Feature/list filled paths

docs/source/intro.rst

@@ -86,17 +86,6 @@ get an error message if this is not possible:
 Load and store an IDS to disk with IMAS-Core
 ''''''''''''''''''''''''''''''''''''''''''''
 
-.. note::
-
-    - This functionality requires the IMAS-Core, until this library is openly available
-      on GitHub you may need to fetch it from `git.iter.org <https://git.iter.org/>`_
-      (requires to have an ITER account). Using IMAS-Core also enable slicing methods
-      :py:meth:`~imas.db_entry.DBEntry.get_slice`, 
-      :py:meth:`~imas.db_entry.DBEntry.put_slice` and
-      :py:meth:`~imas.db_entry.DBEntry.get_sample` (with IMAS-Core>=5.4).
-    - If you can't have access to it, you can save IDS to disk with the built-in
-      netCDF backend :ref:`Load and store an IDS to disk with netCDF`
-
 To store an IDS to disk, we need to indicate the following URI to the
 IMAS-Core: ``imas:<backend>?path=<path_to_folder>`` or using the legacy query keys
 ``imas:<backend>?user=<user>;database=<database>;version=<version>;pulse=<pulse>;run=<run>``
@@ -115,11 +104,9 @@ In IMAS-Python you do this as follows:
     >>> # now store the core_profiles IDS we just populated
     >>> dbentry.put(core_profiles)
 
-.. image:: imas_structure.png
-
 To load an IDS from disk, you need to specify the same information as
 when storing the IDS (see above). Once the data entry is opened, you
-can use ``<IDS>.get()`` to load IDS data from disk: 
+can use ``dbentry.get()`` to load IDS data from disk: 
 
 .. code-block:: python
 
@@ -146,11 +133,34 @@ In IMAS-Python you do this as follows:
 
 To load an IDS from disk, you need to specify the same file information as
 when storing the IDS. Once the data entry is opened, you
-can use ``<IDS>.get()`` to load IDS data from disk: 
+can use ``dbentry.get()`` to load IDS data from disk: 
 
 .. code-block:: python
 
     >>> # Now load the core_profiles IDS back from disk
     >>> dbentry2 = imas.DBEntry("mypulsefile.nc","r")
     >>> core_profiles2 = dbentry2.get("core_profiles")
     >>> print(core_profiles2.ids_properties.comment.value)
+
+
+Data Entry API overview
+'''''''''''''''''''''''
+
+See the documentation of :py:class:`imas.DBEntry <imas.db_entry.DBEntry>` for more
+details on reading and writing IDSs to disk. Useful functions include:
+
+- :py:meth:`~imas.db_entry.DBEntry.put` and :py:meth:`~imas.db_entry.DBEntry.put_slice`
+  to write a full IDS or write append a time slice to existing data.
+- :py:meth:`~imas.db_entry.DBEntry.get`, :py:meth:`~imas.db_entry.DBEntry.get_slice` and
+  :py:meth:`~imas.db_entry.DBEntry.get_sample` to read all time slices, a single time
+  slice, or a sample of time slices from disk. ``get_slice()`` and ``get_sample()`` can
+  also interpolate data to a requested point in time.
+
+  All three ``get()`` methods have a ``lazy`` mode, which will only load data from disk
+  when you need it. This can greatly speed up data access in some scenarios. See
+  :ref:`Lazy loading` for more details.
+- :py:meth:`~imas.db_entry.DBEntry.list_all_occurrences` to query whether there are any
+  occurrences of a certain IDS stored on disk.
+- :py:meth:`~imas.db_entry.DBEntry.list_filled_paths` to query which Data Dictionary
+  paths have data filled inside a specific IDS.
+

imas/backends/db_entry_impl.py

@@ -120,3 +120,11 @@ def delete_data(self, ids_name: str, occurrence: int) -> None:
     @abstractmethod
     def list_all_occurrences(self, ids_name: str) -> List[int]:
         """Implement DBEntry.list_all_occurrences()"""
+
+    @abstractmethod
+    def list_filled_paths(self, ids_name: str, occurrence: int) -> List[str]:
+        """Implement DBEntry.list_filled_paths().
+
+        N.B. DD conversion is handled in DBEntry.list_filled_paths(), this method
+        returns the data paths as stored on-disk.
+        """

imas/backends/imas_core/al_context.py

@@ -174,6 +174,17 @@ def list_all_occurrences(self, ids_name: str) -> List[int]:
             return list(occurrences)
         return []
 
