# -*- coding: utf-8 -*-
#
# Licensed 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 airflow.exceptions import AirflowException
from airflow.models import BaseOperator, Pool
from airflow.utils.decorators import apply_defaults
from airflow.utils.db import provide_session
from airflow.executors import DEFAULT_EXECUTOR
[docs]class SubDagOperator(BaseOperator):
template_fields = tuple()
ui_color = '#555'
ui_fgcolor = '#fff'
@provide_session
@apply_defaults
def __init__(
self,
subdag,
executor=DEFAULT_EXECUTOR,
*args, **kwargs):
"""
Yo dawg. This runs a sub dag. By convention, a sub dag's dag_id
should be prefixed by its parent and a dot. As in `parent.child`.
:param subdag: the DAG object to run as a subdag of the current DAG.
:type subdag: airflow.DAG
:param dag: the parent DAG
:type subdag: airflow.DAG
"""
if 'dag' not in kwargs:
raise AirflowException("Please pass in the `dag` param")
dag = kwargs['dag']
session = kwargs.pop('session')
super(SubDagOperator, self).__init__(*args, **kwargs)
# validate subdag name
if dag.dag_id + '.' + kwargs['task_id'] != subdag.dag_id:
raise AirflowException(
"The subdag's dag_id should have the form "
"'{{parent_dag_id}}.{{this_task_id}}'. Expected "
"'{d}.{t}'; received '{rcvd}'.".format(
d=dag.dag_id, t=kwargs['task_id'], rcvd=subdag.dag_id))
# validate that subdag operator and subdag tasks don't have a
# pool conflict
if self.pool:
pool = (
session
.query(Pool)
.filter(Pool.slots == 1)
.filter(Pool.pool == self.pool)
.first()
)
conflicts = [t for t in subdag.tasks if t.pool == self.pool]
if pool and any(t.pool == self.pool for t in subdag.tasks):
raise AirflowException(
'SubDagOperator {sd} and subdag task{plural} {t} both use '
'pool {p}, but the pool only has 1 slot. The subdag tasks'
'will never run.'.format(
sd=self.task_id,
plural=len(conflicts) > 1,
t=', '.join(t.task_id for t in conflicts),
p=self.pool
)
)
self.subdag = subdag
self.executor = executor
def execute(self, context):
ed = context['execution_date']
self.subdag.run(
start_date=ed, end_date=ed, donot_pickle=True,
executor=self.executor)