Source code for airflow.models.baseoperator

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"""Base operator for all operators."""
from __future__ import annotations

import abc
import collections
import contextlib
import copy
import functools
import logging
import sys
import warnings
from abc import ABCMeta, abstractmethod
from datetime import datetime, timedelta
from inspect import signature
from types import ClassMethodDescriptorType, FunctionType
from typing import (

import attr
import pendulum
from dateutil.relativedelta import relativedelta
from sqlalchemy import select
from sqlalchemy.orm import Session
from sqlalchemy.orm.exc import NoResultFound

from airflow.configuration import conf
from airflow.exceptions import (
from airflow.lineage import apply_lineage, prepare_lineage
from airflow.models.abstractoperator import (
from airflow.models.mappedoperator import OperatorPartial, validate_mapping_kwargs
from airflow.models.param import ParamsDict
from airflow.models.pool import Pool
from airflow.models.taskinstance import TaskInstance, clear_task_instances
from airflow.models.taskmixin import DependencyMixin
from airflow.serialization.enums import DagAttributeTypes
from airflow.ti_deps.deps.base_ti_dep import BaseTIDep
from airflow.ti_deps.deps.not_in_retry_period_dep import NotInRetryPeriodDep
from airflow.ti_deps.deps.not_previously_skipped_dep import NotPreviouslySkippedDep
from airflow.ti_deps.deps.prev_dagrun_dep import PrevDagrunDep
from airflow.ti_deps.deps.trigger_rule_dep import TriggerRuleDep
from airflow.triggers.base import BaseTrigger
from airflow.utils import timezone
from airflow.utils.context import Context
from airflow.utils.decorators import fixup_decorator_warning_stack
from airflow.utils.edgemodifier import EdgeModifier
from airflow.utils.helpers import validate_key
from airflow.utils.operator_resources import Resources
from airflow.utils.session import NEW_SESSION, provide_session
from airflow.utils.setup_teardown import SetupTeardownContext
from airflow.utils.trigger_rule import TriggerRule
from airflow.utils.types import NOTSET, ArgNotSet
from airflow.utils.weight_rule import WeightRule
from airflow.utils.xcom import XCOM_RETURN_KEY

    import jinja2  # Slow import.

    from airflow.models.dag import DAG
    from airflow.models.operator import Operator
    from airflow.models.taskinstancekey import TaskInstanceKey
    from airflow.models.xcom_arg import XComArg
    from airflow.utils.task_group import TaskGroup

[docs]ScheduleInterval = Union[str, timedelta, relativedelta]
[docs]TaskPreExecuteHook = Callable[[Context], None]
[docs]TaskPostExecuteHook = Callable[[Context, Any], None]
[docs]T = TypeVar("T", bound=FunctionType)
[docs]logger = logging.getLogger("airflow.models.baseoperator.BaseOperator")
[docs]def parse_retries(retries: Any) -> int | None: if retries is None or isinstance(retries, int): return retries try: parsed_retries = int(retries) except (TypeError, ValueError): raise AirflowException(f"'retries' type must be int, not {type(retries).__name__}") logger.warning("Implicitly converting 'retries' from %r to int", retries) return parsed_retries
[docs]def coerce_timedelta(value: float | timedelta, *, key: str) -> timedelta: if isinstance(value, timedelta): return value logger.debug("%s isn't a timedelta object, assuming secs", key) return timedelta(seconds=value)
[docs]def coerce_resources(resources: dict[str, Any] | None) -> Resources | None: if resources is None: return None return Resources(**resources)
def _get_parent_defaults(dag: DAG | None, task_group: TaskGroup | None) -> tuple[dict, ParamsDict]: if not dag: return {}, ParamsDict() dag_args = copy.copy(dag.default_args) dag_params = copy.deepcopy(dag.params) if task_group: if task_group.default_args and not isinstance(task_group.default_args, raise TypeError("default_args must be a mapping") dag_args.update(task_group.default_args) return dag_args, dag_params
[docs]def get_merged_defaults( dag: DAG | None, task_group: TaskGroup | None, task_params: | None, task_default_args: dict | None, ) -> tuple[dict, ParamsDict]: args, params = _get_parent_defaults(dag, task_group) if task_params: if not isinstance(task_params, raise TypeError("params must be a mapping") params.update(task_params) if task_default_args: if not isinstance(task_default_args, raise TypeError("default_args must be a mapping") args.update(task_default_args) with contextlib.suppress(KeyError): params.update(task_default_args["params"] or {}) return args, params
class _PartialDescriptor: """A descriptor that guards against ``.partial`` being called on Task objects.""" class_method: ClassMethodDescriptorType | None = None def __get__( self, obj: BaseOperator, cls: type[BaseOperator] | None = None ) -> Callable[..., OperatorPartial]: # Call this "partial" so it looks nicer in stack traces. def partial(**kwargs): raise TypeError("partial can only be called on Operator classes, not Tasks themselves") if obj is not None: return partial return self.class_method.__get__(cls, cls) _PARTIAL_DEFAULTS = { "owner": DEFAULT_OWNER, "trigger_rule": DEFAULT_TRIGGER_RULE, "depends_on_past": False, "ignore_first_depends_on_past": DEFAULT_IGNORE_FIRST_DEPENDS_ON_PAST, "wait_for_past_depends_before_skipping": DEFAULT_WAIT_FOR_PAST_DEPENDS_BEFORE_SKIPPING, "wait_for_downstream": False, "retries": DEFAULT_RETRIES, "queue": DEFAULT_QUEUE, "pool_slots": DEFAULT_POOL_SLOTS, "execution_timeout": DEFAULT_TASK_EXECUTION_TIMEOUT, "retry_delay": DEFAULT_RETRY_DELAY, "retry_exponential_backoff": False, "priority_weight": DEFAULT_PRIORITY_WEIGHT, "weight_rule": DEFAULT_WEIGHT_RULE, "inlets": [], "outlets": [], } # This is what handles the actual mapping.
