platypush/platypush/backend/redis.py

77 lines
2.1 KiB
Python

import json
from redis import Redis
from platypush.backend import Backend
from platypush.message import Message
class RedisBackend(Backend):
"""
Backend that reads messages from a configured Redis queue (default:
``platypush_bus_mq``) and posts them to the application bus. Very
useful when you have plugin whose code is executed in another process
and can't post events or requests to the application bus.
Requires:
* **redis** (``pip install redis``)
"""
def __init__(self, queue='platypush_bus_mq', redis_args={}, *args, **kwargs):
"""
:param queue: Queue name to listen on (default: ``platypush_bus_mq``)
:type queue: str
:param redis_args: Arguments that will be passed to the redis-py constructor (e.g. host, port, password), see http://redis-py.readthedocs.io/en/latest/
:type redis_args: dict
"""
super().__init__(*args, **kwargs)
self.queue = queue
self.redis_args = redis_args
self.redis = Redis(**self.redis_args)
def send_message(self, msg, queue_name=None):
if queue_name:
self.redis.rpush(queue_name, msg)
else:
self.redis.rpush(self.queue, msg)
def get_message(self, queue_name=None):
queue = queue_name or self.queue
msg = self.redis.blpop(queue)[1].decode('utf-8')
try:
msg = Message.build(json.loads(msg))
except:
try:
import ast
msg = Message.build(ast.literal_eval(msg))
except:
try:
msg = json.loads(msg)
except Exception as e:
self.logger.exception(e)
return msg
def run(self):
super().run()
self.logger.info('Initialized Redis backend on queue {} with arguments {}'.
format(self.queue, self.redis_args))
while not self.should_stop():
msg = self.get_message()
self.logger.info('Received message on the Redis backend: {}'.format(msg))
self.on_message(msg)
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