Source code for airflow.providers.amazon.aws.sensors.step_function

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import json
from typing import TYPE_CHECKING, Optional, Sequence

from airflow.exceptions import AirflowException
from airflow.providers.amazon.aws.hooks.step_function import StepFunctionHook
from airflow.sensors.base import BaseSensorOperator

if TYPE_CHECKING:
    from airflow.utils.context import Context


[docs]class StepFunctionExecutionSensor(BaseSensorOperator):
    """
    Asks for the state of the AWS Step Function State Machine Execution until it
    reaches a failure state or success state.
    If it fails, then fail the task.

    On successful completion of the Execution the Sensor will do an XCom Push
    of the State Machine's output to `output`

    .. seealso::
        For more information on how to use this sensor, take a look at the guide:
        :ref:`howto/operator:StepFunctionExecutionSensor`

    :param execution_arn: execution_arn to check the state of
    :param aws_conn_id: aws connection to use, defaults to 'aws_default'
    """

[docs]    INTERMEDIATE_STATES = ('RUNNING',)
[docs]    FAILURE_STATES = (
        'FAILED',
        'TIMED_OUT',
        'ABORTED',
    )
[docs]    SUCCESS_STATES = ('SUCCEEDED',)

[docs]    template_fields: Sequence[str] = ('execution_arn',)
[docs]    template_ext: Sequence[str] = ()
[docs]    ui_color = '#66c3ff'

    def __init__(
        self,
        *,
        execution_arn: str,
        aws_conn_id: str = 'aws_default',
        region_name: Optional[str] = None,
        **kwargs,
    ):
        super().__init__(**kwargs)
        self.execution_arn = execution_arn
        self.aws_conn_id = aws_conn_id
        self.region_name = region_name
        self.hook: Optional[StepFunctionHook] = None

[docs]    def poke(self, context: 'Context'):
        execution_status = self.get_hook().describe_execution(self.execution_arn)
        state = execution_status['status']
        output = json.loads(execution_status['output']) if 'output' in execution_status else None

        if state in self.FAILURE_STATES:
            raise AirflowException(f'Step Function sensor failed. State Machine Output: {output}')

        if state in self.INTERMEDIATE_STATES:
            return False

        self.log.info('Doing xcom_push of output')
        self.xcom_push(context, 'output', output)
        return True

[docs]    def get_hook(self) -> StepFunctionHook:
        """Create and return a StepFunctionHook"""
        if self.hook:
            return self.hook

        self.hook = StepFunctionHook(aws_conn_id=self.aws_conn_id, region_name=self.region_name)
        return self.hook