Source code for jwst.datamodels.util

Various utility functions and data types

import sys
import warnings
import os
from os.path import basename
from platform import system as platform_system
import psutil
import traceback
import logging

import asdf

import numpy as np
from import fits
from stdatamodels import filetype
from stdatamodels import s3_utils
from stdatamodels.model_base import _FileReference

from ..lib.basic_utils import bytes2human

log = logging.getLogger(__name__)

class NoTypeWarning(Warning):

[docs]def open(init=None, memmap=False, **kwargs): """ Creates a DataModel from a number of different types Parameters ---------- init : shape tuple, file path, file object,, numpy array, dict, None - None: A default data model with no shape - shape tuple: Initialize with empty data of the given shape - file path: Initialize from the given file (FITS , JSON or ASDF) - readable file object: Initialize from the given file object - Initialize from the given `` - A numpy array: A new model with the data array initialized to what was passed in. - dict: The object model tree for the data model memmap : bool Turn memmap of FITS file on or off. (default: False). Ignored for ASDF files. kwargs : dict Additional keyword arguments passed to lower level functions. These arguments are generally file format-specific. Arguments of note are: - FITS skip_fits_update - bool or None `True` to skip updating the ASDF tree from the FITS headers, if possible. If `None`, value will be taken from the environmental SKIP_FITS_UPDATE. Otherwise, the default value is `True`. Returns ------- model : DataModel instance """ from . import model_base # Initialize variables used to select model class hdulist = {} shape = () file_name = None file_to_close = None # Get special cases for opening a model out of the way # all special cases return a model if they match if init is None: return model_base.JwstDataModel(None) elif isinstance(init, model_base.JwstDataModel): # Copy the object so it knows not to close here return init.__class__(init) elif isinstance(init, (str, bytes)) or hasattr(init, "read"): # If given a string, presume its a file path. # if it has a read method, assume a file descriptor if isinstance(init, bytes): init = init.decode(sys.getfilesystemencoding()) file_name = basename(init) file_type = filetype.check(init) if file_type == "fits": if s3_utils.is_s3_uri(init): hdulist = else: hdulist =, memmap=memmap) file_to_close = hdulist elif file_type == "asn": # Read the file as an association / model container from . import container return container.ModelContainer(init, **kwargs) elif file_type == "asdf": if s3_utils.is_s3_uri(init): asdffile =, **kwargs) else: asdffile =, **kwargs) # Detect model type, then get defined model, and call it. new_class = _class_from_model_type(asdffile) if new_class is None: # No model class found, so return generic DataModel. return model_base.JwstDataModel(asdffile, **kwargs) return new_class(asdffile) elif isinstance(init, tuple): for item in init: if not isinstance(item, int): raise ValueError("shape must be a tuple of ints") shape = init elif isinstance(init, np.ndarray): shape = init.shape elif isinstance(init, fits.HDUList): hdulist = init elif is_association(init) or isinstance(init, list): from . import container return container.ModelContainer(init, **kwargs) # If we have it, determine the shape from the science hdu if hdulist: # So we don't need to open the image twice init = hdulist info = init.fileinfo(0) if info is not None: file_name = info.get('filename') try: hdu = hdulist[('SCI', 1)] except (KeyError, NameError): shape = () else: if hasattr(hdu, 'shape'): shape = hdu.shape else: shape = () # First try to get the class name from the primary header new_class = _class_from_model_type(hdulist) has_model_type = new_class is not None # Special handling for ramp files for backwards compatibility if new_class is None: new_class = _class_from_ramp_type(hdulist, shape) # Or get the class from the reference file type and other header keywords if new_class is None: new_class = _class_from_reftype(hdulist, shape) # Or Get the class from the shape if new_class is None: new_class = _class_from_shape(hdulist, shape) # Throw an error if these attempts were unsuccessful if new_class is None: raise TypeError("Can't determine datamodel class from argument to open") # Log a message about how the model was opened if file_name: log.debug(f'Opening {file_name} as {new_class}') else: log.debug(f'Opening as {new_class}') # Actually open the model model = new_class(init, **kwargs) # Close the hdulist if we opened it if file_to_close is not None: # TODO: We need a better solution than messing with DataModel # internals. model._file_references.append(_FileReference(file_to_close)) if not has_model_type: class_name = new_class.__name__.split('.')[-1] if file_name: warnings.warn(f"model_type not found. Opening {file_name} as a {class_name}", NoTypeWarning) try: delattr(model.meta, 'model_type') except AttributeError: pass return model
