Make attach_data_session_metadata_wrapper a no-op if there is no path provider (#1192)

Author: abbiemery

src/dodal/common/beamlines/beamline_utils.py

@@ -162,3 +162,8 @@ def set_path_provider(provider: PathProvider):
 
 def get_path_provider() -> PathProvider:
     return PATH_PROVIDER
+
+
+def clear_path_provider() -> None:
+    global PATH_PROVIDER
+    del PATH_PROVIDER

src/dodal/plan_stubs/data_session.py

@@ -33,14 +33,23 @@ def attach_data_session_metadata_wrapper(
     Yields:
         Iterator[Msg]: Plan messages
     """
-    provider = provider or get_path_provider()
+    try:
+        provider = provider or get_path_provider()
+    except NameError:
+        provider = None
+
     if isinstance(provider, UpdatingPathProvider):
         yield from bps.wait_for([provider.update])
         ress = yield from bps.wait_for([provider.data_session])
         data_session = ress[0].result()
         # https://github.com/DiamondLightSource/dodal/issues/452
         # As part of 452, write each dataCollection into their own folder, then can use resource_dir directly
         yield from bpp.inject_md_wrapper(plan, md={DATA_SESSION: data_session})
+    elif provider is None:
+        logging.warning(
+            f"There is no PathProvider set, {attach_data_session_metadata_wrapper.__name__} will have no effect"
+        )
+        yield from plan
     else:
         logging.warning(
             f"{provider} is not an UpdatingPathProvider, {attach_data_session_metadata_wrapper.__name__} will have no effect"

tests/plan_stubs/test_data_session.py

@@ -3,6 +3,7 @@
 from bluesky.run_engine import RunEngine
 from bluesky.utils import MsgGenerator
 
+from dodal.common.beamlines.beamline_utils import clear_path_provider
 from dodal.plan_stubs.data_session import attach_data_session_metadata_wrapper
 
 
@@ -20,3 +21,16 @@ def fake_plan() -> MsgGenerator[None]:
         f"{path_provider} is not an UpdatingPathProvider, {attach_data_session_metadata_wrapper.__name__} will have no effect"
         in caplog.text
     )
+
+
+def test_attach_data_session_metadata_wrapper_with_no_provider_is_noop(
+    caplog, RE: RunEngine
+):
+    def fake_plan() -> MsgGenerator[None]:
+        yield from []
+
+    clear_path_provider()
+    plan = attach_data_session_metadata_wrapper(plan=fake_plan())
+    RE(plan)
+
+    assert f"There is no PathProvider set, {attach_data_session_metadata_wrapper.__name__} will have no effect"