WIP: added :DATASET to ext_out

src/pandablocks_ioc/_hdf_ioc.py

@@ -71,7 +71,7 @@ def __init__(
         status_message_setter: Callable,
         number_received_setter: Callable,
         number_captured_setter_pipeline: NumCapturedSetter,
-        dataset_name_cache: Dict[EpicsName, Dict[str, str]],
+        dataset_name_cache: Dict[str, Dict[str, str]],
     ):
         # Only one filename - user must stop capture and set new FileName/FilePath
         # for new files
@@ -334,7 +334,7 @@ class HDF5RecordController:
     def __init__(
         self,
         client: AsyncioClient,
-        dataset_name_cache: Dict[str, Callable[[str], str]],
+        dataset_name_cache: Dict[str, Dict[str, str]],
         record_prefix: str,
     ):
         if find_spec("h5py") is None:

src/pandablocks_ioc/_tables.py

@@ -81,7 +81,7 @@ def __init__(
     ):
         self.epics_table_name = epics_table_name
         self.pva_table_name = RecordName(epics_table_name)
-        self.rows = {}
+        self.rows: Dict[str, RecordWrapper] = {}
 
         block, field = self.epics_table_name.split(":", maxsplit=1)
 
@@ -124,12 +124,12 @@ def add_row(
         full_name = EpicsName(self.epics_table_name + ":" + row_name)
         pva_row_name = row_name.replace(":", "_").lower()
         length = length or len(initial_value)
-        initial_value = np.array(initial_value, dtype=datatype)
+        initial_value_np = np.array(initial_value, dtype=datatype)
 
         field_record: RecordWrapper = builder.WaveformIn(
             full_name,
             DESC="",  # Description not provided yet
-            initial_value=initial_value,
+            initial_value=initial_value_np,
             length=length,
         )
 

src/pandablocks_ioc/ioc.py

@@ -526,29 +526,25 @@ def update_cache(
         self.cache[field_name] = capture_names = {}
         # Only consider explicitly named datsets
         if dataset_name and capture_mode != "No":
-            # The last capture option is the one that should take the dataset name
+            # Keep a reference to just the dataset name for `DATA:DATASETS`
+            self._record_name_to_dataset_name[record_name] = dataset_name
             capture_names[capture_mode.split(" ")[-1]] = dataset_name
-            # But also suffix -min and -max if both are present
+            # Suffix -min and -max if both are present
             if "Min Max" in capture_mode:
                 capture_names["Min"] = f"{dataset_name}-min"
                 capture_names["Max"] = f"{dataset_name}-min"
 
-            self._record_name_to_dataset_name[record_name] = dataset_name
         else:
             self._record_name_to_dataset_name.pop(record_name, None)
 
         self.update_dataset_name_to_type()
 
     def update_dataset_name_to_type(self):
-        self._datasets_table.update_row(
-            "Name", list(self._record_name_to_dataset_name.values())
-        )
+        dataset_name_list = list(self._record_name_to_dataset_name.values())
+        self._datasets_table.update_row("Name", dataset_name_list)
         self._datasets_table.update_row(
             "Type",
-            [
-                "uint32" if "EXT_OUT" in record_name else "float64"
-                for record_name in self._record_name_to_dataset_name.keys()
-            ],
+            ["float64"] * len(dataset_name_list),
         )
 
 
@@ -1062,16 +1058,30 @@ def _make_ext_out(
         record_dict: Dict[EpicsName, RecordInfo] = {}
 
         # There is no record for the ext_out field itself - the only thing
-        # you do with them is to turn their Capture attribute on/off.
-        # The field itself has no value.
+        # you do with them is to turn their Capture attribute on/off, and give it
+        # an alternative dataset name
 
         capture_record_name = EpicsName(record_name + ":CAPTURE")
+        dataset_record_name = EpicsName(record_name + ":DATASET")
         labels, capture_index = self._process_labels(
             field_info.capture_labels, values[capture_record_name]
         )
+        record_dict[dataset_record_name] = self._create_record_info(
+            dataset_record_name,
+            "Used to adjust the dataset name to one more scientifically relevant",
+            builder.stringOut,
+            str,
+            PviGroup.OUTPUTS,
+            initial_value="",
+            on_update=lambda new_dataset_name: (
+                self._dataset_name_cache.update_cache(
+                    record_name,
+                    new_dataset_name,
+                    labels[record_dict[capture_record_name].record.get()],
+                )
+            ),
+        )
 
-        # TODO :DATASET on ext out, you don't need to add this to all
-        # position capture table, though we want it in `DATA:DATASETS`
         record_dict[capture_record_name] = self._create_record_info(
             capture_record_name,
             field_info.description,
@@ -1080,6 +1090,13 @@ def _make_ext_out(
             PviGroup.OUTPUTS,
             labels=labels,
             initial_value=capture_index,
+            on_update=lambda new_capture_mode: (
+                self._dataset_name_cache.update_cache(
+                    record_name,
+                    record_dict[dataset_record_name].record.get(),
+                    labels[new_capture_mode],
+                )
+            ),
         )
 
         return record_dict

tests/test_hdf_ioc.py

@@ -228,15 +228,13 @@ async def hdf5_controller(
 
     test_prefix, hdf5_test_prefix = new_random_hdf5_prefix
 
-    dataset_name_getters = {
-        "COUNTER1": lambda: "some_other_dataset_name",
+    dataset_name_cache = {
+        "COUNTER1.OUT": {"Value": "some_other_dataset_name"},
         # these datasets haven't been overwritten, they should be the default
-        "COUNTER2": lambda: "",
-        "COUNTER3": lambda: "",
     }
 
     hdf5_controller = HDF5RecordController(
-        AsyncioClient("localhost"), dataset_name_getters, test_prefix
+        AsyncioClient("localhost"), dataset_name_cache, test_prefix
     )
 
     # When using tests w/o CA, need to manually set _directory_exists to 1

tests/test_ioc.py

@@ -219,18 +219,19 @@ def idfn(val):
             ),
             {
                 f"{TEST_RECORD}:CAPTURE": "Diff",
+                f"{TEST_RECORD}:DATASET": "MyDataset",
             },
-            [
-                f"{TEST_RECORD}:CAPTURE",
-            ],
+            [f"{TEST_RECORD}:CAPTURE", f"{TEST_RECORD}:DATASET"],
         ),
         (
             ExtOutFieldInfo("ext_out", "samples", None, capture_labels=["No", "Diff"]),
             {
                 f"{TEST_RECORD}:CAPTURE": "Diff",
+                f"{TEST_RECORD}:DATASET": "MyDataset",
             },
             [
                 f"{TEST_RECORD}:CAPTURE",
+                f"{TEST_RECORD}:DATASET",
             ],
         ),
         (