def _class_from_model_type(init): """ Get the model type from the primary header, lookup to get class Parameter --------- init: AsdfFile or HDUList Return ------ new_class: str or None """ from . import _defined_models as defined_models if init: if isinstance(init, fits.hdu.hdulist.HDUList): primary = init[0] model_type = primary.header.get('DATAMODL') elif isinstance(init, asdf.AsdfFile): try: model_type = init.tree['meta']['model_type'] except KeyError: model_type = None if model_type is None: new_class = None else: new_class = defined_models.get(model_type) else: new_class = None return new_class def _class_from_ramp_type(hdulist, shape): """ Special check to see if file is ramp file """ if not hdulist: new_class = None else: if len(shape) == 4: try: hdulist['DQ'] except KeyError: from . import ramp new_class = ramp.RampModel else: new_class = None else: new_class = None return new_class def _class_from_reftype(hdulist, shape): """ Get the class name from the reftype and other header keywords """ if not hdulist: new_class = None else: primary = hdulist[0] reftype = primary.header.get('REFTYPE') if reftype is None: new_class = None else: from . import reference if len(shape) == 0: new_class = reference.ReferenceFileModel elif len(shape) == 2: new_class = reference.ReferenceImageModel elif len(shape) == 3: new_class = reference.ReferenceCubeModel elif len(shape) == 4: new_class = reference.ReferenceQuadModel else: new_class = None return new_class def _class_from_shape(hdulist, shape): """ Get the class name from the shape """ if len(shape) == 0: from . import model_base new_class = model_base.JwstDataModel elif len(shape) == 4: from . import quad new_class = quad.QuadModel elif len(shape) == 3: from . import cube new_class = cube.CubeModel elif len(shape) == 2: try: hdulist[('SCI', 2)] except (KeyError, NameError): # It's an ImageModel from . import image new_class = image.ImageModel else: # It's a MultiSlitModel from . import multislit new_class = multislit.MultiSlitModel else: new_class = None return new_class def can_broadcast(a, b): """ Given two shapes, returns True if they are broadcastable. """ for i in range(1, min(len(a), len(b)) + 1): adim = a[-i] bdim = b[-i] if not (adim == 1 or bdim == 1 or adim == bdim): return False return True def to_camelcase(token): return ''.join(x.capitalize() for x in token.split('_-')) def is_association(asn_data): """ Test if an object is an association by checking for required fields """ if isinstance(asn_data, dict): if 'asn_id' in asn_data and 'asn_pool' in asn_data: return True return False def check_memory_allocation(shape, allowed=None, model_type=None, include_swap=True): """Check if a DataModel can be instantiated Parameters ---------- shape : tuple The desired shape of the model. allowed : number or None Fraction of memory allowed to be allocated. If None, the environmental variable `DMODEL_ALLOWED_MEMORY` is retrieved. If undefined, then no check is performed. `1.0` would be all available memory. `0.5` would be half available memory. model_type : DataModel or None The desired model to instantiate. If None, `open` will be used to guess at a model type depending on shape. include_swap : bool Include available swap in the calculation. Returns ------- can_instantiate, required_memory : bool, number True if the model can be instantiated and the predicted memory footprint. """ # Determine desired allowed amount. if allowed is None: allowed = os.environ.get('DMODEL_ALLOWED_MEMORY', None) if allowed is not None: allowed = float(allowed) # Create the unit shape unit_shape = (1,) * len(shape) # Create the unit model. if model_type: unit_model = model_type(unit_shape) else: unit_model = open(unit_shape) # Size of the primary array. primary_array_name = unit_model.get_primary_array_name() primary_array = getattr(unit_model, primary_array_name) size = primary_array.nbytes for dimension in shape: size *= dimension # Get available memory available = get_available_memory(include_swap=include_swap) log.debug(f'Model size {bytes2human(size)} available system memory {bytes2human(available)}') if size > available: log.warning( f'Model {model_type} shape {shape} requires {bytes2human(size)} which is more than' f' system available {bytes2human(available)}' ) if allowed and size > (allowed * available): log.debug( f'Model size greater than allowed memory {bytes2human(allowed * available)}' ) return False, size return True, size def get_available_memory(include_swap=True): """Retrieve available memory Parameters ---------- include_swap : bool Include available swap in the calculation. Returns ------- available : number The amount available. """ system = platform_system() # Apple MacOS log.debug(f'Running OS is "{system}"') if system in ['Darwin']: return get_available_memory_darwin(include_swap=include_swap) # Default to Linux-like: return get_available_memory_linux(include_swap=include_swap) def get_available_memory_linux(include_swap=True): """Get memory for a Linux system Presume that the swap space as reported is accurate at the time of the query and that any subsequent allocation will be held the value. Parameters ---------- include_swap : bool Include available swap in the calculation. Returns ------- available : number The amount available. """ vm_stats = psutil.virtual_memory() available = vm_stats.available if include_swap: swap = psutil.swap_memory() available += return available def get_available_memory_darwin(include_swap=True): """Get the available memory on an Apple MacOS-like system For Darwin, swap space is dynamic and will attempt to use the whole of the boot partition. If the system has been configured to use swap from other sources besides the boot partition, that available space will not be included. Parameters ---------- include_swap : bool Include available swap in the calculation. Returns ------- available : number The amount available. """ vm_stats = psutil.virtual_memory() available = vm_stats.available if include_swap: # Attempt to determine amount of free disk space on the boot partition. try: swap = psutil.disk_usage('/private/var/vm').free except FileNotFoundError as exception: log.warn('Cannot determine available swap space.' f'Reason:\n' f'{"".join(traceback.format_exception(exception))}') swap = 0 available += swap return available