no longer require SliceSOurce instances, renamed slice_obj -> slice_item

Author: forman

tests/test_slice.py

@@ -1,6 +1,7 @@
 # Copyright © 2024 Norman Fomferra
 # Permissions are hereby granted under the terms of the MIT License:
 # https://opensource.org/licenses/MIT.
+
 import shutil
 import unittest
 import warnings
@@ -60,18 +61,18 @@ def test_slice_source_class_slice_source_fails(self):
         with pytest.raises(
             TypeError,
             match=(
-                "expected an instance of SliceSource returned from"
-                " 'false_slice_source_function', but got <class 'int'>"
+                "slice_item must be a str, zappend.fsutil.FileObj,"
+                " zappend.slice.SliceSource, xarray.Dataset, or a callable"
             ),
         ):
             open_slice_source(ctx, "test.nc")
 
     def test_slice_source_slice_source(self):
         dataset = make_test_dataset()
         ctx = Context(dict(target_dir="memory://target.zarr"))
-        slice_obj = MemorySliceSource(ctx, dataset, 0)
-        slice_source = open_slice_source(ctx, slice_obj)
-        self.assertIs(slice_obj, slice_source)
+        slice_item = MemorySliceSource(ctx, dataset, 0)
+        slice_source = open_slice_source(ctx, slice_item)
+        self.assertIs(slice_item, slice_source)
 
     def test_slice_factory_slice_source(self):
         dataset = make_test_dataset()
@@ -189,7 +190,7 @@ def test_it_raises_on_persistent_wait_fail(self):
     # noinspection PyMethodMayBeStatic
     def test_it_raises_on_invalid_type(self):
         ctx = Context(dict(target_dir="memory://target.zarr"))
-        with pytest.raises(TypeError, match="slice_obj must be a str, "):
+        with pytest.raises(TypeError, match="slice_item must be a str, "):
             # noinspection PyTypeChecker
             open_slice_source(ctx, 42)
 

zappend/slice/factory.py

@@ -26,10 +26,10 @@
 
 def open_slice_source(
     ctx: Context,
-    slice_obj: SliceObj | SliceFactory | Any,
+    slice_item: SliceObj | SliceFactory | Any,
     slice_index: int = 0,
 ) -> SliceSource:
-    """Open the slice source for given slice object `slice_obj`.
+    """Open the slice source for given slice object `slice_item`.
 
     The intended and only use of the returned slice source is as context
     manager. When used as context manager the slice source yields a slice
@@ -39,7 +39,7 @@ def open_slice_source(
     class derived from `zappend.slice.SliceSource` or a function that returns
     instances of `zappend.slice.SliceSource`. The retrieved slice source will
     be returned by this function. The class or function will receive positional
-    and keyword arguments derived from `slice_obj` as follows:
+    and keyword arguments derived from `slice_item` as follows:
 
     * `tuple`: a pair of the form `(args, kwargs)`, where `args` is a list
       or tuple of positional arguments and `kwargs` is a dictionary of keyword
@@ -49,7 +49,7 @@ class derived from `zappend.slice.SliceSource` or a function that returns
     * Any other type is interpreted as single positional argument.
 
     If `slice_source` is not specified in the configuration, the slice object
-    `slice_obj` may have one of the following types:
+    `slice_item` may have one of the following types:
 
     * `str`: A local file path or URI pointing to a dataset file such as a
       Zarr or NetCDF. If it is a URI, the `ctx.slice_storage_options` apply.
@@ -63,54 +63,46 @@ class derived from `zappend.slice.SliceSource` or a function that returns
 
     Args:
         ctx: The processing context
-        slice_obj: A slice object
+        slice_item: An slice item
         slice_index: Optional slice index, used for dataset identification
 
     Returns:
         A new slice source instance
     """
     _slice_source = ctx.config.slice_source
     if _slice_source is not None:
-        slice_args, slice_kwargs = normalize_slice_arg(slice_obj)
-        slice_factory = to_slice_factory(_slice_source, *slice_args, **slice_kwargs)
-        slice_source = slice_factory(ctx)
-        if not isinstance(slice_source, SliceSource):
-            raise TypeError(
-                f"expected an instance of SliceSource"
-                f" returned from {_slice_source.__name__!r},"
-                f" but got {type(slice_source)}"
-            )
-        return slice_source
+        slice_args, slice_kwargs = normalize_slice_arg(slice_item)
+        slice_item = to_slice_factory(_slice_source, *slice_args, **slice_kwargs)
 
-    return _get_slice_dataset_recursively(ctx, slice_obj, slice_index)
+    return _get_slice_dataset_recursively(ctx, slice_item, slice_index)
 
 
 def _get_slice_dataset_recursively(
     ctx: Context,
-    slice_obj: SliceObj | SliceFactory,
+    slice_item: SliceObj | SliceFactory,
     slice_index: int,
 ) -> SliceSource:
-    if isinstance(slice_obj, SliceSource):
-        return slice_obj
-    if isinstance(slice_obj, (str, FileObj)):
-        if isinstance(slice_obj, str):
+    if isinstance(slice_item, SliceSource):
+        return slice_item
+    if isinstance(slice_item, (str, FileObj)):
+        if isinstance(slice_item, str):
             slice_file = FileObj(
-                slice_obj, storage_options=ctx.config.slice_storage_options
+                slice_item, storage_options=ctx.config.slice_storage_options
             )
         else:
-            slice_file = slice_obj
+            slice_file = slice_item
         return PersistentSliceSource(ctx, slice_file)
-    if isinstance(slice_obj, xr.Dataset):
+    if isinstance(slice_item, xr.Dataset):
         if ctx.config.persist_mem_slices:
-            return TemporarySliceSource(ctx, slice_obj, slice_index)
+            return TemporarySliceSource(ctx, slice_item, slice_index)
         else:
-            return MemorySliceSource(ctx, slice_obj, slice_index)
-    if callable(slice_obj):
-        slice_factory: SliceFactory = slice_obj
-        slice_obj = slice_factory(ctx)
-        return _get_slice_dataset_recursively(ctx, slice_obj, slice_index)
+            return MemorySliceSource(ctx, slice_item, slice_index)
+    if callable(slice_item):
+        slice_factory: SliceFactory = slice_item
+        slice_item = slice_factory(ctx)
+        return _get_slice_dataset_recursively(ctx, slice_item, slice_index)
     raise TypeError(
-        "slice_obj must be a"
+        "slice_item must be a"
         " str,"
         " zappend.fsutil.FileObj,"
         " zappend.slice.SliceSource,"