from __future__ import print_function import argparse import celery import celery.states import celery.events import collections from itertools import chain import logging import prometheus_client import signal import sys import threading import time import json import os from celery.utils.objects import FallbackContext import amqp.exceptions __VERSION__ = (1, 2, 0, 'final', 0) def decode_buckets(buckets_list): return [float(x) for x in buckets_list.split(',')] def get_histogram_buckets_from_evn(env_name): if env_name in os.environ: buckets = decode_buckets(os.environ.get(env_name)) else: if hasattr(prometheus_client.Histogram, 'DEFAULT_BUCKETS'): # pragma: no cover buckets = prometheus_client.Histogram.DEFAULT_BUCKETS else: # pragma: no cover # For prometheus-client < 0.3.0 we cannot easily access # the default buckets: buckets = (.005, .01, .025, .05, .075, .1, .25, .5, .75, 1.0, 2.5, 5.0, 7.5, 10.0, float('inf')) return buckets DEFAULT_BROKER = os.environ.get('BROKER_URL', 'redis://redis:6379/0') DEFAULT_ADDR = os.environ.get('DEFAULT_ADDR', '0.0.0.0:8888') DEFAULT_MAX_TASKS_IN_MEMORY = int(os.environ.get('DEFAULT_MAX_TASKS_IN_MEMORY', '10000')) RUNTIME_HISTOGRAM_BUCKETS = get_histogram_buckets_from_evn('RUNTIME_HISTOGRAM_BUCKETS') LATENCY_HISTOGRAM_BUCKETS = get_histogram_buckets_from_evn('LATENCY_HISTOGRAM_BUCKETS') DEFAULT_QUEUE_LIST = os.environ.get('QUEUE_LIST', []) LOG_FORMAT = '[%(asctime)s] %(name)s:%(levelname)s: %(message)s' TASKS = prometheus_client.Gauge( 'celery_tasks', 'Number of tasks per state', ['state']) TASKS_NAME = prometheus_client.Gauge( 'celery_tasks_by_name', 'Number of tasks per state and name', ['state', 'name']) TASKS_RUNTIME = prometheus_client.Histogram( 'celery_tasks_runtime_seconds', 'Task runtime (seconds)', ['name'], buckets=RUNTIME_HISTOGRAM_BUCKETS) WORKERS = prometheus_client.Gauge( 'celery_workers', 'Number of alive workers') LATENCY = prometheus_client.Histogram( 'celery_task_latency', 'Seconds between a task is received and started.', buckets=LATENCY_HISTOGRAM_BUCKETS) QUEUE_LENGTH = prometheus_client.Gauge( 'celery_queue_length', 'Number of tasks in the queue.', ['queue_name'] ) class MonitorThread(threading.Thread): """ MonitorThread is the thread that will collect the data that is later exposed from Celery using its eventing system. """ def __init__(self, app=None, *args, **kwargs): self._app = app self.log = logging.getLogger('monitor') self.log.info('Setting up monitor...') max_tasks_in_memory = kwargs.pop('max_tasks_in_memory', DEFAULT_MAX_TASKS_IN_MEMORY) self._state = self._app.events.State( max_tasks_in_memory=max_tasks_in_memory) self._known_states = set() self._known_states_names = set() self._tasks_started = dict() super(MonitorThread, self).__init__(*args, **kwargs) def run(self): # pragma: no cover self._monitor() def _process_event(self, evt): # Events might come in in parallel. Celery already has a lock # that deals with this exact situation so we'll use that for now. with self._state._mutex: if celery.events.group_from(evt['type']) == 'task': evt_state = evt['type'][5:] try: # Celery 4 state = celery.events.state.TASK_EVENT_TO_STATE[evt_state] except AttributeError: # pragma: no cover # Celery 3 task = celery.events.state.Task() task.event(evt_state) state = task.state if state == celery.states.STARTED: self._observe_latency(evt) self._collect_tasks(evt, state) def _observe_latency(self, evt): try: prev_evt = self._state.tasks[evt['uuid']] except KeyError: # pragma: no cover pass else: # ignore latency if it is a retry if prev_evt.state == celery.states.RECEIVED: LATENCY.observe( evt['local_received'] - prev_evt.local_received) def _collect_tasks(self, evt, state): if state