airflow/providers/apache/livy/sensors/livy.py

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# to you under the Apache License, Version 2.0 (the
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#
#   http://www.apache.org/licenses/LICENSE-2.0
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"""This module contains the Apache Livy sensor."""
from typing import TYPE_CHECKING, Any, Dict, Optional, Sequence, Union

from airflow.providers.apache.livy.hooks.livy import LivyHook
from airflow.sensors.base import BaseSensorOperator

if TYPE_CHECKING:
    from airflow.utils.context import Context


class LivySensor(BaseSensorOperator):
    """
    Monitor a Livy sessions for termination.

    :param livy_conn_id: reference to a pre-defined Livy connection
    :param batch_id: identifier of the monitored batch
        depends on the option that's being modified.
    """

    template_fields: Sequence[str] = ('batch_id',)

    def __init__(
        self,
        *,
        batch_id: Union[int, str],
        livy_conn_id: str = 'livy_default',
        extra_options: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> None:
        super().__init__(**kwargs)
        self.batch_id = batch_id
        self._livy_conn_id = livy_conn_id
        self._livy_hook: Optional[LivyHook] = None
        self._extra_options = extra_options or {}

    def get_hook(self) -> LivyHook:
        """
        Get valid hook.

        :return: hook
        :rtype: LivyHook
        """
        if self._livy_hook is None or not isinstance(self._livy_hook, LivyHook):
            self._livy_hook = LivyHook(livy_conn_id=self._livy_conn_id, extra_options=self._extra_options)
        return self._livy_hook

    def poke(self, context: "Context") -> bool:
        batch_id = self.batch_id

        status = self.get_hook().get_batch_state(batch_id)
        return status in self.get_hook().TERMINAL_STATES