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1#
2# Licensed to the Apache Software Foundation (ASF) under one
3# or more contributor license agreements. See the NOTICE file
4# distributed with this work for additional information
5# regarding copyright ownership. The ASF licenses this file
6# to you under the Apache License, Version 2.0 (the
7# "License"); you may not use this file except in compliance
8# with the License. You may obtain a copy of the License at
9#
10# http://www.apache.org/licenses/LICENSE-2.0
11#
12# Unless required by applicable law or agreed to in writing,
13# software distributed under the License is distributed on an
14# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15# KIND, either express or implied. See the License for the
16# specific language governing permissions and limitations
17# under the License.
18from __future__ import annotations
20import collections.abc
21import functools
22import operator
23from collections.abc import Sized
24from typing import TYPE_CHECKING, Any, Dict, Iterable, Mapping, NamedTuple, Sequence, Union
26import attr
28from airflow.utils.mixins import ResolveMixin
29from airflow.utils.session import NEW_SESSION, provide_session
31if TYPE_CHECKING:
32 from sqlalchemy.orm import Session
34 from airflow.models.operator import Operator
35 from airflow.models.xcom_arg import XComArg
36 from airflow.typing_compat import TypeGuard
37 from airflow.utils.context import Context
39ExpandInput = Union["DictOfListsExpandInput", "ListOfDictsExpandInput"]
41# Each keyword argument to expand() can be an XComArg, sequence, or dict (not
42# any mapping since we need the value to be ordered).
43OperatorExpandArgument = Union["MappedArgument", "XComArg", Sequence, Dict[str, Any]]
45# The single argument of expand_kwargs() can be an XComArg, or a list with each
46# element being either an XComArg or a dict.
47OperatorExpandKwargsArgument = Union["XComArg", Sequence[Union["XComArg", Mapping[str, Any]]]]
50@attr.define(kw_only=True)
51class MappedArgument(ResolveMixin):
52 """Stand-in stub for task-group-mapping arguments.
54 This is very similar to an XComArg, but resolved differently. Declared here
55 (instead of in the task group module) to avoid import cycles.
56 """
58 _input: ExpandInput
59 _key: str
61 def get_task_map_length(self, run_id: str, *, session: Session) -> int | None:
62 # TODO (AIP-42): Implement run-time task map length inspection. This is
63 # needed when we implement task mapping inside a mapped task group.
64 raise NotImplementedError()
66 def iter_references(self) -> Iterable[tuple[Operator, str]]:
67 yield from self._input.iter_references()
69 @provide_session
70 def resolve(self, context: Context, *, session: Session = NEW_SESSION) -> Any:
71 data, _ = self._input.resolve(context, session=session)
72 return data[self._key]
75# To replace tedious isinstance() checks.
76def is_mappable(v: Any) -> TypeGuard[OperatorExpandArgument]:
77 from airflow.models.xcom_arg import XComArg
79 return isinstance(v, (MappedArgument, XComArg, Mapping, Sequence)) and not isinstance(v, str)
82# To replace tedious isinstance() checks.
83def _is_parse_time_mappable(v: OperatorExpandArgument) -> TypeGuard[Mapping | Sequence]:
84 from airflow.models.xcom_arg import XComArg
86 return not isinstance(v, (MappedArgument, XComArg))
89# To replace tedious isinstance() checks.
90def _needs_run_time_resolution(v: OperatorExpandArgument) -> TypeGuard[MappedArgument | XComArg]:
91 from airflow.models.xcom_arg import XComArg
93 return isinstance(v, (MappedArgument, XComArg))
96class NotFullyPopulated(RuntimeError):
97 """Raise when ``get_map_lengths`` cannot populate all mapping metadata.
99 This is generally due to not all upstream tasks have finished when the
100 function is called.
101 """
103 def __init__(self, missing: set[str]) -> None:
104 self.missing = missing
106 def __str__(self) -> str:
107 keys = ", ".join(repr(k) for k in sorted(self.missing))
108 return f"Failed to populate all mapping metadata; missing: {keys}"
111class DictOfListsExpandInput(NamedTuple):
112 """Storage type of a mapped operator's mapped kwargs.
114 This is created from ``expand(**kwargs)``.
115 """
117 value: dict[str, OperatorExpandArgument]
119 def _iter_parse_time_resolved_kwargs(self) -> Iterable[tuple[str, Sized]]:
120 """Generate kwargs with values available on parse-time."""
121 return ((k, v) for k, v in self.value.items() if _is_parse_time_mappable(v))
123 def get_parse_time_mapped_ti_count(self) -> int:
124 if not self.value:
125 return 0
126 literal_values = [len(v) for _, v in self._iter_parse_time_resolved_kwargs()]
127 if len(literal_values) != len(self.value):
128 literal_keys = (k for k, _ in self._iter_parse_time_resolved_kwargs())
129 raise NotFullyPopulated(set(self.value).difference(literal_keys))
130 return functools.reduce(operator.mul, literal_values, 1)
132 def _get_map_lengths(self, run_id: str, *, session: Session) -> dict[str, int]:
133 """Return dict of argument name to map length.
135 If any arguments are not known right now (upstream task not finished),
136 they will not be present in the dict.
137 """
139 # TODO: This initiates one database call for each XComArg. Would it be
140 # more efficient to do one single db call and unpack the value here?
