[Cloud Composer] Update maintenance DAG - DagRun additional filter (#13307)

* Adding missing filter of Externally Triggered DagRuns when cleaning Airflow metadata database.

* Remove blank line - lint.

* Update removing manual executions. We dont want to skip them.

* Adding a comment as to what we are removing/

* Rewrite comments.

* Skip nox for Python3.13 as it is not suported by AF.
;

Author: apilaskowski

composer/workflows/airflow_db_cleanup.py

@@ -338,10 +338,12 @@ def build_query(
         query = query.filter(airflow_db_model.dag_id == dag_id)
 
     if airflow_db_model == DagRun:
-        # For DaRus we want to leave last DagRun regardless of its age
+        # For DagRuns we want to leave last *scheduled* DagRun
+        # regardless of its age
         newest_dagrun = (
             session
             .query(airflow_db_model)
+            .filter(DagRun.external_trigger.is_(False))
             .filter(airflow_db_model.dag_id == dag_id)
             .order_by(desc(airflow_db_model.execution_date))
             .first()
@@ -350,7 +352,6 @@ def build_query(
         if newest_dagrun is not None:
             query = (
                 query
-                .filter(DagRun.external_trigger.is_(False))
                 .filter(age_check_column <= max_date)
                 .filter(airflow_db_model.id != newest_dagrun.id)
             )

composer/workflows/noxfile_config.py

@@ -38,6 +38,7 @@
         "3.9",
         "3.10",
         "3.12",
+        "3.13",
     ],  # Composer w/ Airflow 2 only supports Python 3.8
     # Old samples are opted out of enforcing Python type hints
     # All new samples should feature them