pgnotify: A python library to easily LISTEN to PostgreSQL NOTIFY notifications
Example
LISTEN to and process NOTIFY events with a simple for loop, like so:
from pgnotify import await_pg_notifications
for notification in await_pg_notifications(
'postgresql:///example',
['channel1', 'channel2']):
print(notification.channel)
print(notification.payload)Install
Installable with any python package manager from the python package index, eg:
pip install pgnotifyAll the bells and whistles
You can also handle timeouts and signals, as in this more fully-fleshed example:
import signal
from pgnotify import await_pg_notifications, get_dbapi_connection
# the first parameter of the await_pg_notifications
# loop is a dbapi connection in autocommit mode
CONNECT = "postgresql:///example"
# use this convenient method to create the right connection
# from a database URL
e = get_dbapi_connection(CONNECT)
SIGNALS_TO_HANDLE = [signal.SIGINT, signal.SIGTERM]
for n in await_pg_notifications(
e,
["hello", "hello2"],
timeout=10,
yield_on_timeout=True,
handle_signals=SIGNALS_TO_HANDLE,
):
# the integer code of the signal is yielded on each
# occurrence of a handled signal
if isinstance(n, int):
sig = signal.Signals(n)
print(f"handling {sig.name}, stopping")
break
# the `yield_on_timeout` option makes the
# loop yield `None` on timeout
elif n is None:
print("timeout, continuing")
# handle the actual notify occurrences here
else:
print((n.pid, n.channel, n.payload))Further documentation to come.