in celery.states.READY_STATES: self._incr_ready_task(evt, state) else: # add event to list of in-progress tasks self._state._event(evt) self._collect_unready_tasks() def _incr_ready_task(self, evt, state): TASKS.labels(state=state).inc() try: # remove event from list of in-progress tasks event = self._state.tasks.pop(evt['uuid']) TASKS_NAME.labels(state=state, name=event.name).inc() if 'runtime' in evt: TASKS_RUNTIME.labels(name=event.name) \ .observe(evt['runtime']) except (KeyError, AttributeError): # pragma: no cover pass def _collect_unready_tasks(self): # count unready tasks by state cnt = collections.Counter(t.state for t in self._state.tasks.values()) self._known_states.update(cnt.elements()) for task_state in self._known_states: TASKS.labels(state=task_state).set(cnt[task_state]) # count unready tasks by state and name cnt = collections.Counter( (t.state, t.name) for t in self._state.tasks.values() if t.name) self._known_states_names.update(cnt.elements()) for task_state in self._known_states_names: TASKS_NAME.labels( state=task_state[0], name=task_state[1], ).set(cnt[task_state]) def _monitor(self): # pragma: no cover while True: try: self.log.info('Connecting to broker...') with self._app.connection() as conn: recv = self._app.events.Receiver(conn, handlers={ '*': self._process_event, }) setup_metrics(self._app) recv.capture(limit=None, timeout=None, wakeup=True) self.log.info("Connected to broker") except Exception: self.log.exception("Queue connection failed") setup_metrics(self._app) time.sleep(5) class WorkerMonitoringThread(threading.Thread): celery_ping_timeout_seconds = 5 periodicity_seconds = 5 def __init__(self, app=None, *args, **kwargs): self._app = app self.log = logging.getLogger('workers-monitor') super(WorkerMonitoringThread, self).__init__(*args, **kwargs) def run(self): # pragma: no cover while True: self.update_workers_count() time.sleep(self.periodicity_seconds) def update_workers_count(self): try: WORKERS.set(len(self._app.control.ping( timeout=self.celery_ping_timeout_seconds))) except Exception: # pragma: no cover self.log.exception("Error while pinging workers") class EnableEventsThread(threading.Thread): periodicity_seconds = 5 def __init__(self, app=None, *args, **kwargs): # pragma: no cover self._app = app self.log = logging.getLogger('enable-events') super(EnableEventsThread, self).__init__(*args, **kwargs) def run(self): # pragma: no cover while True: try: self.enable_events() except Exception: self.log.exception("Error while trying to enable events") time.sleep(self.periodicity_seconds) def enable_events(self): self._app.control.enable_events() class QueueLengthMonitoringThread(threading.Thread): periodicity_seconds = 30 def __init__(self, app, queue_list): # type: (celery.Celery, [str]) -> None self.celery_app = app self.queue_list = queue_list self.connection = self.celery_app.connection_or_acquire() if isinstance(self.connection, FallbackContext): self.connection = self.connection.fallback() super(QueueLengthMonitoringThread, self).__init__() def measure_queues_length(self): for queue in self.queue_list: try: length = self.connection.default_channel.queue_declare(queue=queue, passive=True).message_count except (amqp.exceptions.ChannelError,) as e: logging.warning("Queue Not Found: {}. Setting its value to zero. Error: {}".format(queue, str(e))) length = 0 self.set_queue_length(queue, length) def set_queue_length(self, queue, length): QUEUE_LENGTH.labels(queue).set(length) def run(self): # pragma: no cover while True: self.measure_queues_length() time.sleep(self.periodicity_seconds) def setup_metrics(app): """ This initializes the available metrics with default values so that even before