fix: use create_api_app in OrchestrationClient to prevent read-only container failures

src/prefect/server/api/clients.py

@@ -31,13 +31,13 @@ class BaseClient:
     _http_client: PrefectHttpxAsyncClient
 
     def __init__(self, additional_headers: dict[str, str] | None = None):
-        from prefect.server.api.server import create_app
+        from prefect.server.api.server import create_api_app
 
         additional_headers = additional_headers or {}
 
-        # create_app caches application instances, and invoking it with no arguments
-        # will point it to the the currently running server instance
-        api_app = create_app()
+        # create_api_app creates only the API routes without UI or background
+        # services, which is all OrchestrationClient needs for in-process calls.
+        api_app = create_api_app()
 
         settings = get_current_settings()
 

src/prefect/server/events/actions.py

@@ -1811,6 +1811,13 @@ async def message_handler(message: Message):
         except ActionFailed as e:
             # ActionFailed errors are expected errors and will not be retried
             await action.fail(triggered_action, e.reason)
+        except Exception:
+            logger.exception(
+                "Unexpected error executing action %s for automation %s",
+                triggered_action.id,
+                triggered_action.automation.id,
+            )
+            raise
         else:
             await action.succeed(triggered_action)
             await record_action_happening(triggered_action.id)

tests/server/api/test_clients.py

@@ -12,7 +12,7 @@
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from prefect.server.api.clients import OrchestrationClient
-from prefect.server.api.server import create_app
+from prefect.server.api.server import create_api_app, create_app
 from prefect.server.models import deployments, flow_runs, flows
 from prefect.server.models.variables import create_variable
 from prefect.server.schemas.actions import VariableCreate
@@ -260,6 +260,20 @@ async def test_read_variables_with_error(orchestration_client: OrchestrationClie
             await orchestration_client.read_workspace_variables()
 
 
+async def test_orchestration_client_uses_api_app():
+    """
+    Regression test for https://github.com/PrefectHQ/prefect/issues/19317
+
+    OrchestrationClient should use create_api_app instead of create_app to avoid
+    UI static file creation and background services that fail in read-only containers.
+    """
+    with mock.patch(
+        "prefect.server.api.server.create_api_app", wraps=create_api_app
+    ) as mock_create_api_app:
+        OrchestrationClient()
+        mock_create_api_app.assert_called_once()
+
+
 async def test_get_orchestration_client_after_create_app_final():
     """
     Regression test for https://github.com/PrefectHQ/prefect/issues/17451