+    def list_filled_paths(self, path: str) -> List[str]:
+        """List all filled paths in an IDS.
+
+        Args:
+            path: IDS and occurrence as a string: <IDS>[/<occurrence>]
+        """
+        status, result = ll_interface.list_filled_paths(self.ctx, path)
+        if status != 0:
+            raise LowlevelError(f"list filled paths for {path!r}", status)
+        return result
+
     def close(self):
         """Close this ALContext."""
         ll_interface.end_action(self.ctx)

imas/backends/imas_core/db_entry_al.py

@@ -364,6 +364,19 @@ def list_all_occurrences(self, ids_name: str) -> List[int]:
             ) from None
         return occurrence_list
 
+    def list_filled_paths(self, ids_name: str, occurrence: int) -> List[str]:
+        if self._db_ctx is None:
+            raise RuntimeError("Database entry is not open.")
+        ll_path = ids_name
+        if occurrence != 0:
+            ll_path += f"/{occurrence}"
+        paths = self._db_ctx.list_filled_paths(ll_path)
+        if not paths:
+            raise DataEntryException(
+                f"IDS {ids_name!r}, occurrence {occurrence} is empty."
+            )
+        return paths
+
     def _check_uda_warnings(self, lazy: bool) -> None:
         """Various checks / warnings for the UDA backend."""
         cache_mode = self._querydict.get("cache_mode")

imas/backends/imas_core/imas_interface.py

@@ -166,6 +166,11 @@ def begin_timerange_action(
     ):
         raise self._minimal_version("5.4")
 
+    # New method in AL 5.7
+
+    def list_filled_paths(self, ctx, path):
+        raise self._minimal_version("5.7")
+
 
 # Dummy documentation for interface:
 for funcname in dir(LowlevelInterface):

imas/backends/netcdf/db_entry_nc.py

@@ -92,6 +92,14 @@ def close(self, *, erase: bool = False) -> None:
             )
         self._dataset.close()
 
+    def _get_group(self, ids_name: str, occurrence: int) -> "netCDF4.Group":
+        try:
+            return self._dataset[f"{ids_name}/{occurrence}"]
+        except LookupError as exc:
+            raise DataEntryException(
+                f"IDS {ids_name!r}, occurrence {occurrence} is not found."
+            ) from exc
+
     def get(
         self,
         ids_name: str,
@@ -110,12 +118,7 @@ def get(
             raise NotImplementedError(f"`{func}` is not available for netCDF files.")
 
         # Check if the IDS/occurrence exists, and obtain the group it is stored in
-        try:
-            group = self._dataset[f"{ids_name}/{occurrence}"]
-        except KeyError:
-            raise DataEntryException(
-                f"IDS {ids_name!r}, occurrence {occurrence} is not found."
-            )
+        group = self._get_group(ids_name, occurrence)
 
         # Load data into the destination IDS
         if self._ds_factory.dd_version == destination._dd_version:
@@ -183,3 +186,17 @@ def list_all_occurrences(self, ids_name: str) -> List[int]:
 
         occurrence_list.sort()
         return occurrence_list
+
+    def list_filled_paths(self, ids_name: str, occurrence: int) -> List[str]:
+        # Check if the IDS/occurrence exists, and obtain the group it is stored in
+        group = self._get_group(ids_name, occurrence)
+
+        result = []
+        for name, variable in group.variables.items():
+            if variable.ndim == 0 and variable.dtype == "S1":
+                continue  # (Array of) Structure metadata node, no data
+            if name.endswith(":shape"):
+                continue  # Shape data, not a DD path
+            result.append(name.replace(".", "/"))
+
+        return result

imas/db_entry.py

@@ -7,7 +7,7 @@
 import logging
 import os
 import pathlib
-from typing import Any, Type, overload
+from typing import Any, Type, overload, List
 
 import numpy
 
@@ -197,14 +197,14 @@ def _select_implementation(uri: str | None) -> Type[DBEntryImpl]:
             from imas.backends.imas_core.db_entry_al import ALDBEntryImpl as impl
         return impl
 