[docs]def partial( operator_class: type[BaseOperator], *, task_id: str, dag: DAG | None = None, task_group: TaskGroup | None = None, start_date: datetime | ArgNotSet = NOTSET, end_date: datetime | ArgNotSet = NOTSET, owner: str | ArgNotSet = NOTSET, email: None | str | Iterable[str] | ArgNotSet = NOTSET, params: | None = None, resources: dict[str, Any] | None | ArgNotSet = NOTSET, trigger_rule: str | ArgNotSet = NOTSET, depends_on_past: bool | ArgNotSet = NOTSET, ignore_first_depends_on_past: bool | ArgNotSet = NOTSET, wait_for_past_depends_before_skipping: bool | ArgNotSet = NOTSET, wait_for_downstream: bool | ArgNotSet = NOTSET, retries: int | None | ArgNotSet = NOTSET, queue: str | ArgNotSet = NOTSET, pool: str | ArgNotSet = NOTSET, pool_slots: int | ArgNotSet = NOTSET, execution_timeout: timedelta | None | ArgNotSet = NOTSET, max_retry_delay: None | timedelta | float | ArgNotSet = NOTSET, retry_delay: timedelta | float | ArgNotSet = NOTSET, retry_exponential_backoff: bool | ArgNotSet = NOTSET, priority_weight: int | ArgNotSet = NOTSET, weight_rule: str | ArgNotSet = NOTSET, sla: timedelta | None | ArgNotSet = NOTSET, max_active_tis_per_dag: int | None | ArgNotSet = NOTSET, max_active_tis_per_dagrun: int | None | ArgNotSet = NOTSET, on_execute_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] | ArgNotSet = NOTSET, on_failure_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] | ArgNotSet = NOTSET, on_success_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] | ArgNotSet = NOTSET, on_retry_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] | ArgNotSet = NOTSET, run_as_user: str | None | ArgNotSet = NOTSET, executor_config: dict | None | ArgNotSet = NOTSET, inlets: Any | None | ArgNotSet = NOTSET, outlets: Any | None | ArgNotSet = NOTSET, doc: str | None | ArgNotSet = NOTSET, doc_md: str | None | ArgNotSet = NOTSET, doc_json: str | None | ArgNotSet = NOTSET, doc_yaml: str | None | ArgNotSet = NOTSET, doc_rst: str | None | ArgNotSet = NOTSET, **kwargs, ) -> OperatorPartial: from airflow.models.dag import DagContext from airflow.utils.task_group import TaskGroupContext validate_mapping_kwargs(operator_class, "partial", kwargs) dag = dag or DagContext.get_current_dag() if dag: task_group = task_group or TaskGroupContext.get_current_task_group(dag) if task_group: task_id = task_group.child_id(task_id) # Merge DAG and task group level defaults into user-supplied values. dag_default_args, partial_params = get_merged_defaults( dag=dag, task_group=task_group, task_params=params, task_default_args=kwargs.pop("default_args", None), ) # Create partial_kwargs from args and kwargs partial_kwargs: dict[str, Any] = { **kwargs, "dag": dag, "task_group": task_group, "task_id": task_id, "start_date": start_date, "end_date": end_date, "owner": owner, "email": email, "trigger_rule": trigger_rule, "depends_on_past": depends_on_past, "ignore_first_depends_on_past": ignore_first_depends_on_past, "wait_for_past_depends_before_skipping": wait_for_past_depends_before_skipping, "wait_for_downstream": wait_for_downstream, "retries": retries, "queue": queue, "pool": pool, "pool_slots": pool_slots, "execution_timeout": execution_timeout, "max_retry_delay": max_retry_delay, "retry_delay": retry_delay, "retry_exponential_backoff": retry_exponential_backoff, "priority_weight": priority_weight, "weight_rule": weight_rule, "sla": sla, "max_active_tis_per_dag": max_active_tis_per_dag, "max_active_tis_per_dagrun": max_active_tis_per_dagrun, "on_execute_callback": on_execute_callback, "on_failure_callback": on_failure_callback, "on_retry_callback": on_retry_callback, "on_success_callback": on_success_callback, "run_as_user": run_as_user, "executor_config": executor_config, "inlets": inlets, "outlets": outlets, "resources": resources, "doc": doc, "doc_json": doc_json, "doc_md": doc_md, "doc_rst": doc_rst, "doc_yaml": doc_yaml, } # Inject DAG-level default args into args provided to this function. partial_kwargs.update((k, v) for k, v in dag_default_args.items() if partial_kwargs.get(k) is NOTSET) # Fill fields not provided by the user with default values. partial_kwargs = {k: _PARTIAL_DEFAULTS.get(k) if v is NOTSET else v for k, v in partial_kwargs.items()} # Post-process arguments. Should be kept in sync with _TaskDecorator.expand(). if "task_concurrency" in kwargs: # Reject deprecated option. raise TypeError("unexpected argument: task_concurrency") if partial_kwargs["wait_for_downstream"]: partial_kwargs["depends_on_past"] = True partial_kwargs["start_date"] = timezone.convert_to_utc(partial_kwargs["start_date"]) partial_kwargs["end_date"] = timezone.convert_to_utc(partial_kwargs["end_date"]) if partial_kwargs["pool"] is None: partial_kwargs["pool"] = Pool.DEFAULT_POOL_NAME partial_kwargs["retries"] = parse_retries(partial_kwargs["retries"]) partial_kwargs["retry_delay"] = coerce_timedelta(partial_kwargs["retry_delay"], key="retry_delay") if partial_kwargs["max_retry_delay"] is not None: partial_kwargs["max_retry_delay"] = coerce_timedelta( partial_kwargs["max_retry_delay"], key="max_retry_delay", ) partial_kwargs["executor_config"] = partial_kwargs["executor_config"] or {} partial_kwargs["resources"] = coerce_resources(partial_kwargs["resources"]) return OperatorPartial( operator_class=operator_class, kwargs=partial_kwargs, params=partial_params, )
[docs]class BaseOperatorMeta(abc.ABCMeta): """Metaclass of BaseOperator.""" @classmethod def _apply_defaults(cls, func: T) -> T: """ Look for an argument named "default_args", and fill the unspecified arguments from it. Since python2.* isn't clear about which arguments are missing when calling a function, and that this can be quite confusing with multi-level inheritance and argument defaults, this decorator also alerts with specific information about the missing arguments. """ # Cache inspect.signature for the wrapper closure to avoid calling it # at every decorated invocation. This is separate sig_cache created # per decoration, i.e. each function decorated using apply_defaults will # have a different sig_cache. sig_cache = signature(func) non_variadic_params = { name: param for (name, param) in sig_cache.parameters.items() if != "self" and param.kind not in (param.VAR_POSITIONAL, param.VAR_KEYWORD) } non_optional_args = { name for name, param in non_variadic_params.items() if param.default == param.empty and name != "task_id" } fixup_decorator_warning_stack(func) @functools.wraps(func) def apply_defaults(self: BaseOperator, *args: Any, **kwargs: Any) -> Any: from airflow.models.dag import DagContext from airflow.utils.task_group import TaskGroupContext if len(args) > 0: raise AirflowException("Use keyword arguments when initializing operators") instantiated_from_mapped = kwargs.pop( "_airflow_from_mapped", getattr(self, "_BaseOperator__from_mapped", False), ) dag: DAG | None = kwargs.get("dag") or DagContext.get_current_dag() task_group: TaskGroup | None = kwargs.get("task_group") if dag and not task_group: task_group = TaskGroupContext.get_current_task_group(dag) default_args, merged_params = get_merged_defaults( dag=dag, task_group=task_group, task_params=kwargs.pop("params", None), task_default_args=kwargs.pop("default_args", None), ) for arg in sig_cache.parameters: if arg not in kwargs and arg in default_args: kwargs[arg] = default_args[arg] missing_args = non_optional_args.difference(kwargs) if len(missing_args) == 1: raise AirflowException(f"missing keyword argument {missing_args.pop()!r}") elif missing_args: display = ", ".join(repr(a) for a in sorted(missing_args)) raise AirflowException(f"missing keyword arguments {display}") if merged_params: kwargs["params"] = merged_params hook = getattr(self, "_hook_apply_defaults", None) if hook: args, kwargs = hook(**kwargs, default_args=default_args) default_args = kwargs.pop("default_args", {}) if not hasattr(self, "_BaseOperator__init_kwargs"): self._BaseOperator__init_kwargs = {} self._BaseOperator__from_mapped = instantiated_from_mapped result = func(self, **kwargs, default_args=default_args) # Store the args passed to init -- we need them to support serialzation! self._BaseOperator__init_kwargs.update(kwargs) # type: ignore # Set upstream task defined by XComArgs passed to template fields of the operator. # BUT: only do this _ONCE_, not once for each class in the hierarchy if not instantiated_from_mapped and func == self.__init__.__wrapped__: # type: ignore[misc] self.set_xcomargs_dependencies() # Mark instance as instantiated. self._BaseOperator__instantiated = True return result apply_defaults.__non_optional_args = non_optional_args # type: ignore apply_defaults.__param_names = set(non_variadic_params) # type: ignore return cast(T, apply_defaults) def __new__(cls, name, bases, namespace, **kwargs): new_cls = super().__new__(cls, name, bases, namespace, **kwargs) with contextlib.suppress(KeyError): # Update the partial descriptor with the class method, so it calls the actual function # (but let subclasses override it if they need to) partial_desc = vars(new_cls)["partial"] if isinstance(partial_desc, _PartialDescriptor): partial_desc.class_method = classmethod(partial) new_cls.__init__ = cls._apply_defaults(new_cls.__init__) return new_cls
