trollius_redis 0.0.1

PEP 3156 implementation of the redis protocol.

Redis client for the PEP 3156 Python event loop ported to Trollius.

This Redis library is a completely asynchronous, non-blocking client for a Redis server. It depends on trollius (asyncio compatible for PEP 3156) and therefore it requires Python 2.

If you’re new to asyncio, it can be helpful to check out the asyncio documentation first.

To see the original awesome driver, I advise you to take a look at asyncio-redis.

Features

• Works for the trollius asyncio-compatible (PEP3156) event loop

• No dependencies except trollius

• 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 git+https://github.com/benjolitz/trollius-redis.git

Documentation

View documentation at read-the-docs

The connection class

A trollius_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 trollius_redis.RedisProtocol instance; any Redis command of the protocol can be called directly at the connection.

import trollius as asyncio
from trollius import From
import trollius_redis

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

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

    # When finished, close the connection.
    connection.close()

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

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 trollius as asyncio
from trollius import From
import trollius_redis

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

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

    # When finished, close the connection pool.
    connection.close()

Transactions example

import trollius as asyncio
from trollius import From
import trollius_redis

@asyncio.coroutine
def example():
    # Create Redis connection
    connection = yield From(trollius_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'))
    f2 = yield From(transaction.set('another_key', 'another_value'))

    # Commit transaction
    yield From(transaction.exec())

    # Retrieve results
    result1 = yield From(f1)
    result2 = yield From(f2)

    # When finished, close the connection pool.
    connection.close()

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 trollius as asyncio
from trollius import From
import trollius_redis

@asyncio.coroutine
def example():
    # Create connection
    connection = yield From(trollius_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)

    # When finished, close the connection.
    connection.close()

LUA Scripting example

import trollius as asyncio
from trollius import From
import trollius_redis

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

@asyncio.coroutine
def example():
    connection = yield From(trollius_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

    # When finished, close the connection.
    connection.close()

Example using the Protocol class

import trollius as asyncio
from trollius import From
import trollius_redis

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

    # Create Redis connection
    transport, protocol = yield From(loop.create_connection(
                trollius_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)

    # Close transport when finished.
    transport.close()

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