Ignore scheduling if DESTALINATOR_RUN_ONCE is used

[dshackith]

Scheduler still cares about local timezone on container/server and will fail if not set, even if DESTALINATOR_RUN_ONCE is set. All scheduling should be ignored (and code not run) if DESTALINATOR_RUN_ONCE is set.

This is relevant when running Destalinator as a Kubernetes ChronJob that handles the scheduling.

[kmarekspartz]

Relevant lines: https://github.com/randsleadershipslack/destalinator/blob/master/scheduler.py#L47

My guess is you updated settings.yml to remove schedule_hour?

[dshackith]

I have DESTALINATOR_SCHEDULE_HOUR=5 set in the environment, and configuration.yaml still contains schedule_hour: 4. The code does not seem to allow for no schedule, if I am using scheduler.py, but that is the only place where RUN_ONCE is detected.

[kmarekspartz]

Interesting... what is the error message you're getting?

[dshackith]

Traceback (most recent call last):
File "scheduler.py", line 25, in
@sched.scheduled_job("cron", **schedule_kwargs)
File "/usr/local/lib/python3.6/site-packages/apscheduler/schedulers/base.py", line 371, in inner
next_run_time, jobstore, executor, True, **trigger_args)
File "/usr/local/lib/python3.6/site-packages/apscheduler/schedulers/base.py", line 330, in add_job
'trigger': self._create_trigger(trigger, trigger_args),
File "/usr/local/lib/python3.6/site-packages/apscheduler/schedulers/base.py", line 782, in _create_trigger
return self._create_plugin_instance('trigger', trigger, trigger_args)
File "/usr/local/lib/python3.6/site-packages/apscheduler/schedulers/base.py", line 768, in _create_plugin_instance
return plugin_cls(**constructor_kwargs)
File "/usr/local/lib/python3.6/site-packages/apscheduler/triggers/cron/init.py", line 48, in init
self.timezone = astimezone(timezone)
File "/usr/local/lib/python3.6/site-packages/apscheduler/util.py", line 80, in astimezone
raise ValueError('Unable to determine the name of the local timezone -- use an explicit timezone instead')
ValueError: Unable to determine the name of the local timezone -- use an explicit timezone instead

[kmarekspartz]

Very weird. This is with something like docker run -it -e DESTALINATOR_RUN_ONCE=true destalinator ?

[dshackith]

Exactly. But, there are a couple other differences:

1. I am using python:alpine3.6 for the base
2. I have added tini for zombie reaping (see https://github.com/krallin/tini)

[kmarekspartz]

Looks related to agronholm/apscheduler#87. I don't think this bug has anything to do with RUN_ONCE, but we could skip the scheduler all together and avoid this with RUN_ONCE.

[dshackith]

Also fixed by setting /etc/timezone in Dockerfile: https://serverfault.com/questions/683605/docker-container-time-timezone-will-not-reflect-changes

[dshackith]

But I still don't think the scheduler should care about timezone if no scheduling is being done.

[kmarekspartz]

Agreed. Sending a MR shortly.

[kmarekspartz]

MR: #157