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import pendulum
from airflow.models import BaseOperator, SkipMixin
[docs]class LatestOnlyOperator(BaseOperator, SkipMixin):
"""
Allows a workflow to skip tasks that are not running during the most
recent schedule interval.
If the task is run outside of the latest schedule interval, all
directly downstream tasks will be skipped.
"""
[docs] ui_color = '#e9ffdb' # nyanza
[docs] def execute(self, context):
# If the DAG Run is externally triggered, then return without
# skipping downstream tasks
if context['dag_run'] and context['dag_run'].external_trigger:
self.log.info("Externally triggered DAG_Run: allowing execution to proceed.")
return
now = pendulum.utcnow()
left_window = context['dag'].following_schedule(
context['execution_date'])
right_window = context['dag'].following_schedule(left_window)
self.log.info(
'Checking latest only with left_window: %s right_window: %s now: %s',
left_window, right_window, now
)
if not left_window < now <= right_window:
self.log.info('Not latest execution, skipping downstream.')
downstream_tasks = context['task'].get_flat_relatives(upstream=False)
self.log.debug("Downstream task_ids %s", downstream_tasks)
if downstream_tasks:
self.skip(context['dag_run'],
context['ti'].execution_date,
downstream_tasks)
self.log.info('Done.')
else:
self.log.info('Latest, allowing execution to proceed.')