AIP-66: Add support for parsing DAG bundles (#45371)

Let's start parsing DAG bundles! This moves us away from parsing a
single local directory to being able to parse many different bundles,
including optional support for versioning.

This is just the basics - it keeps the parsing loop largely untouched.
We still have a single list of "dag files" to parse, and queue of them.
However, instead of just a path, this list and queue now contain
`DagFilePath`s, which hold both a local path and the bundle its from.

There are a number of things that are not fully functional at this
stage, like versioned callbacks. These will be refactored later. There
is enough churn with the basics (particularly with the number of test
changes).

Co-authored-by: Daniel Standish <[email protected]>

airflow/cli/commands/local_commands/dag_processor_command.py

@@ -39,7 +39,6 @@ def _create_dag_processor_job_runner(args: Any) -> DagProcessorJobRunner:
         job=Job(),
         processor=DagFileProcessorManager(
             processor_timeout=processor_timeout_seconds,
-            dag_directory=args.subdir,
             max_runs=args.num_runs,
         ),
     )

airflow/dag_processing/bundles/manager.py

@@ -64,6 +64,23 @@ def parse_config(self) -> None:
                 "Bundle config is not a list. Check config value"
                 " for section `dag_bundles` and key `backends`."
             )
+
+        # example dags!
+        if conf.getboolean("core", "LOAD_EXAMPLES"):
+            from airflow import example_dags
+
+            example_dag_folder = next(iter(example_dags.__path__))
+            backends.append(
+                {
+                    "name": "example_dags",
+                    "classpath": "airflow.dag_processing.bundles.local.LocalDagBundle",
+                    "kwargs": {
+                        "local_folder": example_dag_folder,
+                        "refresh_interval": conf.getint("scheduler", "dag_dir_list_interval"),
+                    },
+                }
+            )
+
         seen = set()
         for cfg in backends:
             name = cfg["name"]

airflow/dag_processing/collection.py

@@ -74,11 +74,14 @@
 log = logging.getLogger(__name__)
 
 
-def _create_orm_dags(dags: Iterable[MaybeSerializedDAG], *, session: Session) -> Iterator[DagModel]:
+def _create_orm_dags(
+    bundle_name: str, dags: Iterable[MaybeSerializedDAG], *, session: Session
+) -> Iterator[DagModel]:
     for dag in dags:
         orm_dag = DagModel(dag_id=dag.dag_id)
         if dag.is_paused_upon_creation is not None:
             orm_dag.is_paused = dag.is_paused_upon_creation
+        orm_dag.bundle_name = bundle_name
         log.info("Creating ORM DAG for %s", dag.dag_id)
         session.add(orm_dag)
         yield orm_dag
@@ -270,6 +273,8 @@ def _update_import_errors(files_parsed: set[str], import_errors: dict[str, str],
 
 
 def update_dag_parsing_results_in_db(
+    bundle_name: str,
+    bundle_version: str | None,
     dags: Collection[MaybeSerializedDAG],
     import_errors: dict[str, str],
     warnings: set[DagWarning],
@@ -307,7 +312,7 @@ def update_dag_parsing_results_in_db(
             )
             log.debug("Calling the DAG.bulk_sync_to_db method")
             try:
-                DAG.bulk_write_to_db(dags, session=session)
+                DAG.bulk_write_to_db(bundle_name, bundle_version, dags, session=session)
                 # Write Serialized DAGs to DB, capturing errors
                 # Write Serialized DAGs to DB, capturing errors
                 for dag in dags:
@@ -346,6 +351,8 @@ class DagModelOperation(NamedTuple):
     """Collect DAG objects and perform database operations for them."""
 
     dags: dict[str, MaybeSerializedDAG]
+    bundle_name: str
+    bundle_version: str | None
 
     def find_orm_dags(self, *, session: Session) -> dict[str, DagModel]:
         """Find existing DagModel objects from DAG objects."""
@@ -365,7 +372,8 @@ def add_dags(self, *, session: Session) -> dict[str, DagModel]:
         orm_dags.update(
             (model.dag_id, model)
             for model in _create_orm_dags(
-                (dag for dag_id, dag in self.dags.items() if dag_id not in orm_dags),
+                bundle_name=self.bundle_name,
+                dags=(dag for dag_id, dag in self.dags.items() if dag_id not in orm_dags),
                 session=session,
             )
         )
@@ -430,6 +438,8 @@ def update_dags(
             dm.timetable_summary = dag.timetable.summary
             dm.timetable_description = dag.timetable.description
             dm.asset_expression = dag.timetable.asset_condition.as_expression()
+            dm.bundle_name = self.bundle_name
+            dm.latest_bundle_version = self.bundle_version
 
             last_automated_run: DagRun | None = run_info.latest_runs.get(dag.dag_id)
             if last_automated_run is None: