Source code for airflow.models.skipmixin

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from airflow.models.taskinstance import TaskInstance
from airflow.utils import timezone
from airflow.utils.db import create_session, provide_session
from airflow.utils.log.logging_mixin import LoggingMixin
from airflow.utils.state import State

import six
from typing import Set

# The key used by SkipMixin to store XCom data.
[docs]XCOM_SKIPMIXIN_KEY = "skipmixin_key"
# The dictionary key used to denote task IDs that are skipped
[docs]XCOM_SKIPMIXIN_SKIPPED = "skipped"
# The dictionary key used to denote task IDs that are followed
[docs]XCOM_SKIPMIXIN_FOLLOWED = "followed"
[docs]class SkipMixin(LoggingMixin):
[docs] def _set_state_to_skipped(self, dag_run, execution_date, tasks, session): """ Used internally to set state of task instances to skipped from the same dag run. """ task_ids = [d.task_id for d in tasks] now = timezone.utcnow() if dag_run: session.query(TaskInstance).filter( TaskInstance.dag_id == dag_run.dag_id, TaskInstance.execution_date == dag_run.execution_date, TaskInstance.task_id.in_(task_ids), ).update( { TaskInstance.state: State.SKIPPED, TaskInstance.start_date: now, TaskInstance.end_date: now, }, synchronize_session=False, ) else: assert execution_date is not None, "Execution date is None and no dag run" self.log.warning("No DAG RUN present this should not happen") # this is defensive against dag runs that are not complete for task in tasks: ti = TaskInstance(task, execution_date=execution_date) ti.state = State.SKIPPED ti.start_date = now ti.end_date = now session.merge(ti)
@provide_session
[docs] def skip( self, dag_run, execution_date, tasks, session=None, ): """ Sets tasks instances to skipped from the same dag run. If this instance has a `task_id` attribute, store the list of skipped task IDs to XCom so that NotPreviouslySkippedDep knows these tasks should be skipped when they are cleared. :param dag_run: the DagRun for which to set the tasks to skipped :param execution_date: execution_date :param tasks: tasks to skip (not task_ids) :param session: db session to use """ if not tasks: return self._set_state_to_skipped(dag_run, execution_date, tasks, session) session.commit() # SkipMixin may not necessarily have a task_id attribute. Only store to XCom if one is available. try: task_id = self.task_id except AttributeError: task_id = None if task_id is not None: from airflow.models.xcom import XCom XCom.set( key=XCOM_SKIPMIXIN_KEY, value={XCOM_SKIPMIXIN_SKIPPED: [d.task_id for d in tasks]}, task_id=task_id, dag_id=dag_run.dag_id, execution_date=dag_run.execution_date, session=session
)
[docs] def skip_all_except( self, ti, branch_task_ids ): """ This method implements the logic for a branching operator; given a single task ID or list of task IDs to follow, this skips all other tasks immediately downstream of this operator. branch_task_ids is stored to XCom so that NotPreviouslySkippedDep knows skipped tasks or newly added tasks should be skipped when they are cleared. """ self.log.info("Following branch %s", branch_task_ids) if isinstance(branch_task_ids, six.string_types): branch_task_ids = [branch_task_ids] dag_run = ti.get_dagrun() task = ti.task dag = task.dag downstream_tasks = task.downstream_list if downstream_tasks: # Also check downstream tasks of the branch task. In case the task to skip # is also a downstream task of the branch task, we exclude it from skipping. branch_downstream_task_ids = set() # type: Set[str] for b in branch_task_ids: branch_downstream_task_ids.update( dag.get_task(b).get_flat_relative_ids(upstream=False) ) skip_tasks = [ t for t in downstream_tasks if t.task_id not in branch_task_ids and t.task_id not in branch_downstream_task_ids ] self.log.info("Skipping tasks %s", [t.task_id for t in skip_tasks]) with create_session() as session: self._set_state_to_skipped( dag_run, ti.execution_date, skip_tasks, session=session ) ti.xcom_push( key=XCOM_SKIPMIXIN_KEY, value={XCOM_SKIPMIXIN_FOLLOWED: branch_task_ids}
)