Merge branch 'rename-s2'

backend/fluksio/api/routes/flows.py

@@ -65,7 +65,7 @@ from fluksio.flow.devices import (
 from fluksio.flow.events import event_bus
 from fluksio.flow.messages import MEDIA_FAMILIES, DType, flow_of, qualify
 from fluksio.flow.nodes.wren import TRAIN_FLOW, WrenNode, pack_meta
-from fluksio.flow.pipeline import ValidationIssue
+from fluksio.flow.pipeline import EngineHeld, ValidationIssue
 from fluksio.flow.runs import RunRejected
 from fluksio.flow.schemas import (
     NAME_PATTERN,
@@ -1558,6 +1558,7 @@ FRAME_REFUSALS = {
     "not_scalar": "the port it names is not wired as a bool, int, float or str",
     "undeclared": "no flow declares its message",
     "refused": "its message refused the value",
+    "busy": "a rename holds the engine",
 }
 
 
@@ -1604,6 +1605,8 @@ def ingest_frame(app: Any, device: DeviceDef, data: bytes) -> str:
         return "undeclared"
     except TypeError:
         return "refused"
+    except EngineHeld:
+        return "busy"
     return ""
 
 
@@ -1657,6 +1660,8 @@ def ingest_publish(app: Any, device: DeviceDef, payload: dict[str, Any]) -> str:
         return "undeclared"
     except TypeError:
         return "refused"
+    except EngineHeld:
+        return "busy"
     return ""