[docs]class BaseOperator(AbstractOperator, metaclass=BaseOperatorMeta): """ Abstract base class for all operators. Since operators create objects that become nodes in the DAG, BaseOperator contains many recursive methods for DAG crawling behavior. To derive from this class, you are expected to override the constructor and the 'execute' method. Operators derived from this class should perform or trigger certain tasks synchronously (wait for completion). Example of operators could be an operator that runs a Pig job (PigOperator), a sensor operator that waits for a partition to land in Hive (HiveSensorOperator), or one that moves data from Hive to MySQL (Hive2MySqlOperator). Instances of these operators (tasks) target specific operations, running specific scripts, functions or data transfers. This class is abstract and shouldn't be instantiated. Instantiating a class derived from this one results in the creation of a task object, which ultimately becomes a node in DAG objects. Task dependencies should be set by using the set_upstream and/or set_downstream methods. :param task_id: a unique, meaningful id for the task :param owner: the owner of the task. Using a meaningful description (e.g. user/person/team/role name) to clarify ownership is recommended. :param email: the 'to' email address(es) used in email alerts. This can be a single email or multiple ones. Multiple addresses can be specified as a comma or semicolon separated string or by passing a list of strings. :param email_on_retry: Indicates whether email alerts should be sent when a task is retried :param email_on_failure: Indicates whether email alerts should be sent when a task failed :param retries: the number of retries that should be performed before failing the task :param retry_delay: delay between retries, can be set as ``timedelta`` or ``float`` seconds, which will be converted into ``timedelta``, the default is ``timedelta(seconds=300)``. :param retry_exponential_backoff: allow progressively longer waits between retries by using exponential backoff algorithm on retry delay (delay will be converted into seconds) :param max_retry_delay: maximum delay interval between retries, can be set as ``timedelta`` or ``float`` seconds, which will be converted into ``timedelta``. :param start_date: The ``start_date`` for the task, determines the ``execution_date`` for the first task instance. The best practice is to have the start_date rounded to your DAG's ``schedule_interval``. Daily jobs have their start_date some day at 00:00:00, hourly jobs have their start_date at 00:00 of a specific hour. Note that Airflow simply looks at the latest ``execution_date`` and adds the ``schedule_interval`` to determine the next ``execution_date``. It is also very important to note that different tasks' dependencies need to line up in time. If task A depends on task B and their start_date are offset in a way that their execution_date don't line up, A's dependencies will never be met. If you are looking to delay a task, for example running a daily task at 2AM, look into the ``TimeSensor`` and ``TimeDeltaSensor``. We advise against using dynamic ``start_date`` and recommend using fixed ones. Read the FAQ entry about start_date for more information. :param end_date: if specified, the scheduler won't go beyond this date :param depends_on_past: when set to true, task instances will run sequentially and only if the previous instance has succeeded or has been skipped. The task instance for the start_date is allowed to run. :param wait_for_past_depends_before_skipping: when set to true, if the task instance should be marked as skipped, and depends_on_past is true, the ti will stay on None state waiting the task of the previous run :param wait_for_downstream: when set to true, an instance of task X will wait for tasks immediately downstream of the previous instance of task X to finish successfully or be skipped before it runs. This is useful if the different instances of a task X alter the same asset, and this asset is used by tasks downstream of task X. Note that depends_on_past is forced to True wherever wait_for_downstream is used. Also note that only tasks *immediately* downstream of the previous task instance are waited for; the statuses of any tasks further downstream are ignored. :param dag: a reference to the dag the task is attached to (if any) :param priority_weight: priority weight of this task against other task. This allows the executor to trigger higher priority tasks before others when things get backed up. Set priority_weight as a higher number for more important tasks. :param weight_rule: weighting method used for the effective total priority weight of the task. Options are: ``{ downstream | upstream | absolute }`` default is ``downstream`` When set to ``downstream`` the effective weight of the task is the aggregate sum of all downstream descendants. As a result, upstream tasks will have higher weight and will be scheduled more aggressively when using positive weight values. This is useful when you have multiple dag run instances and desire to have all upstream tasks to complete for all runs before each dag can continue processing downstream tasks. When set to ``upstream`` the effective weight is the aggregate sum of all upstream ancestors. This is the opposite where downstream tasks have higher weight and will be scheduled more aggressively when using positive weight values. This is useful when you have multiple dag run instances and prefer to have each dag complete before starting upstream tasks of other dags. When set to ``absolute``, the effective weight is the exact ``priority_weight`` specified without additional weighting. You may want to do this when you know exactly what priority weight each task should have. Additionally, when set to ``absolute``, there is bonus effect of significantly speeding up the task creation process as for very large DAGs. Options can be set as string or using the constants defined in the static class ``airflow.utils.WeightRule`` :param queue: which queue to target when running this job. Not all executors implement queue management, the CeleryExecutor does support targeting specific queues. :param pool: the slot pool this task should run in, slot pools are a way to limit concurrency for certain tasks :param pool_slots: the number of pool slots this task should use (>= 1) Values less than 1 are not allowed. :param sla: time by which the job is expected to succeed. Note that this represents the ``timedelta`` after the period is closed. For example if you set an SLA of 1 hour, the scheduler would send an email soon after 1:00AM on the ``2016-01-02`` if the ``2016-01-01`` instance has not succeeded yet. The scheduler pays special attention for jobs with an SLA and sends alert emails for SLA misses. SLA misses are also recorded in the database for future reference. All tasks that share the same SLA time get bundled in a single email, sent soon after that time. SLA notification are sent once and only once for each task instance. :param execution_timeout: max time allowed for the execution of this task instance, if it goes beyond it will raise and fail. :param on_failure_callback: a function or list of functions to be called when a task instance of this task fails. a context dictionary is passed as a single parameter to this function. Context contains references to related objects to the task instance and is documented under the macros section of the API. :param on_execute_callback: much like the ``on_failure_callback`` except that it is executed right before the task is executed. :param on_retry_callback: much like the ``on_failure_callback`` except that it is executed when retries occur. :param on_success_callback: much like the ``on_failure_callback`` except that it is executed when the task succeeds. :param pre_execute: a function to be called immediately before task execution, receiving a context dictionary; raising an exception will prevent the task from being executed. |experimental| :param post_execute: a function to be called immediately after task execution, receiving a context dictionary and task result; raising an exception will prevent the task from succeeding. |experimental| :param trigger_rule: defines the rule by which dependencies are applied for the task to get triggered. Options are: ``{ all_success | all_failed | all_done | all_skipped | one_success | one_done | one_failed | none_failed | none_failed_min_one_success | none_skipped | always}`` default is ``all_success``. Options can be set as string or using the constants defined in the static class ``airflow.utils.TriggerRule`` :param resources: A map of resource parameter names (the argument names of the Resources constructor) to their values. :param run_as_user: unix username to impersonate while running the task :param max_active_tis_per_dag: When set, a task will be able to limit the concurrent runs across execution_dates. :param max_active_tis_per_dagrun: When set, a task will be able to limit the concurrent task instances per DAG run. :param executor_config: Additional task-level configuration parameters that are interpreted by a specific executor. Parameters are namespaced by the name of executor. **Example**: to run this task in a specific docker container through the KubernetesExecutor :: MyOperator(..., executor_config={ "KubernetesExecutor": {"image": "myCustomDockerImage"} } ) :param do_xcom_push: if True, an XCom is pushed containing the Operator's result :param task_group: The TaskGroup to which the task should belong. This is typically provided when not using a TaskGroup as a context manager. :param doc: Add documentation or notes to your Task objects that is visible in Task Instance details View in the Webserver :param doc_md: Add documentation (in Markdown format) or notes to your Task objects that is visible in Task Instance details View in the Webserver :param doc_rst: Add documentation (in RST format) or notes to your Task objects that is visible in Task Instance details View in the Webserver :param doc_json: Add documentation (in JSON format) or notes to your Task objects that is visible in Task Instance details View in the Webserver :param doc_yaml: Add documentation (in YAML format) or notes to your Task objects that is visible in Task Instance details View in the Webserver """ # Implementing Operator.
