Add task_acks_late configuration to Celery Executor

airflow/providers/celery/executors/default_celery.py

@@ -72,7 +72,7 @@ def _broker_supports_visibility_timeout(url):
     "accept_content": ["json"],
     "event_serializer": "json",
     "worker_prefetch_multiplier": conf.getint("celery", "worker_prefetch_multiplier", fallback=1),
-    "task_acks_late": True,
+    "task_acks_late": conf.getboolean("celery", "task_acks_late", fallback=True),
     "task_default_queue": conf.get("operators", "DEFAULT_QUEUE"),
     "task_default_exchange": conf.get("operators", "DEFAULT_QUEUE"),
     "task_track_started": conf.getboolean("celery", "task_track_started", fallback=True),

airflow/providers/celery/provider.yaml

@@ -276,6 +276,21 @@ config:
         type: float
         example: ~
         default: "1.0"
+      task_acks_late:
+        description: |
+          If an Airflow task's execution time exceeds the visibility_timeout, Celery will re-assign the
+          task to a Celery worker, even if the original task is still running successfully. The new task
+          instance then runs concurrently with the original task and the Airflow UI and logs only show an
+          error message:
+          'Task Instance Not Running' FAILED: Task is in the running state'
+          Setting task_acks_late to True will force Celery to wait until a task is finished before a
+          new task instance is assigned. This effectively overrides the visibility timeout.
+          See also:
+          https://docs.celeryq.dev/en/stable/reference/celery.app.task.html#celery.app.task.Task.acks_late
+        version_added: 2.9.0
+        type: boolean
+        example: "True"
+        default: "True"
       task_track_started:
         description: |
           Celery task will report its status as 'started' when the task is executed by a worker.

docs/spelling_wordlist.txt

@@ -7,6 +7,7 @@ Ack
 ack
 ackIds
 acknowledgement
+acks
 actionCard
 Acyclic
 acyclic

tests/providers/celery/executors/test_celery_executor.py

@@ -358,3 +358,12 @@ def test_sentinel_kwargs_loaded_from_string():
     assert default_celery.DEFAULT_CELERY_CONFIG["broker_transport_options"]["sentinel_kwargs"] == {
         "service_name": "mymaster"
     }
+
+
+@conf_vars({("celery", "task_acks_late"): "False"})
+def test_celery_task_acks_late_loaded_from_string():
+    import importlib
+
+    # reload celery conf to apply the new config
+    importlib.reload(default_celery)
+    assert default_celery.DEFAULT_CELERY_CONFIG["task_acks_late"] is False