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Python Library for NoSQL database record versioning

Project description

A Python library for NoSQL record versioning.


To install the latest release on PyPi, simply run:

pip install nosql_versioning

Or to install the latest development version, run:

git clone
cd nosql_versioning
python install

Quick Tutorial

>>> from nosql_versioning import schema
>>> import json
>>> version, Record = schema(decode=json.loads)
>>> @version()
>>> class Recordv0(object):
>>>     def __init__(self, data):
>>>         self.old_name = data['old_name']
>>> @version(1)
>>> class Recordv1(object):
>>>     def __init__(self, value=None, *args, data=None):
>>>         if data:
>>>             self.new_name = data['new_name']
>>>         else:
>>>             self.new_name = value
>>>     @staticmethod
>>>     def migrate(data):
>>>         data['new_name'] = data['old_name']
>>>         del data['old_name']
>>>     @staticmethod
>>>     def a_staticmethod(n):
>>>         print(n * 2)
>>> rec = Record('{"_ver": 0, "old_name": 1}')
>>> print(rec.new_name)
>>> rec = Record(value=42)         # custom constructor can also be used
>>> print(rec.new_name)
>>> Record.a_staticmethod(42)      # static methods defined in the latest version can be used

API Reference

schema(decode=decode, version=get_version)

Create a class descriptor to specify record classes of different version, and a Record initializer to instantiate the latest record from data, or to migrate data to the latest version.

  • decode: Deserialize objects retrieved from database. By default no decoding will be applied.

  • version: Get version from record. By default it’s data.get('_ver')

  • version: A class descriptor to specify record version.

  • Record: A initializer that to construct defined Record class. Migrate if data is not the latest version.


A class descriptor to specify record class of version N.

  • n: Version. Must be a integer.

  • VersionConflictionException: When a version is defined twice.

Record(data=None, *args, **kwargs)

The initializer to migrate record to latest and instantiate record class.

  • data: If only this argument is specified, decode(data) will be used to instantiate the latest record class. (Migrate if needed.)

  • args, kwargs: If not only data is specified, all arguments will be passed to instantiate the latest record class. No migration.

Migration from Version N-1 to N will use static method migrate in record class version N.

In case there is no version specified, migration from None to 0 will use static method migrate in record class Version 0.


This project is released under the terms of the MIT Open Source License. View LICENSE.txt for more information.

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