Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/airflow/models/skipmixin.py: 25%
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« prev ^ index » next coverage.py v7.0.1, created at 2022-12-25 06:11 +0000
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 warnings
21from typing import TYPE_CHECKING, Iterable, Sequence
23from airflow.exceptions import AirflowException, RemovedInAirflow3Warning
24from airflow.models.taskinstance import TaskInstance
25from airflow.utils import timezone
26from airflow.utils.log.logging_mixin import LoggingMixin
27from airflow.utils.session import NEW_SESSION, create_session, provide_session
28from airflow.utils.state import State
30if TYPE_CHECKING:
31 from pendulum import DateTime
32 from sqlalchemy import Session
34 from airflow.models.dagrun import DagRun
35 from airflow.models.operator import Operator
36 from airflow.models.taskmixin import DAGNode
38# The key used by SkipMixin to store XCom data.
39XCOM_SKIPMIXIN_KEY = "skipmixin_key"
41# The dictionary key used to denote task IDs that are skipped
42XCOM_SKIPMIXIN_SKIPPED = "skipped"
44# The dictionary key used to denote task IDs that are followed
45XCOM_SKIPMIXIN_FOLLOWED = "followed"
48def _ensure_tasks(nodes: Iterable[DAGNode]) -> Sequence[Operator]:
49 from airflow.models.baseoperator import BaseOperator
50 from airflow.models.mappedoperator import MappedOperator
52 return [n for n in nodes if isinstance(n, (BaseOperator, MappedOperator))]
55class SkipMixin(LoggingMixin):
56 """A Mixin to skip Tasks Instances"""
58 def _set_state_to_skipped(
59 self,
60 dag_run: DagRun,
61 tasks: Iterable[Operator],
62 session: Session,
63 ) -> None:
64 """Used internally to set state of task instances to skipped from the same dag run."""
65 now = timezone.utcnow()
67 session.query(TaskInstance).filter(
68 TaskInstance.dag_id == dag_run.dag_id,
69 TaskInstance.run_id == dag_run.run_id,
70 TaskInstance.task_id.in_(d.task_id for d in tasks),
71 ).update(
72 {
73 TaskInstance.state: State.SKIPPED,
74 TaskInstance.start_date: now,
75 TaskInstance.end_date: now,
76 },
77 synchronize_session=False,
78 )
80 @provide_session
81 def skip(
82 self,
83 dag_run: DagRun,
84 execution_date: DateTime,
85 tasks: Iterable[DAGNode],
86 session: Session = NEW_SESSION,
87 ):
88 """
89 Sets tasks instances to skipped from the same dag run.
91 If this instance has a `task_id` attribute, store the list of skipped task IDs to XCom
92 so that NotPreviouslySkippedDep knows these tasks should be skipped when they
93 are cleared.
95 :param dag_run: the DagRun for which to set the tasks to skipped
96 :param execution_date: execution_date
97 :param tasks: tasks to skip (not task_ids)
98 :param session: db session to use
99 """
100 task_list = _ensure_tasks(tasks)
101 if not task_list:
102 return
104 if execution_date and not dag_run:
105 from airflow.models.dagrun import DagRun
107 warnings.warn(
108 "Passing an execution_date to `skip()` is deprecated in favour of passing a dag_run",
109 RemovedInAirflow3Warning,
110 stacklevel=2,
111 )
113 dag_run = (
114 session.query(DagRun)
115 .filter(
116 DagRun.dag_id == task_list[0].dag_id,
117 DagRun.execution_date == execution_date,
118 )
119 .one()
120 )
121 elif execution_date and dag_run and execution_date != dag_run.execution_date:
122 raise ValueError(
123 "execution_date has a different value to dag_run.execution_date -- please only pass dag_run"
124 )
126 if dag_run is None:
127 raise ValueError("dag_run is required")
129 self._set_state_to_skipped(dag_run, task_list, session)
130 session.commit()
132 # SkipMixin may not necessarily have a task_id attribute. Only store to XCom if one is available.