-    def __enter__(self):
+    def __enter__(self) -> "DBEntry":
         # Context manager protocol
         if self._dbe_impl is None:
             # Open if the DBEntry was not already opened or created
             self.open()
         return self
 
-    def __exit__(self, exc_type, exc_value, traceback):
+    def __exit__(self, exc_type, exc_value, traceback) -> None:
         # Context manager protocol
         self.close()
 
@@ -800,3 +800,62 @@ def list_all_occurrences(self, ids_name, node_path=None):
             self.get(ids_name, occ, lazy=True)[node_path] for occ in occurrence_list
         ]
         return occurrence_list, node_content_list
+
+    def list_filled_paths(
+        self, ids_name, occurrence: int = 0, *, autoconvert: bool = True
+    ) -> List[str]:
+        """Get a list of filled Data Dictionary paths from the backend.
+
+        Note that this is only supported by some backends (HDF5 and netCDF), and will
+        result in an error on unsupported backends.
+
+        Args:
+            ids_name: Name of the IDS to request filled data for.
+            occurrence: Occurrence number of the IDS to request filled data for.
+
+        Keyword Args:
+            autoconvert: If enabled (default), this method will take NBC renames into
+                account in the returned list of filled paths.
+
+        Returns:
+            List of paths which have some data filled in the backend. For example, when
+            ``profiles_1d/ion/temperature`` is in this list, it means that there is at
+            least one ``ion`` in one ``profiles_1d`` entry for which the temperature is
+            filled.
+
+            The paths in this list may be ordered arbitrarily.
+
+        Example:
+            >>> with imas.DBEntry("imas:hdf5?path=./path/to/data", "r") as entry:
+            >>>     print(entry.list_filled_paths("core_profiles"))
+            ['ids_properties/comment', 'ids_properties/homogeneous_time',
+             'profiles_1d/grid/rho_tor_norm', 'profiles_1d/electrons/temperature',
+             'profiles_1d/ion/temperature', 'time']
+        """
+        if self._dbe_impl is None:
+            raise RuntimeError("Database entry is not open.")
+        paths = self._dbe_impl.list_filled_paths(ids_name, occurrence)
+        if not autoconvert:
+            return paths
+
+        # DD conversion?
+        dd_version = self._dbe_impl.read_dd_version(ids_name, occurrence)
+        if dd_version == self._ids_factory.dd_version:
+            return paths  # No conversion required
+
+        # Follow any NBC renames:
+        ddmap, source_is_older = dd_version_map_from_factories(
+            ids_name, IDSFactory(version=dd_version), self._ids_factory
+        )
+        nbc_map = ddmap.old_to_new if source_is_older else ddmap.new_to_old
+
+        converted_paths = []
+        for path in paths:
+            if path in nbc_map:
+                new_name = nbc_map.path[path]
+                if new_name is not None:
+                    converted_paths.append(new_name)
+            else:
+                converted_paths.append(path)
+
+        return converted_paths

