DM-43027: Make RemoteButler.find_dataset consistent with DirectButler

python/lsst/daf/butler/_timespan.py

@@ -26,16 +26,20 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 from __future__ import annotations
 
-__all__ = ("Timespan",)
+__all__ = (
+    "SerializedTimespan",
+    "Timespan",
+)
 
 import enum
 import warnings
 from collections.abc import Generator
-from typing import TYPE_CHECKING, Any, ClassVar, Union
+from typing import TYPE_CHECKING, Annotated, Any, ClassVar, Union
 
 import astropy.time
 import astropy.utils.exceptions
 import yaml
+from pydantic import Field
 
 # As of astropy 4.2, the erfa interface is shipped independently and
 # ErfaWarning is no longer an AstropyWarning
@@ -69,6 +73,11 @@ class _SpecialTimespanBound(enum.Enum):
 
 TimespanBound = Union[astropy.time.Time, _SpecialTimespanBound, None]
 
+SerializedTimespan = Annotated[list[int], Field(min_length=2, max_length=2)]
+"""JSON-serializable representation of the Timespan class, as a list of two
+integers ``[begin, end]`` in nanoseconds since the epoch.
+"""
+
 
 class Timespan:
     """A half-open time interval with nanosecond precision.
@@ -483,7 +492,7 @@ def difference(self, other: Timespan) -> Generator[Timespan, None, None]:
             if intersection._nsec[1] < self._nsec[1]:
                 yield Timespan(None, None, _nsec=(intersection._nsec[1], self._nsec[1]))
 
-    def to_simple(self, minimal: bool = False) -> list[int]:
+    def to_simple(self, minimal: bool = False) -> SerializedTimespan:
         """Return simple python type form suitable for serialization.
 
         Parameters
@@ -502,7 +511,7 @@ def to_simple(self, minimal: bool = False) -> list[int]:
     @classmethod
     def from_simple(
         cls,
-        simple: list[int] | None,
+        simple: SerializedTimespan | None,
         universe: DimensionUniverse | None = None,
         registry: Registry | None = None,
     ) -> Timespan | None:

python/lsst/daf/butler/datastores/fileDatastoreClient.py

@@ -3,7 +3,7 @@
 from typing import Any, Literal
 
 import pydantic
-from lsst.daf.butler import DatasetRef, Location, StorageClass
+from lsst.daf.butler import DatasetRef, Location
 from lsst.daf.butler.datastore.cache_manager import DatastoreDisabledCacheManager
 from lsst.daf.butler.datastore.stored_file_info import SerializedStoredFileInfo, StoredFileInfo
 from lsst.daf.butler.datastores.file_datastore.get import (
@@ -47,8 +47,6 @@ def get_dataset_as_python_object(
     payload: FileDatastoreGetPayload,
     *,
     parameters: Mapping[str, Any] | None,
-    storageClass: StorageClass | str | None,
-    component: str | None,
 ) -> Any:
     """Retrieve an artifact from storage and return it as a Python object.
 
@@ -62,12 +60,6 @@ def get_dataset_as_python_object(
     parameters : `Mapping`[`str`, `typing.Any`]
         `StorageClass` and `Formatter` parameters to be used when converting
         the artifact to a Python object.
-    storageClass : `StorageClass` | `str` | `None`
-        Overrides the `StorageClass` to be used when converting the artifact to
-        a Python object.  If `None`, uses the `StorageClass` specified by
-        ``payload``.
-    component : `str` | `None`
-        Selects which component of the artifact to retrieve.
 
     Returns
     -------
@@ -79,14 +71,6 @@ def get_dataset_as_python_object(
         for file_info in payload.file_info
     ]
 
-    # If we have both a component override and a storage class override, the
-    # component override has to be applied first.  DatasetRef cares because it
-    # is checking compatibility of the storage class with its DatasetType.
-    if component is not None:
-        ref = ref.makeComponentRef(component)
-    if storageClass is not None:
-        ref = ref.overrideStorageClass(storageClass)
-
     datastore_file_info = generate_datastore_get_information(
         fileLocations,
         ref=ref,