[docs] template_fields: Sequence[str] = ()
[docs] template_ext: Sequence[str] = ()
[docs] template_fields_renderers: dict[str, str] = {}
# Defines the color in the UI
[docs] ui_color: str = "#fff"
[docs] ui_fgcolor: str = "#000"
[docs] pool: str = ""
# base list which includes all the attrs that don't need deep copy. _base_operator_shallow_copy_attrs: tuple[str, ...] = ( "user_defined_macros", "user_defined_filters", "params", "_log", ) # each operator should override this class attr for shallow copy attrs.
[docs] shallow_copy_attrs: Sequence[str] = ()
# Defines the operator level extra links # The _serialized_fields are lazily loaded when get_serialized_fields() method is called __serialized_fields: frozenset[str] | None = None
[docs] partial: Callable[..., OperatorPartial] = _PartialDescriptor() # type: ignore
_comps = { "task_id", "dag_id", "owner", "email", "email_on_retry", "retry_delay", "retry_exponential_backoff", "max_retry_delay", "start_date", "end_date", "depends_on_past", "wait_for_downstream", "priority_weight", "sla", "execution_timeout", "on_execute_callback", "on_failure_callback", "on_success_callback", "on_retry_callback", "do_xcom_push", } # Defines if the operator supports lineage without manual definitions
[docs] supports_lineage = False
# If True then the class constructor was called __instantiated = False # List of args as passed to `init()`, after apply_defaults() has been updated. Used to "recreate" the task # when mapping __init_kwargs: dict[str, Any] # Set to True before calling execute method _lock_for_execution = False _dag: DAG | None = None
[docs] task_group: TaskGroup | None = None
# subdag parameter is only set for SubDagOperator. # Setting it to None by default as other Operators do not have that field
[docs] subdag: DAG | None = None
[docs] start_date: pendulum.DateTime | None = None
[docs] end_date: pendulum.DateTime | None = None
# Set to True for an operator instantiated by a mapped operator. __from_mapped = False def __init__( self, task_id: str, owner: str = DEFAULT_OWNER, email: str | Iterable[str] | None = None, email_on_retry: bool = conf.getboolean("email", "default_email_on_retry", fallback=True), email_on_failure: bool = conf.getboolean("email", "default_email_on_failure", fallback=True), retries: int | None = DEFAULT_RETRIES, retry_delay: timedelta | float = DEFAULT_RETRY_DELAY, retry_exponential_backoff: bool = False, max_retry_delay: timedelta | float | None = None, start_date: datetime | None = None, end_date: datetime | None = None, depends_on_past: bool = False, ignore_first_depends_on_past: bool = DEFAULT_IGNORE_FIRST_DEPENDS_ON_PAST, wait_for_past_depends_before_skipping: bool = DEFAULT_WAIT_FOR_PAST_DEPENDS_BEFORE_SKIPPING, wait_for_downstream: bool = False, dag: DAG | None = None, params: | None = None, default_args: dict | None = None, priority_weight: int = DEFAULT_PRIORITY_WEIGHT, weight_rule: str = DEFAULT_WEIGHT_RULE, queue: str = DEFAULT_QUEUE, pool: str | None = None, pool_slots: int = DEFAULT_POOL_SLOTS, sla: timedelta | None = None, execution_timeout: timedelta | None = DEFAULT_TASK_EXECUTION_TIMEOUT, on_execute_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] = None, on_failure_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] = None, on_success_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] = None, on_retry_callback: None | TaskStateChangeCallback | list[TaskStateChangeCallback] = None, pre_execute: TaskPreExecuteHook | None = None, post_execute: TaskPostExecuteHook | None = None, trigger_rule: str = DEFAULT_TRIGGER_RULE, resources: dict[str, Any] | None = None, run_as_user: str | None = None, task_concurrency: int | None = None, max_active_tis_per_dag: int | None = None, max_active_tis_per_dagrun: int | None = None, executor_config: dict | None = None, do_xcom_push: bool = True, inlets: Any | None = None, outlets: Any | None = None, task_group: TaskGroup | None = None, doc: str | None = None, doc_md: str | None = None, doc_json: str | None = None, doc_yaml: str | None = None, doc_rst: str | None = None, **kwargs, ): from airflow.models.dag import DagContext from airflow.utils.task_group import TaskGroupContext self.__init_kwargs = {} super().__init__() kwargs.pop("_airflow_mapped_validation_only", None) if kwargs: if not conf.getboolean("operators", "ALLOW_ILLEGAL_ARGUMENTS"): raise AirflowException( f"Invalid arguments were passed to {self.__class__.__name__} (task_id: {task_id}). " f"Invalid arguments were:\n**kwargs: {kwargs}", ) warnings.warn( f"Invalid arguments were passed to {self.__class__.__name__} (task_id: {task_id}). " "Support for passing such arguments will be dropped in future. " f"Invalid arguments were:\n**kwargs: {kwargs}", category=RemovedInAirflow3Warning, stacklevel=3, ) validate_key(task_id) dag = dag or DagContext.get_current_dag() task_group = task_group or TaskGroupContext.get_current_task_group(dag) self.task_id = task_group.child_id(task_id) if task_group else task_id if not self.__from_mapped and task_group: task_group.add(self) self.owner = owner = email self.email_on_retry = email_on_retry self.email_on_failure = email_on_failure if execution_timeout is not None and not isinstance(execution_timeout, timedelta): raise ValueError( f"execution_timeout must be timedelta object but passed as type: {type(execution_timeout)}" ) self.execution_timeout = execution_timeout self.on_execute_callback = on_execute_callback self.on_failure_callback = on_failure_callback self.on_success_callback = on_success_callback self.on_retry_callback = on_retry_callback self._pre_execute_hook = pre_execute self._post_execute_hook = post_execute if start_date and not isinstance(start_date, datetime): self.log.warning("start_date for %s isn't datetime.datetime", self) elif start_date: self.start_date = timezone.convert_to_utc(start_date) if end_date: self.end_date = timezone.convert_to_utc(end_date) self.executor_config = executor_config or {} self.run_as_user = run_as_user self.retries = parse_retries(retries) self.queue = queue self.pool = Pool.DEFAULT_POOL_NAME if pool is None else pool self.pool_slots = pool_slots if self.pool_slots < 1: dag_str = f" in dag {dag.dag_id}" if dag else "" raise ValueError(f"pool slots for {self.task_id}{dag_str} cannot be less than 1") self.sla = sla if trigger_rule == "dummy": warnings.warn( "dummy Trigger Rule is deprecated. Please use `TriggerRule.ALWAYS`.", RemovedInAirflow3Warning, stacklevel=2, ) trigger_rule = TriggerRule.ALWAYS if trigger_rule == "none_failed_or_skipped": warnings.warn( "none_failed_or_skipped Trigger Rule is deprecated. " "Please use `none_failed_min_one_success`.", RemovedInAirflow3Warning, stacklevel=2, ) trigger_rule = TriggerRule.NONE_FAILED_MIN_ONE_SUCCESS if not TriggerRule.is_valid(trigger_rule): raise AirflowException( f"The trigger_rule must be one of {TriggerRule.all_triggers()}," f"'{dag.dag_id if dag else ''}.