Source code for airflow.models.param

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from __future__ import annotations

import contextlib
import copy
import datetime
import json
import logging
import warnings
from typing import TYPE_CHECKING, Any, ClassVar, ItemsView, Iterable, MutableMapping, ValuesView

from pendulum.parsing import parse_iso8601

from airflow.exceptions import AirflowException, ParamValidationError, RemovedInAirflow3Warning
from airflow.utils import timezone
from airflow.utils.context import Context
from airflow.utils.mixins import ResolveMixin
from airflow.utils.types import NOTSET, ArgNotSet

    from airflow.models.dag import DAG
    from airflow.models.dagrun import DagRun
    from airflow.models.operator import Operator

[docs]logger = logging.getLogger(__name__)
[docs]class Param: """ Class to hold the default value of a Param and rule set to do the validations. Without the rule set it always validates and returns the default value. :param default: The value this Param object holds :param description: Optional help text for the Param :param schema: The validation schema of the Param, if not given then all kwargs except default & description will form the schema """
[docs] __version__: ClassVar[int] = 1
[docs] CLASS_IDENTIFIER = "__class"
def __init__(self, default: Any = NOTSET, description: str | None = None, **kwargs): if default is not NOTSET: self._warn_if_not_json(default) self.value = default self.description = description self.schema = kwargs.pop("schema") if "schema" in kwargs else kwargs
[docs] def __copy__(self) -> Param: return Param(self.value, self.description, schema=self.schema)
@staticmethod def _warn_if_not_json(value): try: json.dumps(value) except Exception: warnings.warn( "The use of non-json-serializable params is deprecated and will be removed in " "a future release", RemovedInAirflow3Warning, ) @staticmethod def _warn_if_not_rfc3339_dt(value): """Fallback to iso8601 datetime validation if rfc3339 failed.""" try: iso8601_value = parse_iso8601(value) except Exception: return None if not isinstance(iso8601_value, datetime.datetime): return None warnings.warn( f"The use of non-RFC3339 datetime: {value!r} is deprecated " "and will be removed in a future release", RemovedInAirflow3Warning, ) if timezone.is_naive(iso8601_value): warnings.warn( "The use naive datetime is deprecated and will be removed in a future release", RemovedInAirflow3Warning, ) return value
[docs] def resolve(self, value: Any = NOTSET, suppress_exception: bool = False) -> Any: """ Runs the validations and returns the Param's final value. May raise ValueError on failed validations, or TypeError if no value is passed and no value already exists. We first check that value is json-serializable; if not, warn. In future release we will require the value to be json-serializable. :param value: The value to be updated for the Param :param suppress_exception: To raise an exception or not when the validations fails. If true and validations fails, the return value would be None. """ import jsonschema from jsonschema import FormatChecker from jsonschema.exceptions import ValidationError if value is not NOTSET: self._warn_if_not_json(value) final_val = value if value is not NOTSET else self.value if isinstance(final_val, ArgNotSet): if suppress_exception: return None raise ParamValidationError("No value passed and Param has no default value") try: jsonschema.validate(final_val, self.schema, format_checker=FormatChecker()) except ValidationError as err: if err.schema.get("format") == "date-time": rfc3339_value = self._warn_if_not_rfc3339_dt(final_val) if rfc3339_value: self.value = rfc3339_value return rfc3339_value if suppress_exception: return None raise ParamValidationError(err) from None self.value = final_val return final_val
[docs] def dump(self) -> dict: """Dump the Param as a dictionary""" out_dict = {self.CLASS_IDENTIFIER: f"{self.__module__}.{self.__class__.__name__}"} out_dict.update(self.__dict__) return out_dict
[docs] def has_value(self) -> bool: return self.value is not NOTSET
[docs] def serialize(self) -> dict: return {"value": self.value, "description": self.description, "schema": self.schema}
[docs] def deserialize(data: dict[str, Any], version: int) -> Param: if version > Param.__version__: raise TypeError("serialized version > class version") return Param(default=data["value"], description=data["description"], schema=data["schema"])
[docs]class ParamsDict(MutableMapping[str, Any]): """ Class to hold all params for dags or tasks. All the keys are strictly string and values are converted into Param's object if they are not already. This class is to replace param's dictionary implicitly and ideally not needed to be used directly. """
[docs] __version__: ClassVar[int] = 1
[docs] __slots__ = ["__dict", "suppress_exception"]
def __init__(self, dict_obj: MutableMapping | None = None, suppress_exception: bool = False): """ :param dict_obj: A dict or dict like object to init ParamsDict :param suppress_exception: Flag to suppress value exceptions while initializing the ParamsDict """ params_dict: dict[str, Param] = {} dict_obj = dict_obj or {} for k, v in dict_obj.items(): if not isinstance(v, Param): params_dict[k] = Param(v) else: params_dict[k] = v self.__dict = params_dict self.suppress_exception = suppress_exception
