asyncio-redis 0.9

PEP 3156 implementation of the redis protocol.

Features

• Works for the asyncio (PEP3156) event loop

• No dependencies

• Connection pooling

• Automatic conversion from unicode (Python) to bytes (inside Redis.)

• Bytes and str protocols.

• Completely tested

• Blocking calls and transactions supported

• Streaming of some multi bulk replies

• Pubsub support

Installation

pip install asyncio_redis

Documentation

View documentation at read-the-docs

The connection class

A asyncio_redis.Connection instance will take care of the connection and will automatically reconnect, using a new transport when the connection drops. This connection class also acts as a proxy to a asyncio_redis.RedisProtocol instance; any Redis command of the protocol can be called directly at the connection.

import asyncio
import asyncio_redis

@asyncio.coroutine
def example():
    # Create Redis connection
    connection = yield from asyncio_redis.Connection.create(host='localhost', port=6379)

    # Set a key
    yield from connection.set('my_key', 'my_value')

Connection pooling

Requests will automatically be distributed among all connections in a pool. If a connection is blocking because of –for instance– a blocking rpop, another connection will be used for new commands.

import asyncio
import asyncio_redis

@asyncio.coroutine
def example():
    # Create Redis connection
    connection = yield from asyncio_redis.Pool.create(host='localhost', port=6379, poolsize=10)

    # Set a key
    yield from connection.set('my_key', 'my_value')

Transactions example

import asyncio
import asyncio_redis

@asyncio.coroutine
def example():
    # Create Redis connection
    connection = yield from asyncio_redis.Pool.create(host='localhost', port=6379, poolsize=10)

    # Create transaction
    transaction = yield from connection.multi()

    # Run commands in transaction (they return future objects)
    f1 = yield from transaction.set('key', 'value')
    f1 = yield from transaction.set('another_key', 'another_value')

    # Commit transaction
    yield from transaction.exec()

    # Retrieve results
    result1 = yield from f1
    result2 = yield from f2

It’s recommended to use a large enough poolsize. A connection will be occupied as long as there’s a transaction running in there.

Pubsub example

import asyncio
import asyncio_redis

@asyncio.coroutine
def example():
    # Create connection
    connection = yield from asyncio_redis.Connection.create(host='localhost', port=6379)

    # Create subscriber.
    subscriber = yield from connection.start_subscribe()

    # Subscribe to channel.
    yield from subscriber.subscribe([ 'our-channel' ])

    # Inside a while loop, wait for incoming events.
    while True:
        reply = yield from subscriber.next_published()
        print('Received: ', repr(reply.value), 'on channel', reply.channel)

LUA Scripting example

import asyncio
import asyncio_redis

code = \
"""
local value = redis.call('GET', KEYS[1])
value = tonumber(value)
return value * ARGV[1]
"""

@asyncio.coroutine
def example():
    connection = yield from asyncio_redis.Connection.create(host='localhost', port=6379)

    # Set a key
    yield from connection.set('my_key', '2')

    # Register script
    multiply = yield from connection.register_script(code)

    # Run script
    script_reply = yield from multiply.run(keys=['my_key'], args=['5'])
    result = yield from script_reply.return_value()
    print(result) # prints 2 * 5

Example using the Protocol class

import asyncio
import asyncio_redis

@asyncio.coroutine
def example():
    loop = asyncio.get_event_loop()

    # Create Redis connection
    transport, protocol = yield from loop.create_connection(
                asyncio_redis.RedisProtocol, 'localhost', 6379)

    # Set a key
    yield from protocol.set('my_key', 'my_value')

    # Get a key
    result = yield from protocol.get('my_key')
    print(result)

if __name__ == '__main__':
    asyncio.get_event_loop().run_until_complete(example())