{task_id}'; received '{trigger_rule}'." ) self.trigger_rule: TriggerRule = TriggerRule(trigger_rule) FailStopDagInvalidTriggerRule.check(dag=dag, trigger_rule=self.trigger_rule) self.depends_on_past: bool = depends_on_past self.ignore_first_depends_on_past: bool = ignore_first_depends_on_past self.wait_for_past_depends_before_skipping: bool = wait_for_past_depends_before_skipping self.wait_for_downstream: bool = wait_for_downstream if wait_for_downstream: self.depends_on_past = True self.retry_delay = coerce_timedelta(retry_delay, key="retry_delay") self.retry_exponential_backoff = retry_exponential_backoff self.max_retry_delay = ( max_retry_delay if max_retry_delay is None else coerce_timedelta(max_retry_delay, key="max_retry_delay") ) # At execution_time this becomes a normal dict self.params: ParamsDict | dict = ParamsDict(params) if priority_weight is not None and not isinstance(priority_weight, int): raise AirflowException( f"`priority_weight` for task '{self.task_id}' only accepts integers, " f"received '{type(priority_weight)}'." ) self.priority_weight = priority_weight if not WeightRule.is_valid(weight_rule): raise AirflowException( f"The weight_rule must be one of " f"{WeightRule.all_weight_rules},'{dag.dag_id if dag else ''}.{task_id}'; " f"received '{weight_rule}'." ) self.weight_rule = weight_rule self.resources = coerce_resources(resources) if task_concurrency and not max_active_tis_per_dag: # TODO: Remove in Airflow 3.0 warnings.warn( "The 'task_concurrency' parameter is deprecated. Please use 'max_active_tis_per_dag'.", RemovedInAirflow3Warning, stacklevel=2, ) max_active_tis_per_dag = task_concurrency self.max_active_tis_per_dag: int | None = max_active_tis_per_dag self.max_active_tis_per_dagrun: int | None = max_active_tis_per_dagrun self.do_xcom_push = do_xcom_push self.doc_md = doc_md self.doc_json = doc_json self.doc_yaml = doc_yaml self.doc_rst = doc_rst self.doc = doc self.upstream_task_ids: set[str] = set() self.downstream_task_ids: set[str] = set() if dag: self.dag = dag self._log = logging.getLogger("airflow.task.operators") # Lineage self.inlets: list = [] self.outlets: list = [] if inlets: self.inlets = ( inlets if isinstance(inlets, list) else [ inlets, ] ) if outlets: self.outlets = ( outlets if isinstance(outlets, list) else [ outlets, ] ) if isinstance(self.template_fields, str): warnings.warn( f"The `template_fields` value for {self.task_type} is a string " "but should be a list or tuple of string. Wrapping it in a list for execution. " f"Please update {self.task_type} accordingly.", UserWarning, stacklevel=2, ) self.template_fields = [self.template_fields] self._is_setup = False self._is_teardown = False if SetupTeardownContext.update_context_map(self)
[docs] def __eq__(self, other): if type(self) is type(other): # Use getattr() instead of __dict__ as __dict__ doesn't return # correct values for properties. return all(getattr(self, c, None) == getattr(other, c, None) for c in self._comps) return False
[docs] def __ne__(self, other): return not self == other
[docs] def __hash__(self): hash_components = [type(self)] for component in self._comps: val = getattr(self, component, None) try: hash(val) hash_components.append(val) except TypeError: hash_components.append(repr(val)) return hash(tuple(hash_components))
# including lineage information
[docs] def __or__(self, other): """ Called for [This Operator] | [Operator]. The inlets of other will be set to pick up the outlets from this operator. Other will be set as a downstream task of this operator. """ if isinstance(other, BaseOperator): if not self.outlets and not self.supports_lineage: raise ValueError("No outlets defined for this operator") other.add_inlets([self.task_id]) self.set_downstream(other) else: raise TypeError(f"Right hand side ({other}) is not an Operator") return self
# /Composing Operators ---------------------------------------------
[docs] def __gt__(self, other): """ Called for [Operator] > [Outlet]. If other is an attr annotated object it is set as an outlet of this Operator. """ if not isinstance(other, Iterable): other = [other] for obj in other: if not attr.has(obj): raise TypeError(f"Left hand side ({obj}) is not an outlet") self.add_outlets(other) return self
[docs] def __lt__(self, other): """ Called for [Inlet] > [Operator] or [Operator] < [Inlet]. If other is an attr annotated object it is set as an inlet to this operator. """ if not isinstance(other, Iterable): other = [other] for obj in other: if not attr.has(obj): raise TypeError(f"{obj} cannot be an inlet") self.add_inlets(other) return self
[docs] def __setattr__(self, key, value): super().__setattr__(key, value) if self.__from_mapped or self._lock_for_execution: return # Skip any custom behavior for validation and during execute. if key in self.__init_kwargs: self.__init_kwargs[key] = value if self.__instantiated and key in self.template_fields: # Resolve upstreams set by assigning an XComArg after initializing # an operator, example: # op = BashOperator() # op.bash_command = "sleep 1" self.set_xcomargs_dependencies()
[docs] def add_inlets(self, inlets: Iterable[Any]): """Sets inlets to this operator.""" self.inlets.extend(inlets)
[docs] def add_outlets(self, outlets: Iterable[Any]): """Defines the outlets of this operator.""" self.outlets.extend(outlets)
def get_inlet_defs(self): """Gets inlet definitions on this task. :meta private: """ return self.inlets def get_outlet_defs(self): """Gets outlet definitions on this task. :meta private: """ return self.outlets
[docs] def get_dag(self) -> DAG | None: return self._dag
@property # type: ignore[override]
[docs] def dag(self) -> DAG: # type: ignore[override] """Returns the Operator's DAG if set, otherwise raises an error.""" if self._dag: return self._dag else: raise AirflowException(f"Operator {self} has not been assigned to a DAG yet")
@dag.setter def dag(self, dag: DAG | None): """Operators can be assigned to one DAG, one time. Repeat assignments to that same DAG are ok.""" from airflow.models.dag import DAG if dag is None: self._dag = None return if not isinstance(dag, DAG): raise TypeError(f"Expected DAG; received {dag.__class__.__name__}") elif self.has_dag() and self.dag is not dag: raise AirflowException(f"The DAG assigned to {self} can not be changed.") if self.__from_mapped: pass # Don't add to DAG -- the mapped task takes the place. elif self.task_id not in dag.task_dict: dag.add_task(self) elif self.task_id in dag.task_dict and dag.task_dict[self.task_id] is not self: dag.add_task(self) self._dag = dag
