pubsub using postgres listen/notify

auto_notify.sql

CREATE OR REPLACE FUNCTION object_notify() RETURNS trigger AS $$
DECLARE
BEGIN
  PERFORM pg_notify('object_updated',CAST(NEW.id AS text));
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER object_post_insert_notify AFTER UPDATE ON objects FOR EACH ROW EXECUTE PROCEDURE object_notify();

listen_notify_postgres.py

#!/usr/bin/env python
import psycopg2
import select

DSN = 'postgres://postgres@localhost:5433/pubsub'

def handle_notification(notify):
    print(notify)

conn = psycopg2.connect(DSN)
conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)

curs = conn.cursor()
curs.execute("LISTEN test;")

while True:
    if select.select([conn],[],[],5) == ([],[],[]):
        pass
    else:
        conn.poll()
        while conn.notifies:
            notify = conn.notifies.pop()
            handle_notification(notify)