Setup PandA writer to set create directory depth PV on open (#503)

* Add support for directory creation feature in PandA

* Update tests to reflect create_directory changes

* Make sure create_dir_depth is set before directory_path

* Adding test case for when directory does not exist panda writer

* Directory exists record should be a bool

* Cast dir path to string to avoid p4p error

* Fix failing test

* Fix typo leftover from merge conflict resolution

src/ophyd_async/fastcs/panda/_block.py

@@ -13,6 +13,8 @@ class DataBlock(Device):
     hdf_file_name: SignalRW[str]
     num_capture: SignalRW[int]
     num_captured: SignalR[int]
+    create_directory: SignalRW[int]
+    directory_exists: SignalR[bool]
     capture: SignalRW[bool]
     flush_period: SignalRW[float]
     datasets: SignalR[DatasetTable]

src/ophyd_async/fastcs/panda/_writer.py

@@ -46,17 +46,27 @@ async def open(self, multiplier: int = 1) -> Dict[str, DataKey]:
 
         self._file = None
         info = self._path_provider(device_name=self._name_provider())
+
+        # Set create dir depth first to guarantee that callback when setting
+        # directory path has correct value
+        await self.panda_data_block.create_directory.set(info.create_dir_depth)
+
         # Set the initial values
         await asyncio.gather(
-            self.panda_data_block.hdf_directory.set(info.directory_path),
+            self.panda_data_block.hdf_directory.set(str(info.directory_path)),
             self.panda_data_block.hdf_file_name.set(
                 f"{info.filename}.h5",
             ),
             self.panda_data_block.num_capture.set(0),
-            # TODO: Set create_dir_depth once available
-            # https://github.com/bluesky/ophyd-async/issues/317
         )
 
+        # Make sure that directory exists or has been created.
+        if not await self.panda_data_block.directory_exists.get_value() == 1:
+            raise OSError(
+                f"Directory {info.directory_path} does not exist or "
+                "is not writable by the PandABlocks-ioc!"
+            )
+
         # Wait for it to start, stashing the status that tells us when it finishes
         await self.panda_data_block.capture.set(True)
         if multiplier > 1:

tests/fastcs/panda/test_hdf_panda.py

@@ -1,3 +1,4 @@
+import os
 from typing import Dict
 from unittest.mock import ANY
 
@@ -41,7 +42,13 @@ class CaptureBlock(Device):
     def link_function(value, **kwargs):
         set_mock_value(mock_hdf_panda.pcap.active, value)
 
+    # Mimic directory exists check that happens normally in the PandA IOC
+    def check_dir_exits(value, **kwargs):
+        if os.path.exists(value):
+            set_mock_value(mock_hdf_panda.data.directory_exists, 1)
+
     callback_on_mock_put(mock_hdf_panda.pcap.arm, link_function)
+    callback_on_mock_put(mock_hdf_panda.data.hdf_directory, check_dir_exits)
 
     set_mock_value(
         mock_hdf_panda.data.datasets,

tests/fastcs/panda/test_panda_utils.py

@@ -50,6 +50,7 @@ async def test_save_panda(mock_save_to_yaml, mock_panda, RE: RunEngine):
             },
             {
                 "data.capture": False,
+                "data.create_directory": 0,
                 "data.flush_period": 0.0,
                 "data.hdf_directory": "",
                 "data.hdf_file_name": "",

tests/fastcs/panda/test_writer.py

@@ -1,3 +1,4 @@
+import os
 from pathlib import Path
 from unittest.mock import ANY
 
@@ -14,6 +15,9 @@
     StaticPathProvider,
     set_mock_value,
 )
+from ophyd_async.core._mock_signal_utils import (
+    callback_on_mock_put,
+)
 from ophyd_async.epics.pvi import create_children_from_annotations, fill_pvi_entries
 from ophyd_async.fastcs.panda import (
     CommonPandaBlocks,
@@ -84,6 +88,14 @@ async def mock_panda(panda_t):
     async with DeviceCollector(mock=True):
         mock_panda = panda_t("mock_PANDA", name="mock_panda")
 
+    # Mimic directory exists check that happens normally in the PandA IOC
+    def check_dir_exits(value, **kwargs):
+        if os.path.exists(os.path.abspath(os.path.dirname(value))):
+            set_mock_value(mock_panda.data.directory_exists, 1)
+
+    # Assume directory exists
+    callback_on_mock_put(mock_panda.data.hdf_directory, check_dir_exits)
+
     set_mock_value(
         mock_panda.data.datasets,
         DatasetTable(
@@ -98,7 +110,7 @@ async def mock_panda(panda_t):
 @pytest.fixture
 async def mock_writer(tmp_path, mock_panda) -> PandaHDFWriter:
     fp = StaticFilenameProvider("data")
-    dp = StaticPathProvider(fp, tmp_path / mock_panda.name)
+    dp = StaticPathProvider(fp, tmp_path / mock_panda.name, create_dir_depth=-1)
     async with DeviceCollector(mock=True):
         writer = PandaHDFWriter(
             prefix="TEST-PANDA",
@@ -146,7 +158,7 @@ async def test_open_close_sets_capture(mock_writer: PandaHDFWriter):
 async def test_open_sets_file_path_and_name(mock_writer: PandaHDFWriter, tmp_path):
     await mock_writer.open()
     path = await mock_writer.panda_data_block.hdf_directory.get_value()
-    assert path == tmp_path / mock_writer._name_provider()
+    assert path == str(tmp_path / mock_writer._name_provider())
     name = await mock_writer.panda_data_block.hdf_file_name.get_value()
     assert name == "data.h5"
 
@@ -204,3 +216,20 @@ def assert_resource_document(name, resource_doc):
         assert_resource_document(name=name, resource_doc=resource_doc)
 
         assert resource_doc["data_key"] == name
+
+
+async def test_oserror_when_hdf_dir_does_not_exist(tmp_path, mock_panda):
+    fp = StaticFilenameProvider("data")
+    dp = StaticPathProvider(
+        fp, tmp_path / mock_panda.name / "extra" / "dirs", create_dir_depth=-1
+    )
+    async with DeviceCollector(mock=True):
+        writer = PandaHDFWriter(
+            prefix="TEST-PANDA",
+            path_provider=dp,
+            name_provider=lambda: "test-panda",
+            panda_data_block=mock_panda.data,
+        )
+
+    with pytest.raises(OSError):
+        await writer.open()