python/lsst/daf/butler/remote_butler/_collection_args.py

@@ -0,0 +1,76 @@
+# This file is part of daf_butler.
+#
+# Developed for the LSST Data Management System.
+# This product includes software developed by the LSST Project
+# (http://www.lsst.org).
+# See the COPYRIGHT file at the top-level directory of this distribution
+# for details of code ownership.
+#
+# This software is dual licensed under the GNU General Public License and also
+# under a 3-clause BSD license. Recipients may choose which of these licenses
+# to use; please see the files gpl-3.0.txt and/or bsd_license.txt,
+# respectively.  If you choose the GPL option then the following text applies
+# (but note that there is still no warranty even if you opt for BSD instead):
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from __future__ import annotations
+
+import re
+from typing import cast
+
+from ..registry import CollectionArgType
+from ..registry.wildcards import CollectionWildcard
+from .server_models import CollectionList
+
+
+def convert_collection_arg_to_glob_string_list(arg: CollectionArgType) -> CollectionList:
+    """Convert the collections argument used by many Butler/registry methods to
+    a format suitable for sending to Butler server.
+
+    Parameters
+    ----------
+    arg : `CollectionArgType`
+        Collection search pattern in many possible formats.
+
+    Returns
+    -------
+    glob_list : `CollectionList`
+        Collection search patterns normalized to a list of globs string.
+
+    Raises
+    ------
+    TypeError
+        If the search pattern provided by the user cannot be converted to a
+        glob string.
+    """
+    if arg is ...:
+        return CollectionList(["*"])
+    elif isinstance(arg, str):
+        return CollectionList([arg])
+    elif isinstance(arg, re.Pattern):
+        raise TypeError("RemoteButler does not support regular expressions as search patterns")
+    elif isinstance(arg, CollectionWildcard):
+        # In theory this could work, but CollectionWildcard eagerly converts
+        # any glob strings to regexes.  So it would need some rework to
+        # preserve the original string inputs.  CollectionWildcard has likely
+        # never been used in the wild by an end-user so this probably isn't
+        # worth figuring out.
+        raise TypeError("RemoteButler does not accept CollectionWildcard instances as search patterns")
+    else:
+        search = list(arg)
+        for item in search:
+            if not isinstance(item, str):
+                raise TypeError("RemoteButler only accepts strings and lists of strings as search patterns")
+        return CollectionList(cast(list[str], search))

python/lsst/daf/butler/remote_butler/_registry.py

@@ -47,9 +47,17 @@
     DimensionRecord,
     DimensionUniverse,
 )
-from ..registry import CollectionArgType, CollectionSummary, CollectionType, Registry, RegistryDefaults
+from ..registry import (
+    CollectionArgType,
+    CollectionSummary,
+    CollectionType,
+    DatasetTypeError,
+    Registry,
+    RegistryDefaults,
+)
 from ..registry.queries import DataCoordinateQueryResults, DatasetQueryResults, DimensionRecordQueryResults
 from ..remote_butler import RemoteButler
+from ._collection_args import convert_collection_arg_to_glob_string_list
 
 
 class RemoteButlerRegistry(Registry):
@@ -146,10 +154,29 @@
         datastore_records: bool = False,
         **kwargs: Any,
     ) -> DatasetRef | None:
-        # There is an implementation of find_dataset on RemoteButler, but the
-        # definition of the collections parameter is incompatible and timespans
-        # aren't supported yet.
-        raise NotImplementedError()
+        # Components are supported by Butler.find_dataset, but are required to
+        # raise an exception in registry.findDataset (see
+        # RegistryTests.testComponentLookups).  Apparently the registry version
+        # used to support components, but at some point a decision was made to
+        # draw a hard architectural boundary between registry and datastore so
+        # that registry is no longer allowed to know about components.
+        if _is_component_dataset_type(datasetType):
+            raise DatasetTypeError(
+                "Component dataset types are not supported;"
+                " use DatasetRef or DatasetType methods to obtain components from parents instead."
+            )
+
+        if collections is not None:
+            collections = convert_collection_arg_to_glob_string_list(collections)
+
+        return self._butler.find_dataset(
+            datasetType,
+            dataId,
+            collections=collections,
+            timespan=timespan,
+            datastore_records=datastore_records,
+            **kwargs,
+        )
 
     def insertDatasets(
         self,
@@ -310,3 +337,14 @@
     @storageClasses.setter
     def storageClasses(self, value: StorageClassFactory) -> None:
         raise NotImplementedError()
+
+
+def _is_component_dataset_type(dataset_type: DatasetType | str) -> bool:
+    """Return true if the given dataset type refers to a component."""
+    if isinstance(dataset_type, DatasetType):
+        return dataset_type.component() is not None
+    elif isinstance(dataset_type, str):
+        parent, component = DatasetType.splitDatasetTypeName(dataset_type)
+        return component is not None
+    else:
+        raise TypeError(f"Expected DatasetType or str, got {dataset_type!r}")