airflow mappedoperator 源码
airflow mappedoperator 代码
文件路径：/airflow/models/mappedoperator.py
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
from __future__ import annotations
import collections
import collections.abc
import contextlib
import copy
import datetime
import warnings
from typing import TYPE_CHECKING, Any, ClassVar, Collection, Iterable, Iterator, Mapping, Sequence, Union
import attr
import pendulum
from sqlalchemy import func, or_
from sqlalchemy.orm.session import Session
from airflow import settings
from airflow.compat.functools import cache, cached_property
from airflow.exceptions import AirflowException, UnmappableOperator
from airflow.models.abstractoperator import (
DEFAULT_IGNORE_FIRST_DEPENDS_ON_PAST,
DEFAULT_OWNER,
DEFAULT_POOL_SLOTS,
DEFAULT_PRIORITY_WEIGHT,
DEFAULT_QUEUE,
DEFAULT_RETRIES,
DEFAULT_RETRY_DELAY,
DEFAULT_TRIGGER_RULE,
DEFAULT_WEIGHT_RULE,
AbstractOperator,
TaskStateChangeCallback,
)
from airflow.models.expandinput import (
DictOfListsExpandInput,
ExpandInput,
ListOfDictsExpandInput,
NotFullyPopulated,
OperatorExpandArgument,
OperatorExpandKwargsArgument,
get_mappable_types,
)
from airflow.models.param import ParamsDict
from airflow.models.pool import Pool
from airflow.serialization.enums import DagAttributeTypes
from airflow.ti_deps.deps.base_ti_dep import BaseTIDep
from airflow.ti_deps.deps.mapped_task_expanded import MappedTaskIsExpanded
from airflow.typing_compat import Literal
from airflow.utils.context import Context, context_update_for_unmapped
from airflow.utils.helpers import is_container, prevent_duplicates
from airflow.utils.operator_resources import Resources
from airflow.utils.state import State, TaskInstanceState
from airflow.utils.trigger_rule import TriggerRule
from airflow.utils.types import NOTSET
if TYPE_CHECKING:
import jinja2 # Slow import.
from airflow.models.baseoperator import BaseOperator, BaseOperatorLink
from airflow.models.dag import DAG
from airflow.models.operator import Operator
from airflow.models.taskinstance import TaskInstance
from airflow.models.xcom_arg import XComArg
from airflow.utils.task_group import TaskGroup
ValidationSource = Union[Literal["expand"], Literal["partial"]]
def validate_mapping_kwargs(op: type[BaseOperator], func: ValidationSource, value: dict[str, Any]) -> None:
# use a dict so order of args is same as code order
unknown_args = value.copy()
for klass in op.mro():
init = klass.__init__ # type: ignore[misc]
try:
param_names = init._BaseOperatorMeta__param_names
except AttributeError:
continue
for name in param_names:
value = unknown_args.pop(name, NOTSET)
if func != "expand":
continue
if value is NOTSET:
continue
if isinstance(value, get_mappable_types()):
continue
type_name = type(value).__name__
error = f"{op.__name__}.expand() got an unexpected type {type_name!r} for keyword argument {name}"
raise ValueError(error)
if not unknown_args:
return # If we have no args left to check: stop looking at the MRO chain.
if len(unknown_args) == 1:
error = f"an unexpected keyword argument {unknown_args.popitem()[0]!r}"
else:
names = ", ".join(repr(n) for n in unknown_args)
error = f"unexpected keyword arguments {names}"
raise TypeError(f"{op.__name__}.{func}() got {error}")
def ensure_xcomarg_return_value(arg: Any) -> None:
from airflow.models.xcom_arg import XCOM_RETURN_KEY, XComArg
if isinstance(arg, XComArg):
for operator, key in arg.iter_references():
if key != XCOM_RETURN_KEY:
raise ValueError(f"cannot map over XCom with custom key {key!r} from {operator}")
elif not is_container(arg):
return
elif isinstance(arg, collections.abc.Mapping):
for v in arg.values():
ensure_xcomarg_return_value(v)
elif isinstance(arg, collections.abc.Iterable):
for v in arg:
ensure_xcomarg_return_value(v)
@attr.define(kw_only=True, repr=False)
class OperatorPartial:
"""An "intermediate state" returned by ``BaseOperator.partial()``.
This only exists at DAG-parsing time; the only intended usage is for the
user to call ``.expand()`` on it at some point (usually in a method chain) to
create a ``MappedOperator`` to add into the DAG.