imas/test/test_list_filled_paths.py

@@ -0,0 +1,101 @@
+import pytest
+
+import imas
+from imas_core import _al_lowlevel
+from imas.exception import DataEntryException
+from imas.ids_defs import IDS_TIME_MODE_HOMOGENEOUS, IDS_TIME_MODE_INDEPENDENT
+
+
+if not hasattr(_al_lowlevel, "al_list_filled_paths"):
+    marker = pytest.mark.xfail(reason="list_filled_paths not available in imas_core")
+else:
+    marker = []
+
+
+@pytest.fixture(params=["netcdf", pytest.param("hdf5", marks=marker)])
+def testuri(request, tmp_path):
+    if request.param == "netcdf":
+        return str(tmp_path / "list_filled_paths.nc")
+    return f"imas:{request.param}?path={tmp_path}/list_filled_paths_{request.param}"
+
+
+def test_list_filled_paths(testuri):
+    with imas.DBEntry(testuri, "w", dd_version="4.0.0") as dbentry:
+        # No IDSs in the DBEntry yet, expect an exception
+        with pytest.raises(DataEntryException):
+            dbentry.list_filled_paths("core_profiles")
+
+        cp = dbentry.factory.core_profiles()
+        cp.ids_properties.homogeneous_time = IDS_TIME_MODE_HOMOGENEOUS
+        cp.ids_properties.comment = "comment"
+        cp.time = [0.1, 0.2]
+        cp.profiles_1d.resize(2)
+        cp.profiles_1d[0].grid.rho_tor_norm = [1.0, 2.0]
+        cp.profiles_1d[0].ion.resize(2)
+        cp.profiles_1d[0].ion[1].temperature = [1.0, 2.0]
+        cp.profiles_1d[1].grid.psi = [1.0, 2.0]
+        cp.profiles_1d[1].q = [1.0, 2.0]
+        cp.profiles_1d[1].e_field.radial = [1.0, 2.0]
+        cp.profiles_1d[1].neutral.resize(2)
+        cp.global_quantities.ip = [1.0, 2.0]
+
+        dbentry.put(cp)
+
+        filled_paths = dbentry.list_filled_paths("core_profiles")
+        assert isinstance(filled_paths, list)
+        assert set(filled_paths) == {
+            "ids_properties/version_put/access_layer",
+            "ids_properties/version_put/access_layer_language",
+            "ids_properties/version_put/data_dictionary",
+            "ids_properties/homogeneous_time",
+            "ids_properties/comment",
+            "time",
+            "profiles_1d/grid/rho_tor_norm",
+            "profiles_1d/ion/temperature",
+            "profiles_1d/grid/psi",
+            "profiles_1d/q",
+            "profiles_1d/e_field/radial",
+            "profiles_1d/e_field/radial",
+            "global_quantities/ip",
+        }
+        # Other occurrence should still raise an error:
+        with pytest.raises(DataEntryException):
+            dbentry.list_filled_paths("core_profiles", 1)
+        # Until we write data to the occurrence:
+        dbentry.put(cp, 3)
+        assert set(filled_paths) == set(dbentry.list_filled_paths("core_profiles", 3))
+
+
+def test_list_filled_paths_autoconvert(testuri):
+    with imas.DBEntry(testuri, "w", dd_version="3.25.0") as entry:
+        ps = entry.factory.pulse_schedule()
+        ps.ids_properties.homogeneous_time = IDS_TIME_MODE_INDEPENDENT
+        ps.ec.antenna.resize(1)
+        ps.ec.antenna[0].launching_angle_pol.reference_name = "test"
+        entry.put(ps)
+
+        filled_paths = entry.list_filled_paths("pulse_schedule")
+        assert set(filled_paths) == {
+            "ids_properties/version_put/access_layer",
+            "ids_properties/version_put/access_layer_language",
+            "ids_properties/version_put/data_dictionary",
+            "ids_properties/homogeneous_time",
+            "ec/antenna/launching_angle_pol/reference_name",
+        }
+
+    # Check autoconvert with DD 3.28.0
+    with imas.DBEntry(testuri, "r", dd_version="3.28.0") as entry:
+        assert set(entry.list_filled_paths("pulse_schedule", autoconvert=False)) == {
+            "ids_properties/version_put/access_layer",
+            "ids_properties/version_put/access_layer_language",
+            "ids_properties/version_put/data_dictionary",
+            "ids_properties/homogeneous_time",
+            "ec/antenna/launching_angle_pol/reference_name",  # original name
+        }
+        assert set(entry.list_filled_paths("pulse_schedule")) == {
+            "ids_properties/version_put/access_layer",
+            "ids_properties/version_put/access_layer_language",
+            "ids_properties/version_put/data_dictionary",
+            "ids_properties/homogeneous_time",
+            "ec/launcher/steering_angle_pol/reference_name",  # autoconverted name
+        }