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new 6549b1798f6 Remove zombie ti from its executor (#42932)
6549b1798f6 is described below
commit 6549b1798f6e682b5db6060d9aa89dd2e155ffb5
Author: Tzu-ping Chung <[email protected]>
AuthorDate: Wed Oct 16 10:32:57 2024 +0800
Remove zombie ti from its executor (#42932)
---
airflow/jobs/scheduler_job_runner.py | 119 +++++++++++++++-------------
airflow/models/taskinstance.py | 7 +-
docs/apache-airflow/core-concepts/tasks.rst | 4 +-
tests/jobs/test_scheduler_job.py | 68 ++++++++--------
tests_common/test_utils/mock_executor.py | 5 +-
5 files changed, 105 insertions(+), 98 deletions(-)
diff --git a/airflow/jobs/scheduler_job_runner.py
b/airflow/jobs/scheduler_job_runner.py
index 30f58885a9a..951602e14e6 100644
--- a/airflow/jobs/scheduler_job_runner.py
+++ b/airflow/jobs/scheduler_job_runner.py
@@ -1077,7 +1077,7 @@ class SchedulerJobRunner(BaseJobRunner, LoggingMixin):
timers.call_regular_interval(
conf.getfloat("scheduler", "zombie_detection_interval",
fallback=10.0),
- self._find_zombies,
+ self._find_and_purge_zombies,
)
timers.call_regular_interval(60.0,
self._update_dag_run_state_for_paused_dags)
@@ -1953,73 +1953,80 @@ class SchedulerJobRunner(BaseJobRunner, LoggingMixin):
if num_timed_out_tasks:
self.log.info("Timed out %i deferred tasks without fired
triggers", num_timed_out_tasks)
- # [START find_zombies]
- def _find_zombies(self) -> None:
+ # [START find_and_purge_zombies]
+ def _find_and_purge_zombies(self) -> None:
"""
- Find zombie task instances and create a TaskCallbackRequest to be
handled by the DAG processor.
+ Find and purge zombie task instances.
- Zombie instances are tasks haven't heartbeated for too long or have a
no-longer-running LocalTaskJob.
+ Zombie instances are tasks that failed to heartbeat for too long, or
+ have a no-longer-running LocalTaskJob.
+
+ A TaskCallbackRequest is also created for the killed zombie to be
+ handled by the DAG processor, and the executor is informed to no longer
+ count the zombie as running when it calculates parallelism.
"""
+ with create_session() as session:
+ if zombies := self._find_zombies(session=session):
+ self._purge_zombies(zombies, session=session)
+
+ def _find_zombies(self, *, session: Session) -> list[tuple[TI, str, str]]:
from airflow.jobs.job import Job
self.log.debug("Finding 'running' jobs without a recent heartbeat")
limit_dttm = timezone.utcnow() -
timedelta(seconds=self._zombie_threshold_secs)
-
- with create_session() as session:
- zombies: list[tuple[TI, str, str]] = (
- session.execute(
- select(TI, DM.fileloc, DM.processor_subdir)
- .with_hint(TI, "USE INDEX (ti_state)",
dialect_name="mysql")
- .join(Job, TI.job_id == Job.id)
- .join(DM, TI.dag_id == DM.dag_id)
- .where(TI.state == TaskInstanceState.RUNNING)
- .where(
- or_(
- Job.state != JobState.RUNNING,
- Job.latest_heartbeat < limit_dttm,
- )
- )
- .where(Job.job_type == "LocalTaskJob")
- .where(TI.queued_by_job_id == self.job.id)
- )
- .unique()
- .all()
+ zombies = (
+ session.execute(
+ select(TI, DM.fileloc, DM.processor_subdir)
+ .with_hint(TI, "USE INDEX (ti_state)", dialect_name="mysql")
+ .join(Job, TI.job_id == Job.id)
+ .join(DM, TI.dag_id == DM.dag_id)
+ .where(TI.state == TaskInstanceState.RUNNING)
+ .where(or_(Job.state != JobState.RUNNING, Job.latest_heartbeat
< limit_dttm))
+ .where(Job.job_type == "LocalTaskJob")
+ .where(TI.queued_by_job_id == self.job.id)
)
-
+ .unique()
+ .all()
+ )
if zombies:
self.log.warning("Failing (%s) jobs without heartbeat after %s",
len(zombies), limit_dttm)
-
- with create_session() as session:
- for ti, file_loc, processor_subdir in zombies:
- zombie_message_details =
self._generate_zombie_message_details(ti)
- request = TaskCallbackRequest(
- full_filepath=file_loc,
- processor_subdir=processor_subdir,
- simple_task_instance=SimpleTaskInstance.from_ti(ti),
- msg=str(zombie_message_details),
- )
- session.add(
- Log(
- event="heartbeat timeout",
- task_instance=ti.key,
- extra=(
- f"Task did not emit heartbeat within time limit
({self._zombie_threshold_secs} "
- "seconds) and will be terminated. "
- "See
https://airflow.apache.org/docs/apache-airflow/";
-
"stable/core-concepts/tasks.html#zombie-undead-tasks"
- ),
- )
- )
- self.log.error(
- "Detected zombie job: %s "
