wip: try to figure out how to use numtracker correctly

Author: ZohebShaikh

src/blueapi/utils/path_provider.py

@@ -38,22 +38,32 @@ def __call__(self, device_name: str | None = None) -> PathInfo:
         example: "detector_file_template": "custom-{device_name}-{scan_id}".
 
         If you do not provide a data_session_directory it will default to "/tmp".
+
+        If the start document has a scan_file in a subdirectory of the data session
+        directory (e.g. "sample1/ixx-1234"), detector files are written alongside it
+        in that subdirectory, which is created if it does not exist.
         """
         if not self._docs:
             raise BlueskyRunStructureError(
                 "Start document not found. This call must be made inside a run."
             )
         else:
-            template = self._docs[-1].get("detector_file_template")
+            doc = self._docs[-1]
+            template = doc.get("detector_file_template")
             if not template:
                 raise ValueError("detector_file_template must be set in metadata")
-            sub_path = template.format_map(
-                self._docs[-1] | {"device_name": device_name}
-            )
-            data_session_directory = Path(
-                self._docs[-1].get("data_session_directory", "/tmp")
+            sub_path = template.format_map(doc | {"device_name": device_name})
+            data_session_directory = Path(doc.get("data_session_directory", "/tmp"))
+            # numtracker's scan_file is relative to data_session_directory, write
+            # detector files in the same directory as it ("." if there is no
+            # scan_file or it has no subdirectory)
+            scan_file_directory = Path(doc.get("scan_file", "")).parent
+            return PathInfo(
+                directory_path=data_session_directory / scan_file_directory,
+                filename=sub_path,
+                # Negative depth creates only the directories scan_file adds
+                create_dir_depth=-len(scan_file_directory.parts),
             )
-            return PathInfo(directory_path=data_session_directory, filename=sub_path)
 
 
 class BlueskyRunStructureError(Exception):

tests/system_tests/test_blueapi_system.py

@@ -681,10 +681,13 @@ def on_event(event: AnyEvent) -> None:
 @pytest.mark.usefixtures("numtracker_with_subdirectory")
 def test_plan_runs_with_subdirectory(client_with_stomp: BlueapiClient, scan_id: int):
     start = Queue(maxsize=1)
+    stream_resources = Queue()
 
     def on_event(event: AnyEvent) -> None:
         if isinstance(event, DataEvent) and event.name == "start":
             start.put_nowait(event.doc)
+        if isinstance(event, DataEvent) and event.name == "stream_resource":
+            stream_resources.put_nowait(event.doc)
 
     cb_id = client_with_stomp.add_callback(on_event)
     try:
@@ -700,6 +703,9 @@ def on_event(event: AnyEvent) -> None:
     assert start_doc["data_session_subdirectory"] == "sample1"
     assert start_doc["data_session_directory"] == "/tmp"
     assert start_doc["scan_file"] == f"sample1/adsim-{scan_id}"
+    # Detector files are written alongside the scan file, in the subdirectory
+    resource = stream_resources.get_nowait()
+    assert resource["uri"].endswith(f"/tmp/sample1/adsim-{scan_id}-det.h5")
 
 
 @pytest.mark.parametrize(

tests/unit_tests/utils/test_path_provider.py

@@ -52,6 +52,33 @@ def test_start_document_path_provider_with_default_template_returns_correct_path
     )
 
 
+@pytest.mark.parametrize(
+    "scan_file,directory,create_dir_depth",
+    [
+        ("p01-22", "/p01/ab123", 0),
+        ("sample1/p01-22", "/p01/ab123/sample1", -1),
+        ("sample1/calibration/p01-22", "/p01/ab123/sample1/calibration", -2),
+    ],
+)
+def test_start_document_path_provider_writes_alongside_scan_file(
+    start_doc_default_template: dict,
+    scan_file: str,
+    directory: str,
+    create_dir_depth: int,
+):
+    pp = StartDocumentPathProvider()
+    pp.run_start(
+        name="start",
+        start_document=start_doc_default_template | {"scan_file": scan_file},  # type: ignore
+    )
+
+    assert pp("det") == PathInfo(
+        directory_path=PosixPath(directory),
+        filename="p01-22-det",
+        create_dir_depth=create_dir_depth,
+    )
+
+
 @pytest.fixture
 def start_doc_custom_template() -> dict:
     return {