Qian Yu created AIRFLOW-6497: -------------------------------- Summary: Scheduler creates DagBag in the same process with outdated info Key: AIRFLOW-6497 URL: https://issues.apache.org/jira/browse/AIRFLOW-6497 Project: Apache Airflow Issue Type: Bug Components: scheduler Affects Versions: 1.10.7 Reporter: Qian Yu
The following code in scheduler_job.py seems to be called in the same process as the scheduler. It creates a DagBag. But since scheduler is a long running process, it does not pick up the latest changes made to DAGs. For example, changes to retries count, on_failure_callback, newly added tasks, etc are not reflected. {code:python} if ti.try_number == try_number and ti.state == State.QUEUED: msg = ("Executor reports task instance {} finished ({}) " "although the task says its {}. Was the task " "killed externally?".format(ti, state, ti.state)) Stats.incr('scheduler.tasks.killed_externally') self.log.error(msg) try: simple_dag = simple_dag_bag.get_dag(dag_id) dagbag = models.DagBag(simple_dag.full_filepath) dag = dagbag.get_dag(dag_id) ti.task = dag.get_task(task_id) ti.handle_failure(msg) except Exception: self.log.error("Cannot load the dag bag to handle failure for %s" ". Setting task to FAILED without callbacks or " "retries. Do you have enough resources?", ti) ti.state = State.FAILED session.merge(ti) session.commit() {code} This causes errors such as AttributeError due to stale code being hit. E.g. when someone added a .join attribute to CustomOperator without bouncing the scheduler, this is what he would get after a CeleryWorker timeout error causes this line to be hit: {code} [2020-01-05 22:25:45,951] {dagbag.py:207} ERROR - Failed to import: /dags/dag1.py Traceback (most recent call last): File "/lib/python3.6/site-packages/airflow/models/dagbag.py", line 204, in process_file m = imp.load_source(mod_name, filepath) File "/usr/lib/python3.6/imp.py", line 172, in load_source module = _load(spec) File "<frozen importlib._bootstrap>", line 684, in _load File "<frozen importlib._bootstrap>", line 665, in _load_unlocked File "<frozen importlib._bootstrap_external>", line 678, in exec_module File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed File "/dags/dag1.py", line 280, in <module> task1 >> task2.join AttributeError: 'CustomOperator' object has no attribute 'join' [2020-01-05 22:25:45,951] {scheduler_job.py:1314} ERROR - Cannot load the dag bag to handle failure for <TaskInstance: dag1.task1 2020-01-02 00:00:00+00:00 [queued]>. Setting task to FAILED without callbacks or retries. Do you have enough resou {code} -- This message was sent by Atlassian Jira (v8.3.4#803005)