[docs] def has_dag(self): """Returns True if the Operator has been assigned to a DAG.""" return self._dag is not None
[docs] deps: frozenset[BaseTIDep] = frozenset( { NotInRetryPeriodDep(), PrevDagrunDep(), TriggerRuleDep(), NotPreviouslySkippedDep(), } )
""" Returns the set of dependencies for the operator. These differ from execution context dependencies in that they are specific to tasks and can be extended/overridden by subclasses. """
[docs] def prepare_for_execution(self) -> BaseOperator: """Lock task for execution to disable custom action in ``__setattr__`` and return a copy.""" other = copy.copy(self) other._lock_for_execution = True return other
[docs] def set_xcomargs_dependencies(self) -> None: """ Resolves upstream dependencies of a task. In this way passing an ``XComArg`` as value for a template field will result in creating upstream relation between two tasks. **Example**: :: with DAG(...): generate_content = GenerateContentOperator(task_id="generate_content") send_email = EmailOperator(..., html_content=generate_content.output) # This is equivalent to with DAG(...): generate_content = GenerateContentOperator(task_id="generate_content") send_email = EmailOperator( ..., html_content="{{ task_instance.xcom_pull('generate_content') }}" ) generate_content >> send_email """ from airflow.models.xcom_arg import XComArg for field in self.template_fields: if hasattr(self, field): arg = getattr(self, field) XComArg.apply_upstream_relationship(self, arg)
[docs] def pre_execute(self, context: Any): """This hook is triggered right before self.execute() is called.""" if self._pre_execute_hook is not None: self._pre_execute_hook(context)
[docs] def execute(self, context: Context) -> Any: """ This is the main method to derive when creating an operator. Context is the same dictionary used as when rendering jinja templates. Refer to get_template_context for more context. """ raise NotImplementedError()
[docs] def post_execute(self, context: Any, result: Any = None): """ This hook is triggered right after self.execute() is called. It is passed the execution context and any results returned by the operator. """ if self._post_execute_hook is not None: self._post_execute_hook(context, result)
[docs] def on_kill(self) -> None: """ Override this method to clean up subprocesses when a task instance gets killed. Any use of the threading, subprocess or multiprocessing module within an operator needs to be cleaned up, or it will leave ghost processes behind. """
[docs] def __deepcopy__(self, memo): # Hack sorting double chained task lists by task_id to avoid hitting # max_depth on deepcopy operations. sys.setrecursionlimit(5000) # TODO fix this in a better way cls = self.__class__ result = cls.__new__(cls) memo[id(self)] = result shallow_copy = cls.shallow_copy_attrs + cls._base_operator_shallow_copy_attrs for k, v in self.__dict__.items(): if k == "_BaseOperator__instantiated": # Don't set this until the _end_, as it changes behaviour of __setattr__ continue if k not in shallow_copy: setattr(result, k, copy.deepcopy(v, memo)) else: setattr(result, k, copy.copy(v)) result.__instantiated = self.__instantiated return result
[docs] def __getstate__(self): state = dict(self.__dict__) del state["_log"] return state
[docs] def __setstate__(self, state): self.__dict__ = state self._log = logging.getLogger("airflow.task.operators")
[docs] def render_template_fields( self, context: Context, jinja_env: jinja2.Environment | None = None, ) -> None: """Template all attributes listed in *self.template_fields*. This mutates the attributes in-place and is irreversible. :param context: Context dict with values to apply on content. :param jinja_env: Jinja's environment to use for rendering. """ if not jinja_env: jinja_env = self.get_template_env() self._do_render_template_fields(self, self.template_fields, context, jinja_env, set())
[docs] def clear( self, start_date: datetime | None = None, end_date: datetime | None = None, upstream: bool = False, downstream: bool = False, session: Session = NEW_SESSION, ): """Clears the state of task instances associated with the task, following the parameters specified.""" qry = select(TaskInstance).where(TaskInstance.dag_id == self.dag_id) if start_date: qry = qry.where(TaskInstance.execution_date >= start_date) if end_date: qry = qry.where(TaskInstance.execution_date <= end_date) tasks = [self.task_id] if upstream: tasks += [t.task_id for t in self.get_flat_relatives(upstream=True)] if downstream: tasks += [t.task_id for t in self.get_flat_relatives(upstream=False)] qry = qry.where(TaskInstance.task_id.in_(tasks)) results = session.scalars(qry).all() count = len(results) clear_task_instances(results, session, dag=self.dag) session.commit() return count
[docs] def get_task_instances( self, start_date: datetime | None = None, end_date: datetime | None = None, session: Session = NEW_SESSION, ) -> list[TaskInstance]: """Get task instances related to this task for a specific date range.""" from airflow.models import DagRun query = ( select(TaskInstance) .join(TaskInstance.dag_run) .where(TaskInstance.dag_id == self.dag_id) .where(TaskInstance.task_id == self.task_id) ) if start_date: query = query.where(DagRun.execution_date >= start_date) if end_date: query = query.where(DagRun.execution_date <= end_date) return session.scalars(query.order_by(DagRun.execution_date)).all()
[docs] def run( self, start_date: datetime | None = None, end_date: datetime | None = None, ignore_first_depends_on_past: bool = True, wait_for_past_depends_before_skipping: bool = False, ignore_ti_state: bool = False, mark_success: bool = False, test_mode: bool = False, session: Session = NEW_SESSION, ) -> None: """Run a set of task instances for a date range.""" from airflow.models import DagRun from airflow.utils.types import DagRunType # Assertions for typing -- we need a dag, for this function, and when we have a DAG we are # _guaranteed_ to have start_date (else we couldn't have been added to a DAG) if TYPE_CHECKING: assert self.start_date start_date = pendulum.instance(start_date or self.start_date) end_date = pendulum.instance(end_date or self.end_date or timezone.utcnow()) for info in self.dag.iter_dagrun_infos_between(start_date, end_date, align=False): ignore_depends_on_past = info.logical_date == start_date and ignore_first_depends_on_past try: dag_run = session.scalars( select(DagRun).where( DagRun.dag_id == self.dag_id, DagRun.execution_date == info.logical_date, ) ).one() ti = TaskInstance(self, run_id=dag_run.run_id) except NoResultFound: # This is _mostly_ only used in tests dr = DagRun( dag_id=self.dag_id, run_id=DagRun.generate_run_id(DagRunType.MANUAL, info.logical_date), run_type=DagRunType.MANUAL, execution_date=info.logical_date, data_interval=info.data_interval, ) ti = TaskInstance(self, run_id=dr.run_id) ti.dag_run = dr session.add(dr) session.flush() mark_success=mark_success, ignore_depends_on_past=ignore_depends_on_past, wait_for_past_depends_before_skipping=wait_for_past_depends_before_skipping, ignore_ti_state=ignore_ti_state, test_mode=test_mode, session=session, )