141 def _get_length(v: OperatorExpandArgument) -> int | None:
142 if _needs_run_time_resolution(v):
143 return v.get_task_map_length(run_id, session=session)
144 # Unfortunately a user-defined TypeGuard cannot apply negative type
145 # narrowing. https://github.com/python/typing/discussions/1013
146 if TYPE_CHECKING:
147 assert isinstance(v, Sized)
148 return len(v)
150 map_lengths_iterator = ((k, _get_length(v)) for k, v in self.value.items())
152 map_lengths = {k: v for k, v in map_lengths_iterator if v is not None}
153 if len(map_lengths) < len(self.value):
154 raise NotFullyPopulated(set(self.value).difference(map_lengths))
155 return map_lengths
157 def get_total_map_length(self, run_id: str, *, session: Session) -> int:
158 if not self.value:
159 return 0
160 lengths = self._get_map_lengths(run_id, session=session)
161 return functools.reduce(operator.mul, (lengths[name] for name in self.value), 1)
163 def _expand_mapped_field(self, key: str, value: Any, context: Context, *, session: Session) -> Any:
164 if _needs_run_time_resolution(value):
165 value = value.resolve(context, session=session)
166 map_index = context["ti"].map_index
167 if map_index < 0:
168 raise RuntimeError("can't resolve task-mapping argument without expanding")
169 all_lengths = self._get_map_lengths(context["run_id"], session=session)
171 def _find_index_for_this_field(index: int) -> int:
172 # Need to use the original user input to retain argument order.
173 for mapped_key in reversed(self.value):
174 mapped_length = all_lengths[mapped_key]
175 if mapped_length < 1:
176 raise RuntimeError(f"cannot expand field mapped to length {mapped_length!r}")
177 if mapped_key == key:
178 return index % mapped_length
179 index //= mapped_length
180 return -1
182 found_index = _find_index_for_this_field(map_index)
183 if found_index < 0:
184 return value
185 if isinstance(value, collections.abc.Sequence):
186 return value[found_index]
187 if not isinstance(value, dict):
188 raise TypeError(f"can't map over value of type {type(value)}")
189 for i, (k, v) in enumerate(value.items()):
190 if i == found_index:
191 return k, v
192 raise IndexError(f"index {map_index} is over mapped length")
194 def iter_references(self) -> Iterable[tuple[Operator, str]]:
195 from airflow.models.xcom_arg import XComArg
197 for x in self.value.values():
198 if isinstance(x, XComArg):
199 yield from x.iter_references()
201 def resolve(self, context: Context, session: Session) -> tuple[Mapping[str, Any], set[int]]:
202 data = {k: self._expand_mapped_field(k, v, context, session=session) for k, v in self.value.items()}
203 literal_keys = {k for k, _ in self._iter_parse_time_resolved_kwargs()}
204 resolved_oids = {id(v) for k, v in data.items() if k not in literal_keys}
205 return data, resolved_oids
208def _describe_type(value: Any) -> str:
209 if value is None:
210 return "None"
211 return type(value).__name__
214class ListOfDictsExpandInput(NamedTuple):
215 """Storage type of a mapped operator's mapped kwargs.
217 This is created from ``expand_kwargs(xcom_arg)``.
218 """
220 value: OperatorExpandKwargsArgument
222 def get_parse_time_mapped_ti_count(self) -> int:
223 if isinstance(self.value, collections.abc.Sized):
224 return len(self.value)
225 raise NotFullyPopulated({"expand_kwargs() argument"})
227 def get_total_map_length(self, run_id: str, *, session: Session) -> int:
228 if isinstance(self.value, collections.abc.Sized):
229 return len(self.value)
230 length = self.value.get_task_map_length(run_id, session=session)
231 if length is None:
232 raise NotFullyPopulated({"expand_kwargs() argument"})
233 return length
235 def iter_references(self) -> Iterable[tuple[Operator, str]]:
236 from airflow.models.xcom_arg import XComArg
238 if isinstance(self.value, XComArg):
239 yield from self.value.iter_references()
240 else:
241 for x in self.value:
242 if isinstance(x, XComArg):
243 yield from x.iter_references()
245 def resolve(self, context: Context, session: Session) -> tuple[Mapping[str, Any], set[int]]:
246 map_index = context["ti"].map_index
247 if map_index < 0:
248 raise RuntimeError("can't resolve task-mapping argument without expanding")
250 mapping: Any
251 if isinstance(self.value, collections.abc.Sized):
252 mapping = self.value[map_index]
253 if not isinstance(mapping, collections.abc.Mapping):
254 mapping = mapping.resolve(context, session)
255 else:
256 mappings = self.value.resolve(context, session)
257 if not isinstance(mappings, collections.abc.Sequence):
258 raise ValueError(f"expand_kwargs() expects a list[dict], not {_describe_type(mappings)}")
259 mapping = mappings[map_index]
261 if not isinstance(mapping, collections.abc.Mapping):
262 raise ValueError(f"expand_kwargs() expects a list[dict], not list[{_describe_type(mapping)}]")
264 for key in mapping:
265 if not isinstance(key, str):
266 raise ValueError(
267 f"expand_kwargs() input dict keys must all be str, "
268 f"but {key!r} is of type {_describe_type(key)}"
269 )
270 # filter out parse time resolved values from the resolved_oids
271 resolved_oids = {id(v) for k, v in mapping.items() if not _is_parse_time_mappable(v)}
273 return mapping, resolved_oids
276EXPAND_INPUT_EMPTY = DictOfListsExpandInput({}) # Sentinel value.
278_EXPAND_INPUT_TYPES = {
279 "dict-of-lists": DictOfListsExpandInput,
280 "list-of-dicts": ListOfDictsExpandInput,
281}
284def get_map_type_key(expand_input: ExpandInput) -> str:
285 return next(k for k, v in _EXPAND_INPUT_TYPES.items() if v == type(expand_input))
288def create_expand_input(kind: str, value: Any) -> ExpandInput:
289 return _EXPAND_INPUT_TYPES[kind](value)