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How to use PostgreSQL's LISTEN/NOTIFY as a simple message queue with psycopg2 and asyncio
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| import asyncio | |
| import psycopg2 | |
| # dbname should be the same for the notifying process | |
| conn = psycopg2.connect(host="localhost", dbname="example", user="example", password="example") | |
| conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT) | |
| cursor = conn.cursor() | |
| cursor.execute(f"LISTEN match_updates;") | |
| def handle_notify(): | |
| conn.poll() | |
| for notify in conn.notifies: | |
| print(notify.payload) | |
| conn.notifies.clear() | |
| # It works with uvloop too: | |
| # import uvloop | |
| # loop = uvloop.new_event_loop() | |
| # asyncio.set_event_loop(loop) | |
| loop = asyncio.get_event_loop() | |
| loop.add_reader(conn, handle_notify) | |
| loop.run_forever() |
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| import time | |
| import psycopg2 | |
| # dbname should be the same for the listening process | |
| conn = psycopg2.connect(host="localhost", dbname="example", user="example", password="example") | |
| cursor = conn.cursor() | |
| conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT) | |
| while True: | |
| val = time.time() | |
| cursor.execute(f"NOTIFY match_updates, '{val}';") | |
| time.sleep(1) |
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