[docs] def dry_run(self) -> None: """Performs dry run for the operator - just render template fields.""""Dry run") for field in self.template_fields: try: content = getattr(self, field) except AttributeError: raise AttributeError( f"{field!r} is configured as a template field " f"but {self.task_type} does not have this attribute." ) if content and isinstance(content, str):"Rendering template for %s", field)
[docs] def get_direct_relatives(self, upstream: bool = False) -> Iterable[Operator]: """Get list of the direct relatives to the current task, upstream or downstream.""" if upstream: return self.upstream_list else: return self.downstream_list
[docs] def __repr__(self): return "<Task({self.task_type}): {self.task_id}>".format(self=self)
[docs] def operator_class(self) -> type[BaseOperator]: # type: ignore[override] return self.__class__
[docs] def task_type(self) -> str: """@property: type of the task.""" return self.__class__.__name__
[docs] def operator_name(self) -> str: """@property: use a more friendly display name for the operator, if set.""" try: return self.custom_operator_name # type: ignore except AttributeError: return self.task_type
[docs] def roots(self) -> list[BaseOperator]: """Required by DAGNode.""" return [self]
[docs] def leaves(self) -> list[BaseOperator]: """Required by DAGNode.""" return [self]
[docs] def output(self) -> XComArg: """Returns reference to XCom pushed by current operator.""" from airflow.models.xcom_arg import XComArg return XComArg(operator=self)
@property def is_setup(self) -> bool: """Whether the operator is a setup task. :meta private: """ return self._is_setup @is_setup.setter def is_setup(self, value: bool) -> None: """Setter for is_setup property. :meta private: """ if self.is_teardown and value: raise ValueError(f"Cannot mark task '{self.task_id}' as setup; task is already a teardown.") self._is_setup = value @property def is_teardown(self) -> bool: """Whether the operator is a teardown task. :meta private: """ return self._is_teardown @is_teardown.setter def is_teardown(self, value: bool) -> None: """ Setter for is_teardown property. :meta private: """ if self.is_setup and value: raise ValueError(f"Cannot mark task '{self.task_id}' as teardown; task is already a setup.") self._is_teardown = value @staticmethod
[docs] def xcom_push( context: Any, key: str, value: Any, execution_date: datetime | None = None, ) -> None: """ Make an XCom available for tasks to pull. :param context: Execution Context Dictionary :param key: A key for the XCom :param value: A value for the XCom. The value is pickled and stored in the database. :param execution_date: if provided, the XCom will not be visible until this date. This can be used, for example, to send a message to a task on a future date without it being immediately visible. """ context["ti"].xcom_push(key=key, value=value, execution_date=execution_date)
@staticmethod @provide_session
[docs] def xcom_pull( context: Any, task_ids: str | list[str] | None = None, dag_id: str | None = None, key: str = XCOM_RETURN_KEY, include_prior_dates: bool | None = None, session: Session = NEW_SESSION, ) -> Any: """ Pull XComs that optionally meet certain criteria. The default value for `key` limits the search to XComs that were returned by other tasks (as opposed to those that were pushed manually). To remove this filter, pass key=None (or any desired value). If a single task_id string is provided, the result is the value of the most recent matching XCom from that task_id. If multiple task_ids are provided, a tuple of matching values is returned. None is returned whenever no matches are found. :param context: Execution Context Dictionary :param key: A key for the XCom. If provided, only XComs with matching keys will be returned. The default key is 'return_value', also available as a constant XCOM_RETURN_KEY. This key is automatically given to XComs returned by tasks (as opposed to being pushed manually). To remove the filter, pass key=None. :param task_ids: Only XComs from tasks with matching ids will be pulled. Can pass None to remove the filter. :param dag_id: If provided, only pulls XComs from this DAG. If None (default), the DAG of the calling task is used. :param include_prior_dates: If False, only XComs from the current execution_date are returned. If True, XComs from previous dates are returned as well. """ return context["ti"].xcom_pull( key=key, task_ids=task_ids, dag_id=dag_id, include_prior_dates=include_prior_dates, session=session, )
[docs] def get_serialized_fields(cls): """Stringified DAGs and operators contain exactly these fields.""" if not cls.__serialized_fields: from airflow.models.dag import DagContext # make sure the following dummy task is not added to current active # dag in context, otherwise, it will result in # `RuntimeError: dictionary changed size during iteration` # Exception in SerializedDAG.serialize_dag() call. DagContext.push_context_managed_dag(None) cls.__serialized_fields = frozenset( vars(BaseOperator(task_id="test")).keys() - { "upstream_task_ids", "default_args", "dag", "_dag", "label", "_BaseOperator__instantiated", "_BaseOperator__init_kwargs", "_BaseOperator__from_mapped", "_is_setup", "_is_teardown", "_on_failure_fail_dagrun", } | { # Class level defaults need to be added to this list "start_date", "end_date", "_task_type", "_operator_name", "subdag", "ui_color", "ui_fgcolor", "template_ext", "template_fields", "template_fields_renderers", "params", "is_setup", "is_teardown", "on_failure_fail_dagrun", } ) DagContext.pop_context_managed_dag() return cls.__serialized_fields
[docs] def serialize_for_task_group(self) -> tuple[DagAttributeTypes, Any]: """Required by DAGNode.""" return DagAttributeTypes.OP, self.task_id
[docs] def inherits_from_empty_operator(self): """Used to determine if an Operator is inherited from EmptyOperator.""" # This looks like `isinstance(self, EmptyOperator) would work, but this also # needs to cope when `self` is a Serialized instance of a EmptyOperator or one # of its subclasses (which don't inherit from anything but BaseOperator). return getattr(self, "_is_empty", False)