- "(See https://airflow.apache.org/docs/apache-airflow/";
- "stable/core-concepts/tasks.html#zombie-undead-tasks)",
- request,
+ return zombies
+
+ def _purge_zombies(self, zombies: list[tuple[TI, str, str]], *, session:
Session) -> None:
+ for ti, file_loc, processor_subdir in zombies:
+ zombie_message_details = self._generate_zombie_message_details(ti)
+ request = TaskCallbackRequest(
+ full_filepath=file_loc,
+ processor_subdir=processor_subdir,
+ simple_task_instance=SimpleTaskInstance.from_ti(ti),
+ msg=str(zombie_message_details),
+ )
+ session.add(
+ Log(
+ event="heartbeat timeout",
+ task_instance=ti.key,
+ extra=(
+ f"Task did not emit heartbeat within time limit
({self._zombie_threshold_secs} "
+ "seconds) and will be terminated. "
+ "See https://airflow.apache.org/docs/apache-airflow/";
+ "stable/core-concepts/tasks.html#zombie-undead-tasks"
+ ),
)
- self.job.executor.send_callback(request)
- Stats.incr("zombies_killed", tags={"dag_id": ti.dag_id,
"task_id": ti.task_id})
+ )
+ self.log.error(
+ "Detected zombie job: %s "
+ "(See https://airflow.apache.org/docs/apache-airflow/";
+ "stable/core-concepts/tasks.html#zombie-undead-tasks)",
+ request,
+ )
+ self.job.executor.send_callback(request)
+ if (executor := self._try_to_load_executor(ti.executor)) is None:
+ self.log.warning("Cannot clean up zombie %r with non-existent
executor %s", ti, ti.executor)
+ continue
+ executor.change_state(ti.key, TaskInstanceState.FAILED,
remove_running=True)
+ Stats.incr("zombies_killed", tags={"dag_id": ti.dag_id, "task_id":
ti.task_id})
- # [END find_zombies]
+ # [END find_and_purge_zombies]
@staticmethod
def _generate_zombie_message_details(ti: TI) -> dict[str, Any]:
diff --git a/airflow/models/taskinstance.py b/airflow/models/taskinstance.py
index c1373e5d6a1..1dbe299f25b 100644
--- a/airflow/models/taskinstance.py
+++ b/airflow/models/taskinstance.py
@@ -154,7 +154,6 @@ if TYPE_CHECKING:
from sqlalchemy.sql.expression import ColumnOperators
from airflow.models.abstractoperator import TaskStateChangeCallback
- from airflow.models.asset import AssetEvent
from airflow.models.baseoperator import BaseOperator
from airflow.models.dag import DAG, DagModel
from airflow.models.dagrun import DagRun
@@ -3925,7 +3924,11 @@ class SimpleTaskInstance:
self.queue = queue
self.key = key
- def __eq__(self, other):
+ def __repr__(self) -> str:
+ attrs = ", ".join(f"{k}={v!r}" for k, v in self.__dict__.items())
+ return f"SimpleTaskInstance({attrs})"
+
+ def __eq__(self, other) -> bool:
if isinstance(other, self.__class__):
return self.__dict__ == other.__dict__
return NotImplemented
diff --git a/docs/apache-airflow/core-concepts/tasks.rst
b/docs/apache-airflow/core-concepts/tasks.rst
index 5adfe8be460..3f5a1a21b77 100644
--- a/docs/apache-airflow/core-concepts/tasks.rst
+++ b/docs/apache-airflow/core-concepts/tasks.rst
@@ -189,8 +189,8 @@ Below is the code snippet from the Airflow scheduler that
runs periodically to d
.. exampleinclude:: /../../airflow/jobs/scheduler_job_runner.py
:language: python
- :start-after: [START find_zombies]
- :end-before: [END find_zombies]
+ :start-after: [START find_and_purge_zombies]
+ :end-before: [END find_and_purge_zombies]
The explanation of the criteria used in the above snippet to detect zombie
tasks is as below:
diff --git a/tests/jobs/test_scheduler_job.py b/tests/jobs/test_scheduler_job.py
index f35ed29e7b1..01d1c5fe7a3 100644
--- a/tests/jobs/test_scheduler_job.py
+++ b/tests/jobs/test_scheduler_job.py
@@ -2976,8 +2976,8 @@ class TestSchedulerJob:
ti2s = tiq.filter(TaskInstance.task_id == "dummy2").all()
assert len(ti1s) == 0
assert len(ti2s) >= 2
- for task in ti2s:
- assert task.state == State.SUCCESS
+ for ti in ti2s:
+ assert ti.state == State.SUCCESS
@pytest.mark.parametrize(
"configs",
@@ -5539,36 +5539,37 @@ class TestSchedulerJob:
with pytest.raises(OperationalError):
check_if_trigger_timeout(1)
- def test_find_zombies_nothing(self):
+ def test_find_and_purge_zombies_nothing(self):
executor = MockExecutor(do_update=False)
scheduler_job = Job(executor=executor)
- self.job_runner = SchedulerJobRunner(scheduler_job)
- self.job_runner.processor_agent = mock.MagicMock()
-
- self.job_runner._find_zombies()
-
- scheduler_job.executor.callback_sink.send.assert_not_called()
