Question on StackOverflow. Has anyone else dealt with this

I have a super simple test DAG that looks like this:

from datetime import datetime
from airflow.models import DAGfrom airflow.operators.python_operator
import PythonOperator

  start_date=datetime(2017, 9, 9, 4, 0, 0, 0), #..EC2 time. Equal to
11pm hora México
  schedule_interval='@once' #externally triggered
def ticker_function():
    with open('/tmp/ticker', 'a') as outfile:

time_ticker = PythonOperator(

Since upgrading to apache-airflow v1.9 this DAG is hung and won't run.
Digging into the scheduler logs I found the error trace:

[2018-02-12 17:03:06,259] {} INFO - DAG(s)
dict_keys(['scheduler_test_dag']) retrieved from
17:03:06,315] {} INFO - Processing
scheduler_test_dag[2018-02-12 17:03:06,320] {} ERROR - Got
an exception! Propagating...Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/airflow/", line
371, in helper
  File "/usr/local/lib/python3.5/dist-packages/airflow/utils/",
line 50, in wrapper
result = func(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/airflow/", line
1792, in process_file
self._process_dags(dagbag, dags, ti_keys_to_schedule)
  File "/usr/local/lib/python3.5/dist-packages/airflow/", line
1388, in _process_dags
dag_run = self.create_dag_run(dag)
  File "/usr/local/lib/python3.5/dist-packages/airflow/utils/",
line 50, in wrapper
result = func(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/airflow/", line
807, in create_dag_runif next_start <= now:TypeError: unorderable
types: NoneType() <= datetime.datetime()

Where is this error coming from? The only thing that I can think of is that
the usage of scheduler_interval='@once' has changed, which is the one thing
that this DAG has in common with one other broken DAG on my server since
the v1.9 upgrade. Otherwise it's the most basic DAG ever--doesn't seem like
there should be a problem. Previously I was using the basic pip install
before switching to the apache-airflow repo.

Here's a screenshot of the Web UI. Everything seems to be working alright,
except the top and bottom DAGS which have scheduling interval set to @once and
are indefinitely hung:

Any thoughts?


*Aaron Polhamus*
*Chief Technology Officer *

Cel (México): +52 (55) 1951-5612
Cell (USA): +1 (206) 380-3948
Tel: +52 (55) 1168 9757 - Ext. 181

***Por favor referirse a nuestra página web 
<> para más información 
acerca de nuestras políticas de privacidad.*

Reply via email to