"""
operator_class: type[BaseOperator]
kwargs: dict[str, Any]
params: ParamsDict | dict
_expand_called: bool = False # Set when expand() is called to ease user debugging.
def __attrs_post_init__(self):
from airflow.operators.subdag import SubDagOperator
if issubclass(self.operator_class, SubDagOperator):
raise TypeError("Mapping over deprecated SubDagOperator is not supported")
validate_mapping_kwargs(self.operator_class, "partial", self.kwargs)
def __repr__(self) -> str:
args = ", ".join(f"{k}={v!r}" for k, v in self.kwargs.items())
return f"{self.operator_class.__name__}.partial({args})"
def __del__(self):
if not self._expand_called:
try:
task_id = repr(self.kwargs["task_id"])
except KeyError:
task_id = f"at {hex(id(self))}"
warnings.warn(f"Task {task_id} was never mapped!")
def expand(self, **mapped_kwargs: OperatorExpandArgument) -> MappedOperator:
if not mapped_kwargs:
raise TypeError("no arguments to expand against")
validate_mapping_kwargs(self.operator_class, "expand", mapped_kwargs)
prevent_duplicates(self.kwargs, mapped_kwargs, fail_reason="unmappable or already specified")
# Since the input is already checked at parse time, we can set strict
# to False to skip the checks on execution.
return self._expand(DictOfListsExpandInput(mapped_kwargs), strict=False)
def expand_kwargs(self, kwargs: OperatorExpandKwargsArgument, *, strict: bool = True) -> MappedOperator:
from airflow.models.xcom_arg import XComArg
if isinstance(kwargs, collections.abc.Sequence):
for item in kwargs:
if not isinstance(item, (XComArg, collections.abc.Mapping)):
raise TypeError(f"expected XComArg or list[dict], not {type(kwargs).__name__}")
elif not isinstance(kwargs, XComArg):
raise TypeError(f"expected XComArg or list[dict], not {type(kwargs).__name__}")
return self._expand(ListOfDictsExpandInput(kwargs), strict=strict)
def _expand(self, expand_input: ExpandInput, *, strict: bool) -> MappedOperator:
from airflow.operators.empty import EmptyOperator
self._expand_called = True
ensure_xcomarg_return_value(expand_input.value)
partial_kwargs = self.kwargs.copy()
task_id = partial_kwargs.pop("task_id")
dag = partial_kwargs.pop("dag")
task_group = partial_kwargs.pop("task_group")
start_date = partial_kwargs.pop("start_date")
end_date = partial_kwargs.pop("end_date")
try:
operator_name = self.operator_class.custom_operator_name # type: ignore
except AttributeError:
operator_name = self.operator_class.__name__
op = MappedOperator(
operator_class=self.operator_class,
expand_input=expand_input,
partial_kwargs=partial_kwargs,
task_id=task_id,
params=self.params,
deps=MappedOperator.deps_for(self.operator_class),
operator_extra_links=self.operator_class.operator_extra_links,
template_ext=self.operator_class.template_ext,
template_fields=self.operator_class.template_fields,
template_fields_renderers=self.operator_class.template_fields_renderers,
ui_color=self.operator_class.ui_color,
ui_fgcolor=self.operator_class.ui_fgcolor,
is_empty=issubclass(self.operator_class, EmptyOperator),
task_module=self.operator_class.__module__,
task_type=self.operator_class.__name__,
operator_name=operator_name,
dag=dag,
task_group=task_group,
start_date=start_date,
end_date=end_date,
disallow_kwargs_override=strict,
# For classic operators, this points to expand_input because kwargs
# to BaseOperator.expand() contribute to operator arguments.
expand_input_attr="expand_input",
)
return op
@attr.define(
kw_only=True,
# Disable custom __getstate__ and __setstate__ generation since it interacts
# badly with Airflow's DAG serialization and pickling. When a mapped task is
# deserialized, subclasses are coerced into MappedOperator, but when it goes
# through DAG pickling, all attributes defined in the subclasses are dropped
# by attrs's custom state management. Since attrs does not do anything too
# special here (the logic is only important for slots=True), we use Python's
# built-in implementation, which works (as proven by good old BaseOperator).
getstate_setstate=False,
)
class MappedOperator(AbstractOperator):
"""Object representing a mapped operator in a DAG."""
