DatasetType

class lsst.daf.butler.DatasetType(name: str, dimensions: Union[DimensionGraph, Iterable[Dimension]], storageClass: Union[StorageClass, str], parentStorageClass: Optional[Union[StorageClass, str]] = None, *, universe: Optional[DimensionUniverse] = None, isCalibration: bool = False)

Bases: object

A named category of Datasets.

Defines how they are organized, related, and stored.

A concrete, final class whose instances represent DatasetTypes. DatasetType instances may be constructed without a Registry, but they must be registered via Registry.registerDatasetType() before corresponding Datasets may be added. DatasetType instances are immutable.

Parameters:

name : str

A string name for the Dataset; must correspond to the same DatasetType across all Registries. Names must start with an upper or lowercase letter, and may contain only letters, numbers, and underscores. Component dataset types should contain a single period separating the base dataset type name from the component name (and may be recursive).

dimensions : DimensionGraph or iterable of Dimension

Dimensions used to label and relate instances of this DatasetType. If not a DimensionGraph, universe must be provided as well.

storageClass : StorageClass or str

Instance of a StorageClass or name of StorageClass that defines how this DatasetType is persisted.

parentStorageClass : StorageClass or str, optional

Instance of a StorageClass or name of StorageClass that defines how the composite parent is persisted. Must be None if this is not a component. Mandatory if it is a component but can be the special temporary placeholder (DatasetType.PlaceholderParentStorageClass) to allow construction with an intent to finalize later.

universe : DimensionUniverse, optional

Set of all known dimensions, used to normalize dimensions if it is not already a DimensionGraph.

isCalibration : bool, optional

If True, this dataset type may be included in CALIBRATION collections.

Attributes Summary

PlaceholderParentStorageClass	Placeholder StorageClass that can be used temporarily for a component.
VALID_NAME_REGEX
dimensions	Return the Dimensions fir this dataset type.
name	Return a string name for the Dataset.
parentStorageClass	Return the storage class of the composite containing this component.
storageClass	Return StorageClass instance associated with this dataset type.

Methods Summary

component()	Return the component name (if defined).
componentTypeName(component)	Derive a component dataset type from a composite.
finalizeParentStorageClass(newParent)	Finalize the parent storage class definition.
from_json(json_str, universe, registry)	Return new class from JSON string.
from_simple(simple, str], universe, registry)	Construct a new object from the simplified form.
isCalibration()	Return if datasets of this type can be in calibration collections.
isComponent()	Return whether this DatasetType refers to a component.
isComposite()	Return whether this DatasetType is a composite.
makeAllComponentDatasetTypes()	Return all component dataset types for this composite.
makeComponentDatasetType(component)	Return a component dataset type from a composite.
makeCompositeDatasetType()	Return a composite dataset type from the component.
nameAndComponent()	Return the root name of this dataset type and any component.
nameWithComponent(datasetTypeName, componentName)	Form a valid DatasetTypeName from a parent and component.
splitDatasetTypeName(datasetTypeName)	Return the root name and the component from a composite name.
to_json(minimal)	Convert this class to JSON form.
to_simple(minimal)	Convert this class to a simple python type.

Attributes Documentation

PlaceholderParentStorageClass = StorageClass('PlaceHolder')

Placeholder StorageClass that can be used temporarily for a component.

This can be useful in pipeline construction where we are creating dataset types without a registry.

VALID_NAME_REGEX = re.compile('^[a-zA-Z][a-zA-Z0-9_]*(\\.[a-zA-Z][a-zA-Z0-9_]*)*$')

dimensions

Return the Dimensions fir this dataset type.

The dimensions label and relate instances of this DatasetType (DimensionGraph).

name

Return a string name for the Dataset.

Mmust correspond to the same DatasetType across all Registries.

parentStorageClass

Return the storage class of the composite containing this component.

Note that if DatasetType was constructed with a name of a StorageClass then Butler has to be initialized before using this property. Can be None if this is not a component of a composite. Must be defined if this is a component.

storageClass

Return StorageClass instance associated with this dataset type.

The StorageClass defines how this DatasetType is persisted. Note that if DatasetType was constructed with a name of a StorageClass then Butler has to be initialized before using this property.

Methods Documentation

component() → Optional[str]

Return the component name (if defined).

Returns:

comp : str

Name of component part of DatasetType name. None if this DatasetType is not associated with a component.

componentTypeName(component: str) → str

Derive a component dataset type from a composite.

Parameters:

component : str

Name of component

Returns:

derived : str

Compound name of this DatasetType and the component.

