fix(scan): extract user metadata for direct scans in ScanAssembler

Author: wakonig

bec_server/bec_server/scan_server/scan_assembler.py

@@ -129,12 +129,16 @@ def assemble_direct_scan(
             scan_cls, scan_info["signature"], resolved_args, resolved_kwargs
         )
 
+        metadata = msg.metadata.copy() if msg.metadata is not None else None
+        user_metadata = metadata.pop("user_metadata", {}) if metadata is not None else {}
+
         scan_instance = scan_cls(
             *resolved_args,
             device_manager=self.device_manager,
             redis_connector=self.connector,
             scan_modifier=get_scan_modifier(),
-            metadata=msg.metadata,
+            metadata=metadata,
+            user_metadata=user_metadata,
             instruction_handler=self.parent.queue_manager.instruction_handler,
             scan_id=scan_id,
             request_inputs=request_inputs,

bec_server/tests/tests_scan_server/test_scan_assembler.py

@@ -726,3 +726,28 @@ class MockScanManager:
         "burst_at_each_point": 3,
         "system_config": {"file_directory": "/tmp/data"},
     }
+
+
+def test_scan_assembler_extracts_user_metadata_for_direct_scans(dm_with_devices):
+    parent = mock.MagicMock()
+    parent.device_manager = dm_with_devices
+    parent.connector = mock.MagicMock()
+    parent.queue_manager.instruction_handler = mock.MagicMock()
+    assembler = ScanAssembler(parent=parent)
+
+    class MockScanManager:
+        scan_dict = {"_v4_acquire": Acquire}
+
+    msg = messages.ScanQueueMessage(
+        scan_type="_v4_acquire",
+        parameter={"args": [], "kwargs": {"exp_time": 0.2, "system_config": {}}},
+        queue="primary",
+        metadata={"RID": "rid-123", "user_metadata": {"sample": "my_sample"}},
+    )
+
+    with mock.patch.object(assembler, "scan_manager", MockScanManager()):
+        request = assembler.assemble_direct_scan(msg, "scan_id")
+
+    assert request.scan_info.metadata == {"RID": "rid-123"}
+    assert request.scan_info.user_metadata == {"sample": "my_sample"}
+    assert msg.metadata == {"RID": "rid-123", "user_metadata": {"sample": "my_sample"}}