FileFormatter

class lsst.daf.butler.formatters.fileFormatter.FileFormatter(fileDescriptor)

Bases: lsst.daf.butler.Formatter

Interface for reading and writing files on a POSIX file system.

Attributes Summary

extension	Default file extension to use for writing files.
fileDescriptor	FileDescriptor associated with this formatter (Formatter, read-only)
unsupportedParameters

Methods Summary

name()	Returns the fully qualified name of the formatter.
predictPath()	Return the path that would be returned by write, without actually writing.
predictPathFromLocation(location)	Return the path that would be returned by write, without actually writing.
read([component])	Read data from a file.
segregateParameters([parameters])	Segregate the supplied parameters into those understood by the formatter and those not understood by the formatter.
write(inMemoryDataset)	Write a Python object to a file.

Attributes Documentation

extension = None

Default file extension to use for writing files. None means that no modifications will be made to the supplied file extension. (str)

fileDescriptor

FileDescriptor associated with this formatter (Formatter, read-only)

unsupportedParameters = frozenset()

Methods Documentation

classmethod name()

Returns the fully qualified name of the formatter.

Returns:

name : str

Fully-qualified name of formatter class.

predictPath()

Return the path that would be returned by write, without actually writing.

Uses the FileDescriptor associated with the instance.

Returns:

path : str

Path within datastore that would be associated with the location stored in this Formatter.

classmethod predictPathFromLocation(location)

Return the path that would be returned by write, without actually writing.

Parameters:

location : Location

Location of file for which path prediction is required.

Returns:

path : str

Path within datastore that would be associated with this location.

read(component=None)

Read data from a file.

Parameters:

component : str, optional

Component to read from the file. Only used if the StorageClass for reading differed from the StorageClass used to write the file.

Returns:

inMemoryDataset : object

The requested data as a Python object. The type of object is controlled by the specific formatter.

Raises:

ValueError

Component requested but this file does not seem to be a concrete composite.

segregateParameters(parameters=None)

Segregate the supplied parameters into those understood by the formatter and those not understood by the formatter.

Any unsupported parameters are assumed to be usable by associated assemblers.

Parameters:

parameters : dict, optional

Parameters with values that have been supplied by the caller and which might be relevant for the formatter. If None parameters will be read from the registered FileDescriptor.

Returns:

supported : dict

Those parameters supported by this formatter.

unsupported : dict

Those parameters not supported by this formatter.

write(inMemoryDataset)

Write a Python object to a file.

Parameters:

inMemoryDataset : object

The Python object to store.

Returns:

path : str

The path where the primary file is stored within the datastore.