This document describes the current stable version of Celery (5.0). For development docs, go here.

Source code for

"""Utility to dump events to screen.

This is a simple program that dumps events to the console
as they happen.  Think of it like a `tcpdump` for Celery events.
import sys
from datetime import datetime

from import app_or_default
from celery.utils.functional import LRUCache
from celery.utils.time import humanize_seconds

__all__ = ('Dumper', 'evdump')

TASK_NAMES = LRUCache(limit=0xFFF)

    'worker-offline': 'shutdown',
    'worker-online': 'started',
    'worker-heartbeat': 'heartbeat',

-> Cannot connect to %s: %s.
Trying again %s

def humanize_type(type):
        return HUMAN_TYPES[type.lower()]
    except KeyError:
        return type.lower().replace('-', ' ')

[docs]class Dumper: """Monitor events.""" def __init__(self, out=sys.stdout): self.out = out
[docs] def say(self, msg): print(msg, file=self.out) # need to flush so that output can be piped. try: self.out.flush() except AttributeError: # pragma: no cover pass
[docs] def on_event(self, ev): timestamp = datetime.utcfromtimestamp(ev.pop('timestamp')) type = ev.pop('type').lower() hostname = ev.pop('hostname') if type.startswith('task-'): uuid = ev.pop('uuid') if type in ('task-received', 'task-sent'): task = TASK_NAMES[uuid] = '{}({}) args={} kwargs={}' \ .format(ev.pop('name'), uuid, ev.pop('args'), ev.pop('kwargs')) else: task = TASK_NAMES.get(uuid, '') return self.format_task_event(hostname, timestamp, type, task, ev) fields = ', '.join( f'{key}={ev[key]}' for key in sorted(ev) ) sep = fields and ':' or '' self.say(f'{hostname} [{timestamp}] {humanize_type(type)}{sep} {fields}')
[docs] def format_task_event(self, hostname, timestamp, type, task, event): fields = ', '.join( f'{key}={event[key]}' for key in sorted(event) ) sep = fields and ':' or '' self.say(f'{hostname} [{timestamp}] {humanize_type(type)}{sep} {task} {fields}')
[docs]def evdump(app=None, out=sys.stdout): """Start event dump.""" app = app_or_default(app) dumper = Dumper(out=out) dumper.say('-> evdump: starting capture...') conn = app.connection_for_read().clone() def _error_handler(exc, interval): dumper.say(CONNECTION_ERROR % ( conn.as_uri(), exc, humanize_seconds(interval, 'in', ' ') )) while 1: try: conn.ensure_connection(_error_handler) recv =, handlers={'*': dumper.on_event}) recv.capture() except (KeyboardInterrupt, SystemExit): return conn and conn.close() except conn.connection_errors + conn.channel_errors: dumper.say('-> Connection lost, attempting reconnect')
if __name__ == '__main__': # pragma: no cover evdump()