core.triggers.external_task

Module Contents

Classes

TaskStateTrigger

Base class for all triggers.

DagStateTrigger

Base class for all triggers.
class core.triggers.external_task.TaskStateTrigger(dag_id, task_id, states, execution_dates, poll_interval=5.0)

Bases: airflow.triggers.base.BaseTrigger

Base class for all triggers.

A trigger has two contexts it can exist in:

  • Inside an Operator, when it’s passed to TaskDeferred

  • Actively running in a trigger worker

We use the same class for both situations, and rely on all Trigger classes to be able to return the (Airflow-JSON-encodable) arguments that will let them be re-instantiated elsewhere.

serialize(self)

Serializes TaskStateTrigger arguments and classpath.

async run(self)

Checks periodically in the database to see if the task exists, and has hit one of the states yet, or not.

count_tasks(self, session)

Count how many task instances in the database match our criteria.

class core.triggers.external_task.DagStateTrigger(dag_id, states, execution_dates, poll_interval=5.0)

Bases: airflow.triggers.base.BaseTrigger

Base class for all triggers.

A trigger has two contexts it can exist in:

  • Inside an Operator, when it’s passed to TaskDeferred

  • Actively running in a trigger worker

We use the same class for both situations, and rely on all Trigger classes to be able to return the (Airflow-JSON-encodable) arguments that will let them be re-instantiated elsewhere.

serialize(self)

Serializes DagStateTrigger arguments and classpath.

async run(self)

Checks periodically in the database to see if the dag run exists, and has hit one of the states yet, or not.

count_dags(self, session)

Count how many dag runs in the database match our criteria.