# This attribute serves double purpose. For a "normal" operator instance
# loaded from DAG, this holds the underlying non-mapped operator class that
# can be used to create an unmapped operator for execution. For an operator
# recreated from a serialized DAG, however, this holds the serialized data
# that can be used to unmap this into a SerializedBaseOperator.
operator_class: type[BaseOperator] | dict[str, Any]
expand_input: ExpandInput
partial_kwargs: dict[str, Any]
# Needed for serialization.
task_id: str
params: ParamsDict | dict
deps: frozenset[BaseTIDep]
operator_extra_links: Collection[BaseOperatorLink]
template_ext: Sequence[str]
template_fields: Collection[str]
template_fields_renderers: dict[str, str]
ui_color: str
ui_fgcolor: str
_is_empty: bool
_task_module: str
_task_type: str
_operator_name: str
dag: DAG | None
task_group: TaskGroup | None
start_date: pendulum.DateTime | None
end_date: pendulum.DateTime | None
upstream_task_ids: set[str] = attr.ib(factory=set, init=False)
downstream_task_ids: set[str] = attr.ib(factory=set, init=False)
_disallow_kwargs_override: bool
"""Whether execution fails if ``expand_input`` has duplicates to ``partial_kwargs``.
If *False*, values from ``expand_input`` under duplicate keys override those
under corresponding keys in ``partial_kwargs``.
"""
_expand_input_attr: str
"""Where to get kwargs to calculate expansion length against.
This should be a name to call ``getattr()`` on.
"""
is_mapped: ClassVar[bool] = True
subdag: None = None # Since we don't support SubDagOperator, this is always None.
HIDE_ATTRS_FROM_UI: ClassVar[frozenset[str]] = AbstractOperator.HIDE_ATTRS_FROM_UI | frozenset(
(
'parse_time_mapped_ti_count',
'operator_class',
)
)
def __hash__(self):
return id(self)
def __repr__(self):
return f"<Mapped({self._task_type}): {self.task_id}>"
def __attrs_post_init__(self):
from airflow.models.xcom_arg import XComArg
if self.task_group:
self.task_group.add(self)
if self.dag:
self.dag.add_task(self)
XComArg.apply_upstream_relationship(self, self.expand_input.value)
for k, v in self.partial_kwargs.items():
if k in self.template_fields:
XComArg.apply_upstream_relationship(self, v)
if self.partial_kwargs.get('sla') is not None:
raise AirflowException(
f"SLAs are unsupported with mapped tasks. Please set `sla=None` for task "
f"{self.task_id!r}."
)
@classmethod
@cache
def get_serialized_fields(cls):
# Not using 'cls' here since we only want to serialize base fields.
return frozenset(attr.fields_dict(MappedOperator)) - {
"dag",
"deps",
"is_mapped",
"expand_input", # This is needed to be able to accept XComArg.
"subdag",
"task_group",
"upstream_task_ids",
}
@staticmethod
@cache
def deps_for(operator_class: type[BaseOperator]) -> frozenset[BaseTIDep]:
operator_deps = operator_class.deps
if not isinstance(operator_deps, collections.abc.Set):
raise UnmappableOperator(
f"'deps' must be a set defined as a class-level variable on {operator_class.__name__}, "
f"not a {type(operator_deps).__name__}"
)
return operator_deps | {MappedTaskIsExpanded()}
@property
def task_type(self) -> str:
"""Implementing Operator."""
return self._task_type
@property
def operator_name(self) -> str:
return self._operator_name
@property
def inherits_from_empty_operator(self) -> bool:
"""Implementing Operator."""
return self._is_empty
@property
def roots(self) -> Sequence[AbstractOperator]:
"""Implementing DAGNode."""
return [self]
@property
def leaves(self) -> Sequence[AbstractOperator]:
"""Implementing DAGNode."""