[docs] def __bool__(self) -> bool: return bool(self.__dict)
[docs] def __eq__(self, other: Any) -> bool: if isinstance(other, ParamsDict): return self.dump() == other.dump() if isinstance(other, dict): return self.dump() == other return NotImplemented
[docs] def __copy__(self) -> ParamsDict: return ParamsDict(self.__dict, self.suppress_exception)
[docs] def __deepcopy__(self, memo: dict[int, Any] | None) -> ParamsDict: return ParamsDict(copy.deepcopy(self.__dict, memo), self.suppress_exception)
[docs] def __contains__(self, o: object) -> bool: return o in self.__dict
[docs] def __len__(self) -> int: return len(self.__dict)
[docs] def __delitem__(self, v: str) -> None: del self.__dict[v]
[docs] def __iter__(self): return iter(self.__dict)
[docs] def __repr__(self): return repr(self.dump())
[docs] def __setitem__(self, key: str, value: Any) -> None: """ Override for dictionary's ``setitem`` method. This method make sure that all values are of Param's type only. :param key: A key which needs to be inserted or updated in the dict :param value: A value which needs to be set against the key. It could be of any type but will be converted and stored as a Param object eventually. """ if isinstance(value, Param): param = value elif key in self.__dict: param = self.__dict[key] try: param.resolve(value=value, suppress_exception=self.suppress_exception) except ParamValidationError as ve: raise ParamValidationError(f"Invalid input for param {key}: {ve}") from None else: # if the key isn't there already and if the value isn't of Param type create a new Param object param = Param(value) self.__dict[key] = param
[docs] def __getitem__(self, key: str) -> Any: """ Override for dictionary's ``getitem`` method. After fetching the key, it would call the resolve method as well on the Param object. :param key: The key to fetch """ param = self.__dict[key] return param.resolve(suppress_exception=self.suppress_exception)
[docs] def get_param(self, key: str) -> Param: """Get the internal :class:`.Param` object for this key""" return self.__dict[key]
[docs] def items(self): return ItemsView(self.__dict)
[docs] def values(self): return ValuesView(self.__dict)
[docs] def update(self, *args, **kwargs) -> None: if len(args) == 1 and not kwargs and isinstance(args[0], ParamsDict): return super().update(args[0].__dict) super().update(*args, **kwargs)
[docs] def dump(self) -> dict[str, Any]: """Dumps the ParamsDict object as a dictionary, while suppressing exceptions""" return {k: v.resolve(suppress_exception=True) for k, v in self.items()}
[docs] def validate(self) -> dict[str, Any]: """Validates & returns all the Params object stored in the dictionary""" resolved_dict = {} try: for k, v in self.items(): resolved_dict[k] = v.resolve(suppress_exception=self.suppress_exception) except ParamValidationError as ve: raise ParamValidationError(f"Invalid input for param {k}: {ve}") from None return resolved_dict
[docs] def serialize(self) -> dict[str, Any]: return self.dump()
[docs] def deserialize(data: dict, version: int) -> ParamsDict: if version > ParamsDict.__version__: raise TypeError("serialized version > class version") return ParamsDict(data)
[docs]class DagParam(ResolveMixin): """DAG run parameter reference. This binds a simple Param object to a name within a DAG instance, so that it can be resolved during the runtime via the ``{{ context }}`` dictionary. The ideal use case of this class is to implicitly convert args passed to a method decorated by ``@dag``. It can be used to parameterize a DAG. You can overwrite its value by setting it on conf when you trigger your DagRun. This can also be used in templates by accessing ``{{ context.params }}``. **Example**: with DAG(...) as dag: EmailOperator(subject=dag.param('subject', 'Hi from Airflow!')) :param current_dag: Dag being used for parameter. :param name: key value which is used to set the parameter :param default: Default value used if no parameter was set. """ def __init__(self, current_dag: DAG, name: str, default: Any = NOTSET): if default is not NOTSET: current_dag.params[name] = default self._name = name self._default = default def iter_references(self) -> Iterable[tuple[Operator, str]]: return ()
[docs] def resolve(self, context: Context) -> Any: """Pull DagParam value from DagRun context. This method is run during ``op.execute()``.""" with contextlib.suppress(KeyError): return context["dag_run"].conf[self._name] if self._default is not NOTSET: return self._default with contextlib.suppress(KeyError): return context["params"][self._name] raise AirflowException(f"No value could be resolved for parameter {self._name}")
[docs]def process_params( dag: DAG, task: Operator, dag_run: DagRun | None, *, suppress_exception: bool, ) -> dict[str, Any]: """Merge, validate params, and convert them into a simple dict.""" from airflow.configuration import conf params = ParamsDict(suppress_exception=suppress_exception) with contextlib.suppress(AttributeError): params.update(dag.params) if task.params: params.update(task.params) if conf.getboolean("core", "dag_run_conf_overrides_params") and dag_run and dag_run.conf: logger.debug("Updating task params (%s) with DagRun.conf (%s)", params, dag_run.conf) params.update(dag_run.conf) return params.validate()

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