Raises:

KeyError

Requested component is not supported by this DatasetType.

finalizeParentStorageClass(newParent: lsst.daf.butler.core.storageClass.StorageClass) → None

Finalize the parent storage class definition.

Replaces the current placeholder parent storage class with the real parent.

Parameters:

newParent : StorageClass

The new parent to be associated with this composite dataset type. This replaces the temporary placeholder parent that was specified during construction.

Raises:

ValueError

Raised if this dataset type is not a component of a composite. Raised if a StorageClass is not given. Raised if the parent currently associated with the dataset type is not a placeholder.

classmethod from_json(json_str: str, universe: Optional[DimensionUniverse] = None, registry: Optional[Registry] = None) → SupportsSimple

Return new class from JSON string.

Converts a JSON string created by to_json and return something of the supplied class.

Parameters:

json_str : str

Representation of the dimensions in JSON format as created by to_json().

universe : DimensionUniverse, optional

The special graph of all known dimensions. Passed directly to from_simple().

registry : lsst.daf.butler.Registry, optional

Registry to use to convert simple name of a DatasetType to a full DatasetType. Passed directly to from_simple().

Returns:

constructed : Any

Newly-constructed object.

classmethod from_simple(simple: Union[Dict, str], universe: Optional[DimensionUniverse] = None, registry: Optional[Registry] = None) → DatasetType

Construct a new object from the simplified form.

This is usally data returned from the to_simple method.

Parameters:

simple : dict of [str, Any] or str

The value returned by to_simple().

universe : DimensionUniverse

The special graph of all known dimensions of which this graph will be a subset. Can be None if a registry is provided.

registry : lsst.daf.butler.Registry, optional

Registry to use to convert simple name of a DatasetType to a full DatasetType. Can be None if a full description of the type is provided along with a universe.

Returns:

datasetType : DatasetType

Newly-constructed object.

isCalibration() → bool

Return if datasets of this type can be in calibration collections.

Returns:

flag : bool

True if datasets of this type may be included in calibration collections.

isComponent() → bool

Return whether this DatasetType refers to a component.

Returns:

isComponent : bool

True if this DatasetType is a component, False otherwise.

isComposite() → bool

Return whether this DatasetType is a composite.

Returns:

isComposite : bool

True if this DatasetType is a composite type, False otherwise.

makeAllComponentDatasetTypes() → List[lsst.daf.butler.core.datasets.type.DatasetType]

Return all component dataset types for this composite.

Returns:

all : list of DatasetType

All the component dataset types. If this is not a composite then returns an empty list.

makeComponentDatasetType(component: str) → lsst.daf.butler.core.datasets.type.DatasetType

Return a component dataset type from a composite.

Assumes the same dimensions as the parent.

Parameters:

component : str

Name of component

Returns:

datasetType : DatasetType

A new DatasetType instance.

makeCompositeDatasetType() → lsst.daf.butler.core.datasets.type.DatasetType

Return a composite dataset type from the component.

Returns:

composite : DatasetType

The composite dataset type.

Raises:

RuntimeError

Raised if this dataset type is not a component dataset type.

nameAndComponent() → Tuple[str, Optional[str]]

Return the root name of this dataset type and any component.

Returns:

rootName : str

Root name for this DatasetType without any components.

componentName : str

The component if it has been specified, else None.

static nameWithComponent(datasetTypeName: str, componentName: str) → str

Form a valid DatasetTypeName from a parent and component.

No validation is performed.

Parameters:

datasetTypeName : str

Base type name.

componentName : str

Name of component.

Returns:

compTypeName : str

Name to use for component DatasetType.

static splitDatasetTypeName(datasetTypeName: str) → Tuple[str, Optional[str]]

Return the root name and the component from a composite name.

Parameters:

datasetTypeName : str

The name of the dataset type, can include a component using a “.”-separator.

Returns:

rootName : str

Root name without any components.

componentName : str

The component if it has been specified, else None.

Notes

If the dataset type name is a.b.c this method will return a root name of a and a component name of b.c.

to_json(minimal: bool = False) → str

Convert this class to JSON form.

The class type is not recorded in the JSON so the JSON decoder must know which class is represented.

Parameters:

minimal : bool, optional

Use minimal serialization. Requires Registry to convert back to a full type.

Returns:

json : str

The class in JSON string format.

to_simple(minimal: bool = False) → Union[Dict[KT, VT], str]

Convert this class to a simple python type.

This makes it suitable for serialization.

Parameters:

minimal : bool, optional

Use minimal serialization. Requires Registry to convert back to a full type.

Returns:

simple : dict or str

The object converted to a dictionary or a simple string.