return [self]
@property
def owner(self) -> str: # type: ignore[override]
return self.partial_kwargs.get("owner", DEFAULT_OWNER)
@property
def email(self) -> None | str | Iterable[str]:
return self.partial_kwargs.get("email")
@property
def trigger_rule(self) -> TriggerRule:
return self.partial_kwargs.get("trigger_rule", DEFAULT_TRIGGER_RULE)
@property
def depends_on_past(self) -> bool:
return bool(self.partial_kwargs.get("depends_on_past"))
@property
def ignore_first_depends_on_past(self) -> bool:
value = self.partial_kwargs.get("ignore_first_depends_on_past", DEFAULT_IGNORE_FIRST_DEPENDS_ON_PAST)
return bool(value)
@property
def wait_for_downstream(self) -> bool:
return bool(self.partial_kwargs.get("wait_for_downstream"))
@property
def retries(self) -> int | None:
return self.partial_kwargs.get("retries", DEFAULT_RETRIES)
@property
def queue(self) -> str:
return self.partial_kwargs.get("queue", DEFAULT_QUEUE)
@property
def pool(self) -> str:
return self.partial_kwargs.get("pool", Pool.DEFAULT_POOL_NAME)
@property
def pool_slots(self) -> str | None:
return self.partial_kwargs.get("pool_slots", DEFAULT_POOL_SLOTS)
@property
def execution_timeout(self) -> datetime.timedelta | None:
return self.partial_kwargs.get("execution_timeout")
@property
def max_retry_delay(self) -> datetime.timedelta | None:
return self.partial_kwargs.get("max_retry_delay")
@property
def retry_delay(self) -> datetime.timedelta:
return self.partial_kwargs.get("retry_delay", DEFAULT_RETRY_DELAY)
@property
def retry_exponential_backoff(self) -> bool:
return bool(self.partial_kwargs.get("retry_exponential_backoff"))
@property
def priority_weight(self) -> int: # type: ignore[override]
return self.partial_kwargs.get("priority_weight", DEFAULT_PRIORITY_WEIGHT)
@property
def weight_rule(self) -> int: # type: ignore[override]
return self.partial_kwargs.get("weight_rule", DEFAULT_WEIGHT_RULE)
@property
def sla(self) -> datetime.timedelta | None:
return self.partial_kwargs.get("sla")
@property
def max_active_tis_per_dag(self) -> int | None:
return self.partial_kwargs.get("max_active_tis_per_dag")
@property
def resources(self) -> Resources | None:
return self.partial_kwargs.get("resources")
@property
def on_execute_callback(self) -> TaskStateChangeCallback | None:
return self.partial_kwargs.get("on_execute_callback")
@property
def on_failure_callback(self) -> TaskStateChangeCallback | None:
return self.partial_kwargs.get("on_failure_callback")
@property
def on_retry_callback(self) -> TaskStateChangeCallback | None:
return self.partial_kwargs.get("on_retry_callback")
@property
def on_success_callback(self) -> TaskStateChangeCallback | None:
return self.partial_kwargs.get("on_success_callback")
@property
def run_as_user(self) -> str | None:
return self.partial_kwargs.get("run_as_user")
@property
def executor_config(self) -> dict:
return self.partial_kwargs.get("executor_config", {})
@property # type: ignore[override]
def inlets(self) -> list[Any]: # type: ignore[override]
return self.partial_kwargs.get("inlets", [])
@inlets.setter
def inlets(self, value: list[Any]) -> None: # type: ignore[override]
self.partial_kwargs["inlets"] = value
@property # type: ignore[override]
def outlets(self) -> list[Any]: # type: ignore[override]
return self.partial_kwargs.get("outlets", [])
@outlets.setter
def outlets(self, value: list[Any]) -> None: # type: ignore[override]
self.partial_kwargs["outlets"] = value
@property
def doc(self) -> str | None:
return self.partial_kwargs.get("doc")
@property
def doc_md(self) -> str | None:
return self.partial_kwargs.get("doc_md")
@property
def doc_json(self) -> str | None:
return self.partial_kwargs.get("doc_json")
@property
def doc_yaml(self) -> str | None:
return self.partial_kwargs.get("doc_yaml")
@property
def doc_rst(self) -> str | None:
return self.partial_kwargs.get("doc_rst")
def get_dag(self) -> DAG | None:
"""Implementing Operator."""
return self.dag
@property
def output(self) -> XComArg:
"""Returns reference to XCom pushed by current operator"""
from airflow.models.xcom_arg import XComArg
return XComArg(operator=self)
def serialize_for_task_group(self) -> tuple[DagAttributeTypes, Any]:
"""Implementing DAGNode."""
return DagAttributeTypes.OP, self.task_id
def _expand_mapped_kwargs(self, context: Context, session: Session) -> tuple[Mapping[str, Any], set[int]]:
"""Get the kwargs to create the unmapped operator.
This exists because taskflow operators expand against op_kwargs, not the
entire operator kwargs dict.
"""
return self._get_specified_expand_input().resolve(context, session)
def _get_unmap_kwargs(self, mapped_kwargs: Mapping[str, Any], *, strict: bool) -> dict[str, Any]:
"""Get init kwargs to unmap the underlying operator class.
:param mapped_kwargs: The dict returned by ``_expand_mapped_kwargs``.
