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from typing import Optional, cast
import six
from sqlalchemy import (
Column, Integer, String, Boolean, PickleType, Index, UniqueConstraint, func, DateTime, or_,
and_
)
from sqlalchemy.exc import IntegrityError
from sqlalchemy.ext.declarative import declared_attr
from sqlalchemy.orm import synonym
from sqlalchemy.orm.session import Session
from airflow.exceptions import AirflowException
from airflow.models.base import ID_LEN, Base
from airflow.settings import Stats, task_instance_mutation_hook
from airflow.ti_deps.dep_context import DepContext
from airflow.utils import timezone
from airflow.utils.db import provide_session
from airflow.utils.log.logging_mixin import LoggingMixin
from airflow.utils.sqlalchemy import UtcDateTime
from airflow.utils.state import State
[docs]class DagRun(Base, LoggingMixin):
"""
DagRun describes an instance of a Dag. It can be created
by the scheduler (for regular runs) or by an external trigger
"""
[docs] __tablename__ = "dag_run"
[docs] ID_PREFIX = 'scheduled__'
[docs] id = Column(Integer, primary_key=True)
[docs] dag_id = Column(String(ID_LEN))
[docs] execution_date = Column(UtcDateTime, default=timezone.utcnow)
[docs] start_date = Column(UtcDateTime, default=timezone.utcnow)
[docs] end_date = Column(UtcDateTime)
[docs] _state = Column('state', String(50), default=State.RUNNING)
[docs] run_id = Column(String(ID_LEN))
[docs] external_trigger = Column(Boolean, default=True)
[docs] conf = Column(PickleType)
[docs] __table_args__ = (
Index('dag_id_state', dag_id, _state),
UniqueConstraint('dag_id', 'execution_date'),
UniqueConstraint('dag_id', 'run_id'),
)
[docs] def __repr__(self):
return (
'<DagRun {dag_id} @ {execution_date}: {run_id}, '
'externally triggered: {external_trigger}>'
).format(
dag_id=self.dag_id,
execution_date=self.execution_date,
run_id=self.run_id,
external_trigger=self.external_trigger)
[docs] def get_state(self):
return self._state
[docs] def set_state(self, state):
if self._state != state:
self._state = state
self.end_date = timezone.utcnow() if self._state in State.finished() else None
@declared_attr
[docs] def state(self):
return synonym('_state',
descriptor=property(self.get_state, self.set_state))
@classmethod
[docs] def id_for_date(cls, date, prefix=ID_FORMAT_PREFIX):
return prefix.format(date.isoformat()[:19])
@provide_session
[docs] def refresh_from_db(self, session=None):
"""
Reloads the current dagrun from the database
:param session: database session
"""
DR = DagRun
exec_date = func.cast(self.execution_date, DateTime)
dr = session.query(DR).filter(
DR.dag_id == self.dag_id,
func.cast(DR.execution_date, DateTime) == exec_date,
DR.run_id == self.run_id
).one()
self.id = dr.id
self.state = dr.state
@staticmethod
@provide_session
[docs] def find(dag_id=None, run_id=None, execution_date=None,
state=None, external_trigger=None, no_backfills=False,
session=None):
"""
Returns a set of dag runs for the given search criteria.
:param dag_id: the dag_id to find dag runs for
:type dag_id: int, list
:param run_id: defines the the run id for this dag run
:type run_id: str
:param execution_date: the execution date
:type execution_date: datetime.datetime
:param state: the state of the dag run
:type state: str
:param external_trigger: whether this dag run is externally triggered
:type external_trigger: bool
:param no_backfills: return no backfills (True), return all (False).
