Source code for airflow.providers.standard.sensors.python

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from __future__ import annotations

from collections.abc import Mapping, Sequence
from typing import TYPE_CHECKING, Any, Callable

from airflow.sensors.base import BaseSensorOperator, PokeReturnValue
from airflow.utils.context import context_merge
from airflow.utils.operator_helpers import determine_kwargs

if TYPE_CHECKING:
    from airflow.utils.context import Context


[docs]class PythonSensor(BaseSensorOperator):
    """
    Waits for a Python callable to return True.

    User could put input argument in templates_dict
    e.g ``templates_dict = {'start_ds': 1970}``
    and access the argument by calling ``kwargs['templates_dict']['start_ds']``
    in the callable

    :param python_callable: A reference to an object that is callable
    :param op_kwargs: a dictionary of keyword arguments that will get unpacked
        in your function
    :param op_args: a list of positional arguments that will get unpacked when
        calling your callable
    :param templates_dict: a dictionary where the values are templates that
        will get templated by the Airflow engine sometime between
        ``__init__`` and ``execute`` takes place and are made available
        in your callable's context after the template has been applied.

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

[docs]    template_fields: Sequence[str] = ("templates_dict", "op_args", "op_kwargs")

    def __init__(
        self,
        *,
        python_callable: Callable,
        op_args: list | None = None,
        op_kwargs: Mapping[str, Any] | None = None,
        templates_dict: dict | None = None,
        **kwargs,
    ):
        super().__init__(**kwargs)
        self.python_callable = python_callable
        self.op_args = op_args or []
        self.op_kwargs = op_kwargs or {}
        self.templates_dict = templates_dict

[docs]    def poke(self, context: Context) -> PokeReturnValue | bool:
        context_merge(context, self.op_kwargs, templates_dict=self.templates_dict)
        self.op_kwargs = determine_kwargs(self.python_callable, self.op_args, context)

        self.log.info("Poking callable: %s", str(self.python_callable))
        return_value = self.python_callable(*self.op_args, **self.op_kwargs)
        if isinstance(return_value, PokeReturnValue):
            return return_value
        else:
            return PokeReturnValue(bool(return_value))