Examples¶

Counter¶

Example of unread messages counter:

class Unread(redisext.counter.Counter):
    CONNECTION = Connection
    SERIALIZER = redisext.serializer.Numeric

could be used like:

>>> unread = Unread('messages')
>>> unread.get()  # key does not exist
>>> unread.incr()
1
>>> unread.incr(5)
6
>>> unread.get()
6

HashMap¶

Map could be used for simple and direct key’s value manipulations. For example storing Twitter’s username:

class TwitterUsername(redisext.hashmap.Map):
    CONNECTION = Connection
    SERIALIZER = redisext.serializer.String

and use-case:

>>> TwitterUsername(1).put('mylokin')
True
>>> TwitterUsername(1).get()
u'mylokin'

Map also could be used for cache purposes:

class Cache(redisext.hashmap.Map):
    CONNECTION = Connection
    SERIALIZER = redisext.serializer.Pickle

use-case example for cache:

>>> cache = Cache('hash')
>>> cache.put({'result': 'of', 'cpu intensive': 'calculations'})
True
>>> cache.get()
{'cpu intensive': 'calculations', 'result': 'of'}

Note

Also don’t forget to check redisext.hashmap.HashMap if you need to store more complicated data structures.

Pool¶

The simpliest example of pool usage is token pool:

class TokenPool(redisext.pool.Pool):
   CONNECTION = Connection
   SERIALIZER = redisext.serializer.String

and this pool could be used like:

>>> facebook = TokenPool('facebook')
>>> facebook.push('fb1')
True
>>> facebook.push('fb1')
False
>>> facebook.push('fb2')
True
>>> facebook.pop()
u'fb1'
>>> facebook.pop()
u'fb2'
>>> facebook.pop()
>>>

SortedSet¶

For your special needs check redisext.pool.SortedSet.

Queue¶

Right, task queue:

class Task(redisext.queue.Queue):
    CONNECTION = Connection
    SERIALIZER = redisext.serializer.Pickle

and it’s as simple as looks:

>>> task_queue = Task('data_processing')
>>> task_queue.pop()
>>> task_queue.push({'task': 't1'})
1L
>>> task_queue.push({'task': 't2'})
2L
>>> task_queue.push({'task': 't3'})
3L
>>> task_queue.pop()
{'task': 't1'}
>>> task_queue.pop()
{'task': 't2'}
>>> task_queue.pop()
{'task': 't3'}
>>> task_queue.pop()
>>>

Here is priority queue as well redisext.queue.PriorityQueue.

Lock¶

Lock based on Redis keys existence:

class TaskLock(redisext.lock.Lock):
    CONNECTION = Connection

usage:

>>> TaskLock('task1').acquire()
True
>>> TaskLock('task1').acquire()
False
>>> TaskLock('task1').release()
True
>>> TaskLock('task1').release()
False

Note

Imports section is intentionaly skiped, but for the order it is listed below:

import redisext.backend.redis

class Connection(redisext.backend.redis.Connection):
    MASTER = {'host': 'localhost', 'port': 6379, 'db': 0}