Defaults to False
:type no_backfills: bool
:param session: database session
:type session: sqlalchemy.orm.session.Session
"""
DR = DagRun
qry = session.query(DR)
if dag_id:
qry = qry.filter(DR.dag_id == dag_id)
if run_id:
qry = qry.filter(DR.run_id == run_id)
if execution_date:
if isinstance(execution_date, list):
qry = qry.filter(DR.execution_date.in_(execution_date))
else:
qry = qry.filter(DR.execution_date == execution_date)
if state:
qry = qry.filter(DR.state == state)
if external_trigger is not None:
qry = qry.filter(DR.external_trigger == external_trigger)
if no_backfills:
# in order to prevent a circular dependency
from airflow.jobs import BackfillJob
qry = qry.filter(DR.run_id.notlike(BackfillJob.ID_PREFIX + '%'))
dr = qry.order_by(DR.execution_date).all()
return dr
@provide_session
[docs] def get_task_instances(self, state=None, session=None):
"""
Returns the task instances for this dag run
"""
from airflow.models.taskinstance import TaskInstance # Avoid circular import
tis = session.query(TaskInstance).filter(
TaskInstance.dag_id == self.dag_id,
TaskInstance.execution_date == self.execution_date,
)
if state:
if isinstance(state, six.string_types):
tis = tis.filter(TaskInstance.state == state)
else:
# this is required to deal with NULL values
if None in state:
tis = tis.filter(
or_(TaskInstance.state.in_(state),
TaskInstance.state.is_(None))
)
else:
tis = tis.filter(TaskInstance.state.in_(state))
if self.dag and self.dag.partial:
tis = tis.filter(TaskInstance.task_id.in_(self.dag.task_ids))
return tis.all()
@provide_session
[docs] def get_task_instance(self, task_id, session=None):
"""
Returns the task instance specified by task_id for this dag run
:param task_id: the task id
"""
from airflow.models.taskinstance import TaskInstance # Avoid circular import
TI = TaskInstance
ti = session.query(TI).filter(
TI.dag_id == self.dag_id,
TI.execution_date == self.execution_date,
TI.task_id == task_id
).first()
return ti
[docs] def get_dag(self):
"""
Returns the Dag associated with this DagRun.
:return: DAG
"""
if not self.dag:
raise AirflowException("The DAG (.dag) for {} needs to be set"
.format(self))
return self.dag
@provide_session
[docs] def get_previous_dagrun(self, state=None, session=None):
# type: (Optional[str], Optional[Session]) -> Optional['DagRun']
"""The previous DagRun, if there is one"""
session = cast(Session, session) # mypy
filters = [
DagRun.dag_id == self.dag_id,
DagRun.execution_date < self.execution_date,
]
if state is not None:
filters.append(DagRun.state == state)
return session.query(DagRun).filter(
*filters
).order_by(
DagRun.execution_date.desc()
).first()
@provide_session
[docs] def get_previous_scheduled_dagrun(self, session=None):
"""The previous, SCHEDULED DagRun, if there is one"""
dag = self.get_dag()
return session.query(DagRun).filter(
DagRun.dag_id == self.dag_id,
DagRun.execution_date == dag.previous_schedule(self.execution_date)
).first()
@provide_session
[docs] def update_state(self, session=None):
"""
Determines the overall state of the DagRun based on the state
of its TaskInstances.
:return: State
"""
dag = self.get_dag()
tis = self.get_task_instances(session=session)
self.log.debug("Updating state for %s considering %s task(s)", self, len(tis))
for ti in list(tis):
# skip in db?
if ti.state == State.REMOVED:
tis.remove(ti)
else:
ti.task = dag.get_task(ti.task_id)
# pre-calculate
# db is faster
start_dttm = timezone.utcnow()
unfinished_tasks = self.get_task_instances(
state=State.unfinished(),
session=session
)
none_depends_on_past = all(not t.task.depends_on_past for t in unfinished_tasks)
none_task_concurrency = all(t.task.task_concurrency is None
for t in unfinished_tasks)
# small speed up
if unfinished_tasks and none_depends_on_past and none_task_concurrency:
# todo: this can actually get pretty slow: one task costs between 0.01-015s
no_dependencies_met = True
for ut in unfinished_tasks:
# We need to flag upstream and check for changes because upstream
# failures/re-schedules can result in deadlock false positives
old_state = ut.state
deps_met = ut.are_dependencies_met(
dep_context=DepContext(
flag_upstream_failed=True,
ignore_in_retry_period=True,
ignore_in_reschedule_period=True),
session=session)
if deps_met or old_state != ut.current_state(session=session):
no_dependencies_met = False
break
duration = (timezone.utcnow() - start_dttm).total_seconds() * 1000
Stats.timing("dagrun.dependency-check.{}".format(self.dag_id), duration)
leaf_task_ids = {t.task_id for t in dag.leaves}
