ExternalTaskSensor can never find External Parent Task

Apache Airflow version: 2.0

Kubernetes version (if you are using kubernetes) (use kubectl version): 1.18

Environment: Linux

• Cloud provider or hardware configuration: AWS
• OS (e.g. from /etc/os-release): Linux
• Kernel (e.g. uname -a):
• Install tools:
• Others:

What happened: Following the example below https://github.com/apache/airflow/blob/master/airflow/example_dags/example_external_task_marker_dag.py, when you trigger the parent task, it succeeds so then you trigger the child task it goes into reschedule loop until it times out because the execution date filter is only single list object of the child execution task which wont ever be the same as the parent. https://github.com/apache/airflow/blob/master/airflow/sensors/external_task.py#L216

IRFLOW_CTX_DAG_OWNER=airflow
AIRFLOW_CTX_DAG_ID=example_external_task_marker_child
AIRFLOW_CTX_TASK_ID=child_task1
AIRFLOW_CTX_EXECUTION_DATE=2021-01-14T17:33:14.178268+00:00
AIRFLOW_CTX_DAG_RUN_ID=manual__2021-01-14T17:33:14.178268+00:00
[2021-01-14 17:33:49,750] {external_task.py:153} INFO - Poking for example_external_task_marker_parent.parent_task on 2021-01-14T17:33:14.178268+00:00 ... 
[2021-01-14 17:33:49,889] {taskinstance.py:1386} INFO - Rescheduling task, marking task as UP_FOR_RESCHEDULE
[2021-01-14 17:33:49,928] {local_task_job.py:118} INFO - Task exited with return code 0
[2021-01-14 17:35:22,581] {taskinstance.py:826} INFO - Dependencies all met for <TaskInstance: example_external_task_marker_child.child_task1 2021-01-14T17:33:14.178268+00:00 [queued]>
[2021-01-14 17:35:22,626] {taskinstance.py:826} INFO - Dependencies all met for <TaskInstance: example_external_task_marker_child.child_task1 2021-01-14T17:33:14.178268+00:00 [queued]>
[2021-01-14 17:35:22,627] {taskinstance.py:1017} INFO - 
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[2021-01-14 17:35:22,627] {taskinstance.py:1018} INFO - Starting attempt 1 of 1
[2021-01-14 17:35:22,627] {taskinstance.py:1019} INFO - 
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[2021-01-14 17:35:22,657] {taskinstance.py:1038} INFO - Executing <Task(ExternalTaskSensor): child_task1> on 2021-01-14T17:33:14.178268+00:00
[2021-01-14 17:35:22,665] {standard_task_runner.py:51} INFO - Started process 24 to run task
[2021-01-14 17:35:22,678] {standard_task_runner.py:75} INFO - Running: ['airflow', 'tasks', 'run', 'example_external_task_marker_child', 'child_task1', '2021-01-14T17:33:14.178268+00:00', '--job-id', '53', '--pool', 'default_pool', '--raw', '--subdir', 'DAGS_FOLDER/dags/examples/external_sensor.py', '--cfg-path', '/tmp/tmpzb2z00at']
[2021-01-14 17:35:22,680] {standard_task_runner.py:76} INFO - Job 53: Subtask child_task1
[2021-01-14 17:35:22,881] {logging_mixin.py:103} INFO - Running <TaskInstance: example_external_task_marker_child.child_task1 2021-01-14T17:33:14.178268+00:00 [running]> on host exampleexternaltaskmarkerchildchildtask1-e6a0f9157da74583bb7373
[2021-01-14 17:35:23,667] {taskinstance.py:1230} INFO - Exporting the following env vars:
AIRFLOW_CTX_DAG_OWNER=airflow
AIRFLOW_CTX_DAG_ID=example_external_task_marker_child
AIRFLOW_CTX_TASK_ID=child_task1
AIRFLOW_CTX_EXECUTION_DATE=2021-01-14T17:33:14.178268+00:00
AIRFLOW_CTX_DAG_RUN_ID=manual__2021-01-14T17:33:14.178268+00:00
[2021-01-14 17:35:23,695] {external_task.py:153} INFO - Poking for example_external_task_marker_parent.parent_task on 2021-01-14T17:33:14.178268+00:00 ... 
[2021-01-14 17:35:23,833] {taskinstance.py:1386} INFO - Rescheduling task, marking task as UP_FOR_RESCHEDULE
[2021-01-14 17:35:23,852] {local_task_job.py:118} INFO - Task exited with return code 0
[2021-01-14 17:36:59,125] {taskinstance.py:826} INFO - Dependencies all met for <TaskInstance: example_external_task_marker_child.child_task1 2021-01-14T17:33:14.178268+00:00 [queued]>
[2021-01-14 17:36:59,172] {taskinstance.py:826} INFO - Dependencies all met for <TaskInstance: example_external_task_marker_child.child_task1 2021-01-14T17:33:14.178268+00:00 [queued]>
[2021-01-14 17:36:59,172] {taskinstance.py:1017} INFO - 

What you expected to happen: I would expect the filter to be a range not a single timestamp? Or we should be able to send in a date instead of a datetime?

How to reproduce it: Run this Example https://github.com/apache/airflow/blob/master/airflow/example_dags/example_external_task_marker_dag.py

Anything else we need to know:

[ephraimbuddy]

@ephraimbuddy is the issue here only fixing example dag ?

Yes. @eladkal

[eladkal]

@ephraimbuddy is the issue here only fixing example dag ?