DatastoreCacheManager

class lsst.daf.butler.DatastoreCacheManager(config: Union[str, DatastoreCacheManagerConfig], universe: DimensionUniverse)

Bases: lsst.daf.butler.AbstractDatastoreCacheManager

A class for managing caching in a Datastore using local files.

Parameters

configstr or DatastoreCacheManagerConfig

Configuration to control caching.

universeDimensionUniverse

Set of all known dimensions, used to expand and validate any used in lookup keys.

Methods Summary

find_in_cache(ref, extension)	Look for a dataset in the cache and return its location.
move_to_cache(uri, ref)	Move a file to the cache.
should_be_cached(entity)	Indicate whether the entity should be added to the cache.

Methods Documentation

find_in_cache(ref: DatasetRef, extension: str) → Optional[ButlerURI]

Look for a dataset in the cache and return its location.

Parameters

refDatasetRef

Dataset to locate in the cache.

extensionstr

File extension expected.

Returns

uriButlerURI or None

The URI to the cached file, or None if the file has not been cached.

move_to_cache(uri: ButlerURI, ref: DatasetRef) → Optional[ButlerURI]

Move a file to the cache.

Move the given file into the cache, using the supplied DatasetRef for naming. A call is made to should_be_cached() and if the DatasetRef should not be accepted None will be returned.

Parameters

uriButlerURI

Location of the file to be relocated to the cache. Will be moved.

refDatasetRef

Ref associated with this file. Will be used to determine the name of the file within the cache.

Returns

newButlerURI or None

URI to the file within the cache, or None if the dataset was not accepted by the cache.

should_be_cached(entity: Union[DatasetRef, DatasetType, StorageClass]) → bool

Indicate whether the entity should be added to the cache.

This is relevant when reading or writing.

Parameters

entityStorageClass or DatasetType or DatasetRef

Thing to test against the configuration. The name property is used to determine a match. A DatasetType will first check its name, before checking its StorageClass. If there are no matches the default will be returned.

Returns

should_cachebool

Returns True if the dataset should be cached; False otherwise.