IODict

iodict is a thread safe dictionary implementation which uses a pure python object store. The dictionary implementation follows the Dict API, but stores items using their birthtime allowing users to treat this datastore as a file system backed OrderedDict.

Items in the object store use file system attributes, when available to store key and birthtime information. File system attributes enhance the capability of the object store; however, they're not required. In the event xattrs are not available, file stat is used for file creation time along with base64 encoding for object keys.

Usage

import iodict
data = iodict.IODict(path='/tmp/iodict')  # Could be any path on the file system
data["key"] = "value"
data
{'key': "value"}

dir(data)
['__class__',
 '__delattr__',
 '__delitem__',
 '__dict__',
 '__dir__',
 '__doc__',
 '__enter__',
 '__eq__',
 '__exit__',
 '__format__',
 '__ge__',
 '__getattribute__',
 '__getitem__',
 '__gt__',
 '__hash__',
 '__init__',
 '__init_subclass__',
 '__iter__',
 '__le__',
 '__len__',
 '__lt__',
 '__module__',
 '__ne__',
 '__new__',
 '__reduce__',
 '__reduce_ex__',
 '__repr__',
 '__setattr__',
 '__setitem__',
 '__sizeof__',
 '__str__',
 '__subclasshook__',
 '__weakref__',
 '_db_path',
 '_encoder',
 '_lock',
 'clear',
 'copy',
 'fromkeys',
 'get',
 'items',
 'keys',
 'pop',
 'popitem',
 'setdefault',
 'update',
 'values']

When running in a multiprocessing / threading application, a lock is required to be passed into the iodict class.

import threading

import iodict
data = iodict.IODict(path='/tmp/iodict', lock=threading.Lock)

By default, if no lock is provided, a multiprocessing lock will be created.

The lock object allows the iodict to respect the locking paradigm of the executing application.