Can I use celery for every-second task? - celery

Question

I'm running a task every second, and it seems celery doesn't actually perform the task every second.
I guess celery might be a good scheduler for every 1 minute task, but might not be adequte for every second task.
Here's the picture which illustrates what I mean.
I'm using the following options
'schedule': 1.0,
'args': [],
'options': {
'expires': 3
}
And I'm using celery 4.0.0

Answer 1

Yes, Celery actually handles times as low as 1 second, and possibly lower since it takes a float. See this entry of periodic tasks in the docs http://docs.celeryproject.org/en/latest/userguide/periodic-tasks.html:
from celery import Celery
from celery.schedules import crontab
app = Celery()
#app.on_after_configure.connect
def setup_periodic_tasks(sender, **kwargs):
# Calls test('hello') every 10 seconds.
sender.add_periodic_task(10.0, test.s('hello'), name='add every 10')
# Calls test('world') every 30 seconds
sender.add_periodic_task(30.0, test.s('world'), expires=10)
# Executes every Monday morning at 7:30 a.m.
sender.add_periodic_task(
crontab(hour=7, minute=30, day_of_week=1),
test.s('Happy Mondays!'),
)
#app.task
def test(arg):
print(arg)
A better written example can be found 1/3 the way down https://github.com/celery/celery/issues/3589:
# file: tasks.py
from celery import Celery
celery = Celery('tasks', broker='pyamqp://guest#localhost//')
#celery.task
def add(x, y):
return x + y
#celery.on_after_configure.connect
def add_periodic(**kwargs):
celery.add_periodic_task(10.0, add.s(2,3), name='add every 10')
So sender is the actual Celery broker, i.e. app = Celery()