leaf_tis = [ti for ti in tis if ti.task_id in leaf_task_ids]
# if all roots finished and at least one failed, the run failed
if not unfinished_tasks and any(
leaf_ti.state in {State.FAILED, State.UPSTREAM_FAILED} for leaf_ti in leaf_tis
):
self.log.info('Marking run %s failed', self)
self.set_state(State.FAILED)
dag.handle_callback(self, success=False, reason='task_failure',
session=session)
# if all leafs succeeded and no unfinished tasks, the run succeeded
elif not unfinished_tasks and all(
leaf_ti.state in {State.SUCCESS, State.SKIPPED} for leaf_ti in leaf_tis
):
self.log.info('Marking run %s successful', self)
self.set_state(State.SUCCESS)
dag.handle_callback(self, success=True, reason='success', session=session)
# if *all tasks* are deadlocked, the run failed
elif (unfinished_tasks and none_depends_on_past and
none_task_concurrency and no_dependencies_met):
self.log.info('Deadlock; marking run %s failed', self)
self.set_state(State.FAILED)
dag.handle_callback(self, success=False, reason='all_tasks_deadlocked',
session=session)
# finally, if the roots aren't done, the dag is still running
else:
self.set_state(State.RUNNING)
self._emit_duration_stats_for_finished_state()
# todo: determine we want to use with_for_update to make sure to lock the run
session.merge(self)
session.commit()
return self.state
[docs] def _emit_duration_stats_for_finished_state(self):
if self.state == State.RUNNING:
return
duration = (self.end_date - self.start_date)
if self.state is State.SUCCESS:
Stats.timing('dagrun.duration.success.{}'.format(self.dag_id), duration)
elif self.state == State.FAILED:
Stats.timing('dagrun.duration.failed.{}'.format(self.dag_id), duration)
@provide_session
[docs] def verify_integrity(self, session=None):
"""
Verifies the DagRun by checking for removed tasks or tasks that are not in the
database yet. It will set state to removed or add the task if required.
"""
from airflow.models.taskinstance import TaskInstance # Avoid circular import
dag = self.get_dag()
tis = self.get_task_instances(session=session)
# check for removed or restored tasks
task_ids = set()
for ti in tis:
task_instance_mutation_hook(ti)
task_ids.add(ti.task_id)
task = None
try:
task = dag.get_task(ti.task_id)
except AirflowException:
if ti.state == State.REMOVED:
pass # ti has already been removed, just ignore it
elif self.state is not State.RUNNING and not dag.partial:
self.log.warning("Failed to get task '{}' for dag '{}'. "
"Marking it as removed.".format(ti, dag))
Stats.incr(
"task_removed_from_dag.{}".format(dag.dag_id), 1, 1)
ti.state = State.REMOVED
is_task_in_dag = task is not None
should_restore_task = is_task_in_dag and ti.state == State.REMOVED
if should_restore_task:
self.log.info("Restoring task '{}' which was previously "
"removed from DAG '{}'".format(ti, dag))
Stats.incr("task_restored_to_dag.{}".format(dag.dag_id), 1, 1)
ti.state = State.NONE
session.merge(ti)
# check for missing tasks
for task in six.itervalues(dag.task_dict):
if task.start_date > self.execution_date and not self.is_backfill:
continue
if task.task_id not in task_ids:
Stats.incr(
"task_instance_created-{}".format(task.__class__.__name__),
1, 1)
ti = TaskInstance(task, self.execution_date)
task_instance_mutation_hook(ti)
session.add(ti)
try:
session.commit()
except IntegrityError as err:
self.log.info(str(err))
self.log.info(
'Hit IntegrityError while creating the TIs for %s - %s',
dag.dag_id, self.execution_date
)
self.log.info('Doing session rollback.')
session.rollback()
@staticmethod
[docs] def get_run(session, dag_id, execution_date):
"""
:param dag_id: DAG ID
:type dag_id: unicode
:param execution_date: execution date
:type execution_date: datetime
:return: DagRun corresponding to the given dag_id and execution date
if one exists. None otherwise.
:rtype: airflow.models.DagRun
"""
qry = session.query(DagRun).filter(
DagRun.dag_id == dag_id,
DagRun.external_trigger == False, # noqa
DagRun.execution_date == execution_date,
)
return qry.first()
@property
[docs] def is_backfill(self):
from airflow.jobs import BackfillJob
return (
self.run_id is not None and
self.run_id.startswith(BackfillJob.ID_PREFIX)
)
@classmethod
@provide_session
[docs] def get_latest_runs(cls, session):
"""Returns the latest DagRun for each DAG. """
subquery = (
session
.query(
cls.dag_id,
func.max(cls.execution_date).label('execution_date'))
.group_by(cls.dag_id)
.subquery()
)
dagruns = (
session
.query(cls)
.join(subquery,
and_(cls.dag_id == subquery.c.dag_id,
cls.execution_date == subquery.c.execution_date))
.all()
)
return dagruns