the first event is received, data can be exposed. """ WORKERS.set(0) logging.info('Setting up metrics, trying to connect to broker...') try: registered_tasks = app.control.inspect().registered_tasks().values() except Exception: # pragma: no cover for metric in TASKS.collect(): for sample in metric.samples: TASKS.labels(**sample[1]).set(0) for metric in TASKS_NAME.collect(): for sample in metric.samples: TASKS_NAME.labels(**sample[1]).set(0) else: for state in celery.states.ALL_STATES: TASKS.labels(state=state).set(0) for task_name in set(chain.from_iterable(registered_tasks)): TASKS_NAME.labels(state=state, name=task_name).set(0) def start_httpd(addr): # pragma: no cover """ Starts the exposing HTTPD using the addr provided in a separate thread. """ host, port = addr.split(':') logging.info('Starting HTTPD on {}:{}'.format(host, port)) prometheus_client.start_http_server(int(port), host) def shutdown(signum, frame): # pragma: no cover """ Shutdown is called if the process receives a TERM signal. This way we try to prevent an ugly stacktrace being rendered to the user on a normal shutdown. """ logging.info("Shutting down") sys.exit(0) def main(): # pragma: no cover parser = argparse.ArgumentParser() parser.add_argument( '--broker', dest='broker', default=DEFAULT_BROKER, help="URL to the Celery broker. Defaults to {}".format(DEFAULT_BROKER)) parser.add_argument( '--transport-options', dest='transport_options', help=("JSON object with additional options passed to the underlying " "transport.")) parser.add_argument( '--addr', dest='addr', default=DEFAULT_ADDR, help="Address the HTTPD should listen on. Defaults to {}".format( DEFAULT_ADDR)) parser.add_argument( '--enable-events', action='store_true', help="Periodically enable Celery events") parser.add_argument( '--tz', dest='tz', help="Timezone used by the celery app.") parser.add_argument( '--verbose', action='store_true', default=False, help="Enable verbose logging") parser.add_argument( '--max_tasks_in_memory', dest='max_tasks_in_memory', default=DEFAULT_MAX_TASKS_IN_MEMORY, type=int, help="Tasks cache size. Defaults to {}".format( DEFAULT_MAX_TASKS_IN_MEMORY)) parser.add_argument( '--queue-list', dest='queue_list', default=DEFAULT_QUEUE_LIST, nargs='+', help="Queue List. Will be checked for its length." ) parser.add_argument( '--version', action='version', version='.'.join([str(x) for x in __VERSION__])) opts = parser.parse_args() if opts.verbose: logging.basicConfig(level=logging.DEBUG, format=LOG_FORMAT) else: logging.basicConfig(level=logging.INFO, format=LOG_FORMAT) signal.signal(signal.SIGINT, shutdown) signal.signal(signal.SIGTERM, shutdown) if opts.tz: os.environ['TZ'] = opts.tz time.tzset() logging.info('Setting up celery for {}'.format(opts.broker)) app = celery.Celery(broker=opts.broker) if opts.transport_options: try: transport_options = json.loads(opts.transport_options) except ValueError: print("Error parsing broker transport options from JSON '{}'" .format(opts.transport_options), file=sys.stderr) sys.exit(1) else: app.conf.broker_transport_options = transport_options setup_metrics(app) t = MonitorThread(app=app, max_tasks_in_memory=opts.max_tasks_in_memory) t.daemon = True t.start() w = WorkerMonitoringThread(app=app) w.daemon = True w.start() if opts.queue_list: if type(opts.queue_list) == str: queue_list = opts.queue_list.split(',') else: queue_list = opts.queue_list q = QueueLengthMonitoringThread(app=app, queue_list=queue_list) q.daemon = True q.start() e = None if opts.enable_events: e = EnableEventsThread(app=app) e.daemon = True e.start() start_httpd(opts.addr) t.join() w.join() if e is not None: e.join() if __name__ == '__main__': # pragma: no cover main()