Metric for raw task return codes (#27155)

Co-authored-by: Igor Kholopov <kholopovus@gmail.com>

airflow/jobs/local_task_job.py

@@ -157,6 +157,7 @@ def handle_task_exit(self, return_code: int) -> None:
         # Without setting this, heartbeat may get us
         self.terminating = True
         self.log.info("Task exited with return code %s", return_code)
+        self._log_return_code_metric(return_code)
 
         if not self.task_instance.test_mode:
             if conf.getboolean("scheduler", "schedule_after_task_execution", fallback=True):
@@ -225,6 +226,11 @@ def heartbeat_callback(self, session=None):
                 self.terminating = True
             self._state_change_checks += 1
 
+    def _log_return_code_metric(self, return_code: int):
+        Stats.incr(
+            f"local_task_job.task_exit.{self.id}.{self.dag_id}.{self.task_instance.task_id}.{return_code}"
+        )
+
     @staticmethod
     def _enable_task_listeners():
         """

tests/jobs/test_local_task_job.py

@@ -374,6 +374,28 @@ def test_localtaskjob_double_trigger(self):
 
         session.close()
 
+    @patch.object(StandardTaskRunner, "return_code")
+    @mock.patch("airflow.jobs.scheduler_job.Stats.incr", autospec=True)
+    def test_local_task_return_code_metric(self, mock_stats_incr, mock_return_code, create_dummy_dag):
+
+        _, task = create_dummy_dag("test_localtaskjob_code")
+
+        ti_run = TaskInstance(task=task, execution_date=DEFAULT_DATE)
+        ti_run.refresh_from_db()
+        job1 = LocalTaskJob(task_instance=ti_run, executor=SequentialExecutor())
+        job1.id = 95
+
+        mock_return_code.side_effect = [None, -9, None]
+
+        with timeout(10):
+            job1.run()
+
+        mock_stats_incr.assert_has_calls(
+            [
+                mock.call("local_task_job.task_exit.95.test_localtaskjob_code.op1.-9"),
+            ]
+        )
+
     @pytest.mark.quarantined
     @patch.object(StandardTaskRunner, "return_code")
     def test_localtaskjob_maintain_heart_rate(self, mock_return_code, caplog, create_dummy_dag):