"""
if strict:
prevent_duplicates(
self.partial_kwargs,
mapped_kwargs,
fail_reason="unmappable or already specified",
)
# If params appears in the mapped kwargs, we need to merge it into the
# partial params, overriding existing keys.
params = copy.copy(self.params)
with contextlib.suppress(KeyError):
params.update(mapped_kwargs["params"])
# Ordering is significant; mapped kwargs should override partial ones,
# and the specially handled params should be respected.
return {
"task_id": self.task_id,
"dag": self.dag,
"task_group": self.task_group,
"start_date": self.start_date,
"end_date": self.end_date,
**self.partial_kwargs,
**mapped_kwargs,
"params": params,
}
def unmap(self, resolve: None | Mapping[str, Any] | tuple[Context, Session]) -> BaseOperator:
"""Get the "normal" Operator after applying the current mapping.
The *resolve* argument is only used if ``operator_class`` is a real
class, i.e. if this operator is not serialized. If ``operator_class`` is
not a class (i.e. this DAG has been deserialized), this returns a
SerializedBaseOperator that "looks like" the actual unmapping result.
If *resolve* is a two-tuple (context, session), the information is used
to resolve the mapped arguments into init arguments. If it is a mapping,
no resolving happens, the mapping directly provides those init arguments
resolved from mapped kwargs.
:meta private:
"""
if isinstance(self.operator_class, type):
if isinstance(resolve, collections.abc.Mapping):
kwargs = resolve
elif resolve is not None:
kwargs, _ = self._expand_mapped_kwargs(*resolve)
else:
raise RuntimeError("cannot unmap a non-serialized operator without context")
kwargs = self._get_unmap_kwargs(kwargs, strict=self._disallow_kwargs_override)
op = self.operator_class(**kwargs, _airflow_from_mapped=True)
# We need to overwrite task_id here because BaseOperator further
# mangles the task_id based on the task hierarchy (namely, group_id
# is prepended, and '__N' appended to deduplicate). This is hacky,
# but better than duplicating the whole mangling logic.
op.task_id = self.task_id
return op
# After a mapped operator is serialized, there's no real way to actually
# unmap it since we've lost access to the underlying operator class.
# This tries its best to simply "forward" all the attributes on this
# mapped operator to a new SerializedBaseOperator instance.
from airflow.serialization.serialized_objects import SerializedBaseOperator
op = SerializedBaseOperator(task_id=self.task_id, params=self.params, _airflow_from_mapped=True)
SerializedBaseOperator.populate_operator(op, self.operator_class)
return op
def _get_specified_expand_input(self) -> ExpandInput:
"""Input received from the expand call on the operator."""
return getattr(self, self._expand_input_attr)
def expand_mapped_task(self, run_id: str, *, session: Session) -> tuple[Sequence[TaskInstance], int]:
"""Create the mapped task instances for mapped task.
:return: The newly created mapped TaskInstances (if any) in ascending order by map index, and the
maximum map_index.
"""
from airflow.models.taskinstance import TaskInstance
from airflow.settings import task_instance_mutation_hook
total_length: int | None
try:
total_length = self._get_specified_expand_input().get_total_map_length(run_id, session=session)
except NotFullyPopulated as e:
self.log.info(
"Cannot expand %r for run %s; missing upstream values: %s",
self,
run_id,
sorted(e.missing),
)
total_length = None
state: TaskInstanceState | None = None
unmapped_ti: TaskInstance | None = (
session.query(TaskInstance)
.filter(
TaskInstance.dag_id == self.dag_id,
TaskInstance.task_id == self.task_id,
TaskInstance.run_id == run_id,
TaskInstance.map_index == -1,
or_(TaskInstance.state.in_(State.unfinished), TaskInstance.state.is_(None)),
)
.one_or_none()
)
all_expanded_tis: list[TaskInstance] = []
if unmapped_ti:
# The unmapped task instance still exists and is unfinished, i.e. we
# haven't tried to run it before.
if total_length is None:
# If the map length cannot be calculated (due to unavailable
# upstream sources), fail the unmapped task.
unmapped_ti.state = TaskInstanceState.UPSTREAM_FAILED
indexes_to_map: Iterable[int] = ()
elif total_length < 1:
# If the upstream maps this to a zero-length value, simply mark
# the unmapped task instance as SKIPPED (if needed).
self.log.info(
"Marking %s as SKIPPED since the map has %d values to expand",
unmapped_ti,
total_length,
)
unmapped_ti.state = TaskInstanceState.SKIPPED
indexes_to_map = ()
else:
# Otherwise convert this into the first mapped index, and create
# TaskInstance for other indexes.
unmapped_ti.map_index = 0
self.log.debug("Updated in place to become %s", unmapped_ti)
all_expanded_tis.append(unmapped_ti)
indexes_to_map = range(1, total_length)
state = unmapped_ti.state
elif not total_length:
# Nothing to fixup.
indexes_to_map = ()
else:
# Only create "missing" ones.
current_max_mapping = (
session.query(func.max(TaskInstance.map_index))
.filter(
TaskInstance.dag_id == self.dag_id,
TaskInstance.task_id == self.task_id,
TaskInstance.run_id == run_id,
)
.scalar()
)
indexes_to_map = range(current_max_mapping + 1, total_length)
for index in indexes_to_map:
# TODO: Make more efficient with bulk_insert_mappings/bulk_save_mappings.
ti = TaskInstance(self, run_id=run_id, map_index=index, state=state)
self.log.debug("Expanding TIs upserted %s", ti)
task_instance_mutation_hook(ti)
ti = session.merge(ti)
ti.refresh_from_task(self) # session.merge() loses task information.
all_expanded_tis.append(ti)
# Coerce the None case to 0 -- these two are almost treated identically,
# except the unmapped ti (if exists) is marked to different states.
total_expanded_ti_count = total_length or 0
# Set to "REMOVED" any (old) TaskInstances with map indices greater
# than the current map value
session.query(TaskInstance).filter(
TaskInstance.dag_id == self.dag_id,
TaskInstance.task_id == self.task_id,
TaskInstance.run_id == run_id,
TaskInstance.map_index >= total_expanded_ti_count,
).update({TaskInstance.state: TaskInstanceState.REMOVED})
session.flush()
return all_expanded_tis, total_expanded_ti_count - 1
def prepare_for_execution(self) -> MappedOperator:
# Since a mapped operator cannot be used for execution, and an unmapped
# BaseOperator needs to be created later (see render_template_fields),
# we don't need to create a copy of the MappedOperator here.
return self
def iter_mapped_dependencies(self) -> Iterator[Operator]:
"""Upstream dependencies that provide XComs used by this task for task mapping."""
from airflow.models.xcom_arg import XComArg
for ref in XComArg.iter_xcom_args(self._get_specified_expand_input()):
for operator, _ in ref.iter_references():
yield operator
@cached_property
def parse_time_mapped_ti_count(self) -> int | None:
"""Number of mapped TaskInstances that can be created at DagRun create time.
This only considers literal mapped arguments, and would return *None*
when any non-literal values are used for mapping.
:return: None if non-literal mapped arg encountered, or the total
number of mapped TIs this task should have.
"""
return self._get_specified_expand_input().get_parse_time_mapped_ti_count()
@cache
def get_mapped_ti_count(self, run_id: str, *, session: Session) -> int | None:
"""Number of mapped TaskInstances that can be created at run time.
This considers both literal and non-literal mapped arguments, and the
result is therefore available when all depended tasks have finished. The
return value should be identical to ``parse_time_mapped_ti_count`` if
all mapped arguments are literal.
:return: None if upstream tasks are not complete yet, or the total
number of mapped TIs this task should have.
"""
try:
return self._get_specified_expand_input().get_total_map_length(run_id, session=session)
except NotFullyPopulated:
return None
def render_template_fields(
self,
context: Context,
jinja_env: jinja2.Environment | None = None,
) -> None:
"""Template all attributes listed in *self.template_fields*.
This updates *context* to reference the map-expanded task and relevant
information, without modifying the mapped operator. The expanded task
in *context* is then rendered in-place.
:param context: Context dict with values to apply on content.
:param jinja_env: Jinja environment to use for rendering.
"""
if not jinja_env:
jinja_env = self.get_template_env()
# Ideally we'd like to pass in session as an argument to this function,
# but we can't easily change this function signature since operators
# could override this. We can't use @provide_session since it closes and
# expunges everything, which we don't want to do when we are so "deep"
# in the weeds here. We don't close this session for the same reason.
session = settings.Session()
mapped_kwargs, seen_oids = self._expand_mapped_kwargs(context, session)
unmapped_task = self.unmap(mapped_kwargs)
context_update_for_unmapped(context, unmapped_task)
self._do_render_template_fields(
parent=unmapped_task,
template_fields=self.template_fields,
context=context,
jinja_env=jinja_env,
seen_oids=seen_oids,
session=session,
)
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