Structure endpoint attach downstream asset to task level (#51401)

pierrejeambrun · web-flow · commit 14ee1f4f6001 · 2025-06-05T11:28:58.000+02:00
* Attach downstream assets to task

* Adjust tests
diff --git a/airflow-core/src/airflow/api_fastapi/core_api/routes/ui/structure.py b/airflow-core/src/airflow/api_fastapi/core_api/routes/ui/structure.py
@@ -26,7 +26,10 @@
 from airflow.api_fastapi.core_api.datamodels.ui.structure import StructureDataResponse
 from airflow.api_fastapi.core_api.openapi.exceptions import create_openapi_http_exception_doc
 from airflow.api_fastapi.core_api.security import requires_access_dag
-from airflow.api_fastapi.core_api.services.ui.structure import get_upstream_assets
+from airflow.api_fastapi.core_api.services.ui.structure import (
+    bind_output_assets_to_tasks,
+    get_upstream_assets,
+)
 from airflow.models.dag_version import DagVersion
 from airflow.models.serialized_dag import SerializedDagModel
 from airflow.utils.dag_edges import dag_edges
@@ -139,4 +142,6 @@ def structure_data(
 
         data["edges"] += start_edges + edges + end_edges
 
+    bind_output_assets_to_tasks(data["edges"], serialized_dag)
+
     return StructureDataResponse(**data)
diff --git a/airflow-core/src/airflow/api_fastapi/core_api/services/ui/structure.py b/airflow-core/src/airflow/api_fastapi/core_api/services/ui/structure.py
@@ -23,6 +23,8 @@
 
 from __future__ import annotations
 
+from airflow.models.serialized_dag import SerializedDagModel
+
 
 def get_upstream_assets(
     asset_expression: dict, entry_node_ref: str, level: int = 0
@@ -112,3 +114,32 @@ def get_upstream_assets(
             edges = edges + e
 
     return nodes, edges
+
+
+def bind_output_assets_to_tasks(edges: list[dict], serialized_dag: SerializedDagModel) -> None:
+    """
+    Try to bind the downstream assets to the relevant task that produces them.
+
+    This function will mutate the `edges` in place.
+    """
+    outlet_asset_references = serialized_dag.dag_model.task_outlet_asset_references
+
+    downstream_asset_related_edges = [edge for edge in edges if edge["target_id"].startswith("asset:")]
+
+    for edge in downstream_asset_related_edges:
+        asset_id = int(edge["target_id"].strip("asset:"))
+        try:
+            # Try to attach the outlet asset to the relevant task
+            outlet_asset_reference = next(
+                outlet_asset_reference
+                for outlet_asset_reference in outlet_asset_references
+                if outlet_asset_reference.asset_id == asset_id
+            )
+            edge["source_id"] = outlet_asset_reference.task_id
+            continue
+        except StopIteration:
+            # If no asset reference found, fallback to using the exit node reference
+            # This can happen because asset aliases are not yet handled, they do no populate
+            # the `outlet_asset_references` when resolved. Extra lookup is needed. Same for asset-name-ref and
+            # asset-uri-ref.
+            pass
diff --git a/airflow-core/tests/unit/api_fastapi/core_api/routes/ui/test_structure.py b/airflow-core/tests/unit/api_fastapi/core_api/routes/ui/test_structure.py
@@ -369,7 +369,7 @@ def test_should_return_200_with_asset(self, test_client, asset1_id, asset2_id, a
                 {
                     "is_setup_teardown": None,
                     "label": None,
-                    "source_id": "task_2",
+                    "source_id": "task_1",
                     "target_id": f"asset:{asset3_id}",
                     "is_source_asset": None,
                 },

Original file line number	Diff line number	Diff line change
`@@ -369,7 +369,7 @@ def test_should_return_200_with_asset(self, test_client, asset1_id, asset2_id, a`
`369`	`369`	`{`
`370`	`370`	`"is_setup_teardown": None,`
`371`	`371`	`"label": None,`
`372`		`- "source_id": "task_2",`
	`372`	`+ "source_id": "task_1",`
`373`	`373`	`"target_id": f"asset:{asset3_id}",`
`374`	`374`	`"is_source_asset": None,`
`375`	`375`	`},`