Source code for zarr.attrs

import warnings
from import MutableMapping

from import Store, StoreV3
from zarr.util import json_dumps

[docs]class Attributes(MutableMapping): """Class providing access to user attributes on an array or group. Should not be instantiated directly, will be available via the `.attrs` property of an array or group. Parameters ---------- store : MutableMapping The store in which to store the attributes. key : str, optional The key under which the attributes will be stored. read_only : bool, optional If True, attributes cannot be modified. cache : bool, optional If True (default), attributes will be cached locally. synchronizer : Synchronizer Only necessary if attributes may be modified from multiple threads or processes. """ def __init__(self, store, key='.zattrs', read_only=False, cache=True, synchronizer=None): self._version = getattr(store, '_store_version', 2) _Store = Store if self._version == 2 else StoreV3 = _Store._ensure_store(store) self.key = key self.read_only = read_only self.cache = cache self._cached_asdict = None self.synchronizer = synchronizer def _get_nosync(self): try: data =[self.key] except KeyError: d = dict() if self._version > 2: d['attributes'] = {} else: d = return d
[docs] def asdict(self): """Retrieve all attributes as a dictionary.""" if self.cache and self._cached_asdict is not None: return self._cached_asdict d = self._get_nosync() if self._version == 3: d = d['attributes'] if self.cache: self._cached_asdict = d return d
[docs] def refresh(self): """Refresh cached attributes from the store.""" if self.cache: if self._version == 2: self._cached_asdict = self._get_nosync() else: self._cached_asdict = self._get_nosync()['attributes']
def __contains__(self, x): return x in self.asdict()
[docs] def __getitem__(self, item): return self.asdict()[item]
def _write_op(self, f, *args, **kwargs): # guard condition if self.read_only: raise PermissionError('attributes are read-only') # synchronization if self.synchronizer is None: return f(*args, **kwargs) else: with self.synchronizer[self.key]: return f(*args, **kwargs)
[docs] def __setitem__(self, item, value): self._write_op(self._setitem_nosync, item, value)
def _setitem_nosync(self, item, value): # load existing data d = self._get_nosync() # set key value if self._version == 2: d[item] = value else: d['attributes'][item] = value # _put modified data self._put_nosync(d)
[docs] def __delitem__(self, item): self._write_op(self._delitem_nosync, item)
def _delitem_nosync(self, key): # load existing data d = self._get_nosync() # delete key value if self._version == 2: del d[key] else: del d['attributes'][key] # _put modified data self._put_nosync(d)
[docs] def put(self, d): """Overwrite all attributes with the key/value pairs in the provided dictionary `d` in a single operation.""" if self._version == 2: self._write_op(self._put_nosync, d) else: self._write_op(self._put_nosync, dict(attributes=d))
def _put_nosync(self, d): d_to_check = d if self._version == 2 else d["attributes"] if not all(isinstance(item, str) for item in d_to_check): # TODO: Raise an error for non-string keys # raise TypeError("attribute keys must be strings") warnings.warn( "only attribute keys of type 'string' will be allowed in the future", DeprecationWarning, stacklevel=2 ) try: d_to_check = {str(k): v for k, v in d_to_check.items()} except TypeError as ex: # pragma: no cover raise TypeError("attribute keys can not be stringified") from ex if self._version == 2: d = d_to_check else: d["attributes"] = d_to_check if self._version == 2:[self.key] = json_dumps(d) if self.cache: self._cached_asdict = d else: if self.key in # Cannot write the attributes directly to JSON, but have to # store it within the pre-existing attributes key of the v3 # metadata. # Note: this changes the store.counter result in test_caching_on! meta =[self.key]) if 'attributes' in meta and 'filters' in meta['attributes']: # need to preserve any existing "filters" attribute d['attributes']['filters'] = meta['attributes']['filters'] meta['attributes'] = d['attributes'] else: meta = d[self.key] = json_dumps(meta) if self.cache: self._cached_asdict = d['attributes'] # noinspection PyMethodOverriding
[docs] def update(self, *args, **kwargs): """Update the values of several attributes in a single operation.""" self._write_op(self._update_nosync, *args, **kwargs)
def _update_nosync(self, *args, **kwargs): # load existing data d = self._get_nosync() # update if self._version == 2: d.update(*args, **kwargs) else: d['attributes'].update(*args, **kwargs) # _put modified data self._put_nosync(d)
[docs] def keys(self): return self.asdict().keys()
[docs] def __iter__(self): return iter(self.asdict())
[docs] def __len__(self): return len(self.asdict())
def _ipython_key_completions_(self): return sorted(self)