Constraints¶

class lsst.daf.butler.Constraints(config, universe=None)¶

Determine whether a DatasetRef, DatasetType, or StorageClass is allowed to be handled.

Parameters:	config : `ConstraintsConfig` or `str` Load configuration. If `None` then this is equivalent to having no restrictions. universe : `DimensionUniverse`, optional The set of all known dimensions. If not `None`, any look up keys involving dimensions will be normalized. Normalization only happens once.

Attributes Summary

matchAllKey Configuration key associated with matching everything.

Methods Summary

`getLookupKeys`()	Retrieve the look up keys for all the constraints entries.
`isAcceptable`(entity)	Check whether the supplied entity will be acceptable to whatever this `Constraints` class is associated with.
`normalizeDimensions`(universe)	Normalize consraint lookups that use dimensions.

Attributes Documentation

matchAllKey = LookupKey(name='all',)¶: Configuration key associated with matching everything.

Methods Documentation

getLookupKeys()¶

Retrieve the look up keys for all the constraints entries.

Returns:	keys : `set` of `LookupKey` The keys available for determining constraints. Does not include the special “all” lookup key.

isAcceptable(entity)¶

Check whether the supplied entity will be acceptable to whatever this Constraints class is associated with.

Parameters:	entity : `DatasetType`, `DatasetRef`, or `StorageClass` Instance to use to look in constraints table. The entity itself reports the `LookupKey` that is relevant.
Returns:	allowed : `bool` `True` if the entity is allowed.

normalizeDimensions(universe)¶

Normalize consraint lookups that use dimensions.

Parameters:	universe : `DimensionUniverse` The set of all known dimensions. If `None`, returns without action.
Raises:	ValueError Raised if a key exists where a dimension is not part of the `universe`.

Notes

Goes through all constraint lookups, and for keys that include dimensions, rewrites those keys to use a verified set of dimensions.

Returns without action if the keys have already been normalized.