CherryPy PostgreSQL pgpubsub

CherryPy_PGrepub.py

import threading
import pgpubsub
import cherrypy
from cherrypy.process import plugins

class PGrepub(plugins.SimplePlugin):
    """
    Plugin that listens to Postresql notification channels and publishes
    the payload unmodified to a channel on the CherryPy bus.
    
    Requires psycopg2 and pgpubsub https://pypi.python.org/pypi/pgpubsub/

    channels: a dictionary holding the conversion of channel names,
              {PG notify channel : CP publish channel}
    """
    thread = None
    def __init__(self, bus, dsn, channels):
        plugins.SimplePlugin.__init__(self, bus)
        self.pubsub = pgpubsub.connect(dsn)
        self.channels = channels

    def start(self):
        if not self.thread:
            self.bus.log('Starting up PGrepub')
            self.thread = threading.Thread(target=self.run)
            self.thread.start()

    def stop(self):
        if self.thread:
            self.bus.log('Shut down PGrepub')
            self.thread.join()

    def run(self):
        for channel in self.channels:
            self.pubsub.listen(channel)
        for event in self.pubsub.events(select_timeout=1):
            cherrypy.engine.publish(self.channels[event.channel], event.payload)


dsn = "dbname=YourDB user=PasMoi password=Super@Secret"
channels = {'pg_foo': 'cp_foo', 'pg_bar': 'cp_bar'}
PGrepub(cherrypy.engine, dsn, channels).subscribe()