+ with
mock.patch("airflow.executors.executor_loader.ExecutorLoader.load_executor") as
loader_mock:
+ loader_mock.return_value = executor
+ self.job_runner = SchedulerJobRunner(scheduler_job)
+ self.job_runner.processor_agent = mock.MagicMock()
+ self.job_runner._find_and_purge_zombies()
+ executor.callback_sink.send.assert_not_called()
- def test_find_zombies(self, load_examples):
+ def test_find_and_purge_zombies(self, load_examples, session):
dagbag = DagBag(TEST_DAG_FOLDER, read_dags_from_db=False)
- with create_session() as session:
- session.query(Job).delete()
- dag = dagbag.get_dag("example_branch_operator")
- dag.sync_to_db()
- data_interval =
dag.infer_automated_data_interval(DEFAULT_LOGICAL_DATE)
- triggered_by_kwargs = {"triggered_by": DagRunTriggeredByType.TEST}
if AIRFLOW_V_3_0_PLUS else {}
- dag_run = dag.create_dagrun(
- state=DagRunState.RUNNING,
- execution_date=DEFAULT_DATE,
- run_type=DagRunType.SCHEDULED,
- session=session,
- data_interval=data_interval,
- **triggered_by_kwargs,
- )
- scheduler_job = Job()
+ dag = dagbag.get_dag("example_branch_operator")
+ dag.sync_to_db()
+ data_interval = dag.infer_automated_data_interval(DEFAULT_LOGICAL_DATE)
+ triggered_by_kwargs = {"triggered_by": DagRunTriggeredByType.TEST} if
AIRFLOW_V_3_0_PLUS else {}
+ dag_run = dag.create_dagrun(
+ state=DagRunState.RUNNING,
+ execution_date=DEFAULT_DATE,
+ run_type=DagRunType.SCHEDULED,
+ session=session,
+ data_interval=data_interval,
+ **triggered_by_kwargs,
+ )
+
+ executor = MockExecutor()
+ scheduler_job = Job(executor=executor)
+ with
mock.patch("airflow.executors.executor_loader.ExecutorLoader.load_executor") as
loader_mock:
+ loader_mock.return_value = executor
self.job_runner = SchedulerJobRunner(job=scheduler_job,
subdir=os.devnull)
- scheduler_job.executor = MockExecutor()
self.job_runner.processor_agent = mock.MagicMock()
# We will provision 2 tasks so we can check we only find zombies
from this scheduler
@@ -5594,11 +5595,12 @@ class TestSchedulerJob:
ti.queued_by_job_id = scheduler_job.id
session.flush()
+ executor.running.add(ti.key) # The executor normally does this
during heartbeat.
+ self.job_runner._find_and_purge_zombies()
+ assert ti.key not in executor.running
- self.job_runner._find_zombies()
-
- scheduler_job.executor.callback_sink.send.assert_called_once()
- callback_requests =
scheduler_job.executor.callback_sink.send.call_args.args
+ executor.callback_sink.send.assert_called_once()
+ callback_requests = executor.callback_sink.send.call_args.args
assert len(callback_requests) == 1
callback_request = callback_requests[0]
assert isinstance(callback_request.simple_task_instance,
SimpleTaskInstance)
@@ -5610,10 +5612,6 @@ class TestSchedulerJob:
assert callback_request.simple_task_instance.run_id == ti.run_id
assert callback_request.simple_task_instance.map_index == ti.map_index
- with create_session() as session:
- session.query(TaskInstance).delete()
- session.query(Job).delete()
-
def test_zombie_message(self, load_examples):
"""
Check that the zombie message comes out as expected
@@ -5729,7 +5727,7 @@ class TestSchedulerJob:
scheduler_job.executor = MockExecutor()
self.job_runner.processor_agent = mock.MagicMock()
- self.job_runner._find_zombies()
+ self.job_runner._find_and_purge_zombies()
scheduler_job.executor.callback_sink.send.assert_called_once()
diff --git a/tests_common/test_utils/mock_executor.py
b/tests_common/test_utils/mock_executor.py
index 506c0447589..6d4791e8891 100644
--- a/tests_common/test_utils/mock_executor.py
+++ b/tests_common/test_utils/mock_executor.py
@@ -36,7 +36,6 @@ class MockExecutor(BaseExecutor):
def __init__(self, do_update=True, *args, **kwargs):
self.do_update = do_update
- self._running = []
self.callback_sink = MagicMock()
# A list of "batches" of tasks
@@ -88,8 +87,8 @@ class MockExecutor(BaseExecutor):
def end(self):
self.sync()
- def change_state(self, key, state, info=None):
- super().change_state(key, state, info=info)
+ def change_state(self, key, state, info=None, remove_running=False):
+ super().change_state(key, state, info=info,
remove_running=remove_running)
# The normal event buffer is cleared after reading, we want to keep
# a list of all events for testing
self.sorted_tasks.append((key, (state, info)))
