already
             present.
+        NotImplementedError
+            If ``self.limited`` is ``True``.
         """
         raise NotImplementedError("Must be implemented by subclass")
 
     @abstractmethod
+    @disableWhenLimited
     def findDataUnitEntry(self, dataUnitName, value):
         """Return a `DataUnit` entry corresponding to a `value`.
 
@@ -667,10 +697,13 @@ def findDataUnitEntry(self, dataUnitName, value):
         dataUnitEntry : `dict`
             Dictionary with all `DataUnit` values, or `None` if no matching
             entry is found.
+        NotImplementedError
+            If ``self.limited`` is ``True``.
         """
         raise NotImplementedError("Must be implemented by subclass")
 
     @abstractmethod
+    @disableWhenLimited
     @transactional
     def setDataUnitRegion(self, dataUnitNames, value, region, update=True):
         """Set the region field for a DataUnit instance or a combination
@@ -689,10 +722,16 @@ def setDataUnitRegion(self, dataUnitNames, value, region, update=True):
             If True, existing region information for these DataUnits is being
             replaced.  This is usually required because DataUnit entries are
             assumed to be pre-inserted prior to calling this function.
+
+        Raises
+        ------
+        NotImplementedError
+            If ``self.limited`` is ``True``.
         """
         raise NotImplementedError("Must be implemented by subclass")
 
     @abstractmethod
+    @disableWhenLimited
     def getRegion(self, dataId):
         """Get region associated with a dataId.
 
@@ -712,10 +751,13 @@ def getRegion(self, dataId):
         KeyError
             If the set of dataunits for the ``dataId`` does not correspond to
             a unique spatial lookup.
+        NotImplementedError
+            If ``self.limited`` is ``True``.
         """
         raise NotImplementedError("Must be implemented by subclass")
 
     @abstractmethod
+    @disableWhenLimited
     def selectDataUnits(self, originInfo, expression, neededDatasetTypes, futureDatasetTypes):
         """Evaluate a filter expression and lists of
         `DatasetTypes <DatasetType>` and return a set of data unit values.
@@ -746,5 +788,10 @@ def selectDataUnits(self, originInfo, expression, neededDatasetTypes, futureData
         ------
         row : `PreFlightUnitsRow`
             Single row is a unique combination of units in a transform.
+
+        Raises
+        ------
+        NotImplementedError
+            If ``self.limited`` is ``True``.
         """
         raise NotImplementedError("Must be implemented by subclass")