[docs] def defer( self, *, trigger: BaseTrigger, method_name: str, kwargs: dict[str, Any] | None = None, timeout: timedelta | None = None, ): """ Mark this Operator "deferred", suspending its execution until the provided trigger fires an event. This is achieved by raising a special exception (TaskDeferred) which is caught in the main _execute_task wrapper. """ raise TaskDeferred(trigger=trigger, method_name=method_name, kwargs=kwargs, timeout=timeout)
def unmap(self, resolve: None | dict[str, Any] | tuple[Context, Session]) -> BaseOperator: """Get the "normal" operator from the current operator. Since a BaseOperator is not mapped to begin with, this simply returns the original operator. :meta private: """ return self
# TODO: Deprecate for Airflow 3.0
[docs]Chainable = Union[DependencyMixin, Sequence[DependencyMixin]]
[docs]def chain(*tasks: DependencyMixin | Sequence[DependencyMixin]) -> None: r""" Given a number of tasks, builds a dependency chain. This function accepts values of BaseOperator (aka tasks), EdgeModifiers (aka Labels), XComArg, TaskGroups, or lists containing any mix of these types (or a mix in the same list). If you want to chain between two lists you must ensure they have the same length. Using classic operators/sensors: .. code-block:: python chain(t1, [t2, t3], [t4, t5], t6) is equivalent to:: / -> t2 -> t4 \ t1 -> t6 \ -> t3 -> t5 / .. code-block:: python t1.set_downstream(t2) t1.set_downstream(t3) t2.set_downstream(t4) t3.set_downstream(t5) t4.set_downstream(t6) t5.set_downstream(t6) Using task-decorated functions aka XComArgs: .. code-block:: python chain(x1(), [x2(), x3()], [x4(), x5()], x6()) is equivalent to:: / -> x2 -> x4 \ x1 -> x6 \ -> x3 -> x5 / .. code-block:: python x1 = x1() x2 = x2() x3 = x3() x4 = x4() x5 = x5() x6 = x6() x1.set_downstream(x2) x1.set_downstream(x3) x2.set_downstream(x4) x3.set_downstream(x5) x4.set_downstream(x6) x5.set_downstream(x6) Using TaskGroups: .. code-block:: python chain(t1, task_group1, task_group2, t2) t1.set_downstream(task_group1) task_group1.set_downstream(task_group2) task_group2.set_downstream(t2) It is also possible to mix between classic operator/sensor, EdgeModifiers, XComArg, and TaskGroups: .. code-block:: python chain(t1, [Label("branch one"), Label("branch two")], [x1(), x2()], task_group1, x3()) is equivalent to:: / "branch one" -> x1 \ t1 -> task_group1 -> x3 \ "branch two" -> x2 / .. code-block:: python x1 = x1() x2 = x2() x3 = x3() label1 = Label("branch one") label2 = Label("branch two") t1.set_downstream(label1) label1.set_downstream(x1) t2.set_downstream(label2) label2.set_downstream(x2) x1.set_downstream(task_group1) x2.set_downstream(task_group1) task_group1.set_downstream(x3) # or x1 = x1() x2 = x2() x3 = x3() t1.set_downstream(x1, edge_modifier=Label("branch one")) t1.set_downstream(x2, edge_modifier=Label("branch two")) x1.set_downstream(task_group1) x2.set_downstream(task_group1) task_group1.set_downstream(x3) :param tasks: Individual and/or list of tasks, EdgeModifiers, XComArgs, or TaskGroups to set dependencies """ for index, up_task in enumerate(tasks[:-1]): down_task = tasks[index + 1] if isinstance(up_task, DependencyMixin): up_task.set_downstream(down_task) continue if isinstance(down_task, DependencyMixin): down_task.set_upstream(up_task) continue if not isinstance(up_task, Sequence) or not isinstance(down_task, Sequence): raise TypeError(f"Chain not supported between instances of {type(up_task)} and {type(down_task)}") up_task_list = up_task down_task_list = down_task if len(up_task_list) != len(down_task_list): raise AirflowException( f"Chain not supported for different length Iterable. " f"Got {len(up_task_list)} and {len(down_task_list)}." ) for up_t, down_t in zip(up_task_list, down_task_list): up_t.set_downstream(down_t)
[docs]def cross_downstream( from_tasks: Sequence[DependencyMixin], to_tasks: DependencyMixin | Sequence[DependencyMixin], ): r""" Set downstream dependencies for all tasks in from_tasks to all tasks in to_tasks. Using classic operators/sensors: .. code-block:: python cross_downstream(from_tasks=[t1, t2, t3], to_tasks=[t4, t5, t6]) is equivalent to:: t1 ---> t4 \ / t2 -X -> t5 / \ t3 ---> t6 .. code-block:: python t1.set_downstream(t4) t1.set_downstream(t5) t1.set_downstream(t6) t2.set_downstream(t4) t2.set_downstream(t5) t2.set_downstream(t6) t3.set_downstream(t4) t3.set_downstream(t5) t3.set_downstream(t6) Using task-decorated functions aka XComArgs: .. code-block:: python cross_downstream(from_tasks=[x1(), x2(), x3()], to_tasks=[x4(), x5(), x6()]) is equivalent to:: x1 ---> x4 \ / x2 -X -> x5 / \ x3 ---> x6 .. code-block:: python x1 = x1() x2 = x2() x3 = x3() x4 = x4() x5 = x5() x6 = x6() x1.set_downstream(x4) x1.set_downstream(x5) x1.set_downstream(x6) x2.set_downstream(x4) x2.set_downstream(x5) x2.set_downstream(x6) x3.set_downstream(x4) x3.set_downstream(x5) x3.set_downstream(x6) It is also possible to mix between classic operator/sensor and XComArg tasks: .. code-block:: python cross_downstream(from_tasks=[t1, x2(), t3], to_tasks=[x1(), t2, x3()]) is equivalent to:: t1 ---> x1 \ / x2 -X -> t2 / \ t3 ---> x3 .. code-block:: python x1 = x1() x2 = x2() x3 = x3() t1.set_downstream(x1) t1.set_downstream(t2) t1.set_downstream(x3) x2.set_downstream(x1) x2.set_downstream(t2) x2.set_downstream(x3) t3.set_downstream(x1) t3.set_downstream(t2) t3.set_downstream(x3) :param from_tasks: List of tasks or XComArgs to start from. :param to_tasks: List of tasks or XComArgs to set as downstream dependencies. """ for task in from_tasks: task.set_downstream(to_tasks)
[docs]def chain_linear(*elements: DependencyMixin | Sequence[DependencyMixin]): """ Helper to simplify task dependency definition. E.g.: suppose you want precedence like so:: ╭─op2─╮ ╭─op4─╮ op1─┤ ├─├─op5─┤─op7 ╰-op3─╯ ╰-op6─╯ Then you can accomplish like so:: chain_linear( op1, [op2, op3], [op4, op5, op6], op7 ) :param elements: a list of operators / lists of operators """ if not elements: raise ValueError("No tasks provided; nothing to do.") prev_elem = None deps_set = False for curr_elem in elements: if isinstance(curr_elem, EdgeModifier): raise ValueError("Labels are not supported by chain_linear") if prev_elem is not None: for task in prev_elem: task >> curr_elem if not deps_set: deps_set = True prev_elem = [curr_elem] if isinstance(curr_elem, DependencyMixin) else curr_elem if not deps_set: raise ValueError("No dependencies were set. Did you forget to expand with `*`?")
# pyupgrade assumes all type annotations can be lazily evaluated, but this is # not the case for attrs-decorated classes, since cattrs needs to evaluate the # annotation expressions at runtime, and Python before 3.9.0 does not lazily # evaluate those. Putting the expression in a top-level assignment statement # communicates this runtime requirement to pyupgrade.
[docs]BaseOperatorClassList = List[Type[BaseOperator]]

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