redis-taxon

Taxon

Taxon is a tagged data store with persistence to a Redis backend. It allows you to organize and query Redis data sets with tags, and is implemented as a library instead of a stand-alone server.

Features

• Fully queryable. Supports expressions using And, Or, and Not operations as well as direct tag lookup.
• Persistent. Data is stored in Redis.

Getting Started

First install the taxon package with pip:

::

$ pip install -U redis-taxon

Then you can instantiate Taxon stores in your code that wrap Redis objects from redis-py_.

.. _redis-py: https://github.com/andymccurdy/redis-py

::

import redis
import taxon

t = taxon.Taxon(redis.Redis())

To tag data, use the tag method on a taxon.Taxon object. The first argument is the tag to use, and the following variable arguments are the items to tag.

::

t.tag('feature', 'issue-312', 'issue-199', 'issue-321')
t.tag('experimental', 'issue-199')

Querying

Taxon allows the dataset to be queried with arbitrary expressions and supports And, Or, and Not operations. The query syntax is a small DSL implemented directly in Python. Most queries are issued with the find method, which returns a set of items.

::

from taxon import Taxon
from taxon.query import And, Or, Not

# get issue tracker items with no action required
t = Taxon(my_redis_object)
items = t.find(Or('invalid', 'closed', 'wontfix'))

Query expressions can also be arbitrarily complex. Queries issued through the query method return both the name of the Redis key and a list of items.

::

# get issue tracker items marked feature or bugfix, but not experimental
_, items = t.query(And(Or('feature', 'bugfix'), Not('experimental')))

There is an alternate query syntax available using the Tag member from taxon.query which uses operators instead of classes. The operators are & for And, | for Or, and ~ for Not. The above query in operator syntax looks like this:

::

from taxon.query import Tag
items = t.find((Tag('feature') | Tag('bugfix')) & ~Tag('experimental'))

Data Encoding

You can also interface better with Python data types by subclassing Taxon and providing encode and decode methods.

::

import json
from redis import Redis
from taxon import Taxon
from taxon.query import Tag

class JsonTaxon(Taxon):
    def encode(self, data): return json.dumps(data)
    def decode(self, data): return json.loads(data)

t = JsonTaxon(Redis())
t.tag('foo', {'foo': 'bar'})
_, items = t.query(Tag('foo'))

MIT License

Copyright (c) 2012 Justin Poliey [e-mail]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.