133 task_id: str | None = getattr(self, "task_id", None)
134 if task_id is not None:
135 from airflow.models.xcom import XCom
137 XCom.set(
138 key=XCOM_SKIPMIXIN_KEY,
139 value={XCOM_SKIPMIXIN_SKIPPED: [d.task_id for d in task_list]},
140 task_id=task_id,
141 dag_id=dag_run.dag_id,
142 run_id=dag_run.run_id,
143 session=session,
144 )
146 def skip_all_except(self, ti: TaskInstance, branch_task_ids: None | str | Iterable[str]):
147 """
148 This method implements the logic for a branching operator; given a single
149 task ID or list of task IDs to follow, this skips all other tasks
150 immediately downstream of this operator.
152 branch_task_ids is stored to XCom so that NotPreviouslySkippedDep knows skipped tasks or
153 newly added tasks should be skipped when they are cleared.
154 """
155 self.log.info("Following branch %s", branch_task_ids)
156 if isinstance(branch_task_ids, str):
157 branch_task_id_set = {branch_task_ids}
158 elif isinstance(branch_task_ids, Iterable):
159 branch_task_id_set = set(branch_task_ids)
160 invalid_task_ids_type = {
161 (bti, type(bti).__name__) for bti in branch_task_ids if not isinstance(bti, str)
162 }
163 if invalid_task_ids_type:
164 raise AirflowException(
165 f"'branch_task_ids' expected all task IDs are strings. "
166 f"Invalid tasks found: {invalid_task_ids_type}."
167 )
168 elif branch_task_ids is None:
169 branch_task_id_set = set()
170 else:
171 raise AirflowException(
172 "'branch_task_ids' must be either None, a task ID, or an Iterable of IDs, "
173 f"but got {type(branch_task_ids).__name__!r}."
174 )
176 dag_run = ti.get_dagrun()
177 task = ti.task
178 dag = task.dag
179 if TYPE_CHECKING:
180 assert dag
182 valid_task_ids = set(dag.task_ids)
183 invalid_task_ids = branch_task_id_set - valid_task_ids
184 if invalid_task_ids:
185 raise AirflowException(
186 "'branch_task_ids' must contain only valid task_ids. "
187 f"Invalid tasks found: {invalid_task_ids}."
188 )
190 downstream_tasks = _ensure_tasks(task.downstream_list)
192 if downstream_tasks:
193 # For a branching workflow that looks like this, when "branch" does skip_all_except("task1"),
194 # we intuitively expect both "task1" and "join" to execute even though strictly speaking,
195 # "join" is also immediately downstream of "branch" and should have been skipped. Therefore,
196 # we need a special case here for such empty branches: Check downstream tasks of branch_task_ids.
197 # In case the task to skip is also downstream of branch_task_ids, we add it to branch_task_ids and
198 # exclude it from skipping.
199 #
200 # branch -----> join
201 # \ ^
202 # v /
203 # task1
204 #
205 for branch_task_id in list(branch_task_id_set):
206 branch_task_id_set.update(dag.get_task(branch_task_id).get_flat_relative_ids(upstream=False))
208 skip_tasks = [t for t in downstream_tasks if t.task_id not in branch_task_id_set]
209 follow_task_ids = [t.task_id for t in downstream_tasks if t.task_id in branch_task_id_set]
211 self.log.info("Skipping tasks %s", [t.task_id for t in skip_tasks])
212 with create_session() as session:
213 self._set_state_to_skipped(dag_run, skip_tasks, session=session)
214 # For some reason, session.commit() needs to happen before xcom_push.
215 # Otherwise the session is not committed.
216 session.commit()
217 ti.xcom_push(key=XCOM_SKIPMIXIN_KEY, value={XCOM_SKIPMIXIN_FOLLOWED: follow_task_ids})