Predicates for is-SOMA and is-SOMA-collection

apis/python/src/tiledbsc/tiledb_array.py

@@ -113,7 +113,7 @@ def _set_soma_object_type_metadata(self) -> None:
         """
         with self._open("w") as A:
             A.meta[
-                tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY
+                tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY
             ] = self.__class__.__name__
 
     def show_metadata(self, recursively=True, indent=""):

apis/python/src/tiledbsc/tiledb_group.py

@@ -79,7 +79,7 @@ def _set_soma_object_type_metadata(self):
         """
         with self._open("w") as G:
             G.meta[
-                tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY
+                tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY
             ] = self.__class__.__name__
 
     def _set_soma_object_type_metadata_recursively(self):

apis/python/src/tiledbsc/util.py

@@ -9,10 +9,84 @@
 import time
 from typing import Optional, List, Union
 
+# This is for group/array metadata we write, to help nested-structured traversals (especially those
+# that start at the SOMACollection level) confidently navigate with a minimum of introspection on
+# group contents.
+SOMA_OBJECT_TYPE_METADATA_KEY = "soma_object_type"
+
 # ----------------------------------------------------------------
-def is_local_path(path: str) -> bool:
+def is_soma(uri: str, ctx: Optional[tiledb.Ctx] = None) -> bool:
+    """
+    Tells whether the URI points to a SOMA or not.
     """
+    # A SOMA is a TileDB group, but TileDB uses groups for many things including SOMACollections and
+    # SOMA elements such as obs and var. If this is not a group, we say it is not a SOMA; if it is,
+    # we ask more questions.
+    if tiledb.object_type(uri, ctx=ctx) != "group":
+        return False
+
+    # We can check object-type metadata, but it's possible the URI was created using an
+    # early-access/beta-level version of our code that wasn't yet writing object-type metadata.  If
+    # we find object-type metadata saying this TileDB group is a SOMA, we say so; if not, we ask
+    # more questions.
+    with tiledb.Group(uri, mode="r", ctx=ctx) as G:
+        if SOMA_OBJECT_TYPE_METADATA_KEY in G.meta:
+            # Really `tiledbsc.SOMA.__name__`, but prevent a circular package import, so `"SOMA"`
+            return G.meta[SOMA_OBJECT_TYPE_METADATA_KEY] == "SOMA"
+
+        # At this point this path could be a SOMACollection, SOMA, or maybe SOMA element
+        # (or some manually created TileDB group).
+        if "obs" in G and "var" in G:
+            return True
+
+    # There is a chance that:
+    # o this is a TileDB group;
+    # o it's intended to hold a SOMA but it hasn't been populated yet;
+    # o it was created before object-type metadata was put in place;
+    # o it's remained unpopulated this whole time.
+    # Here we say this is not a SOMA, and accept the small risk of false negative.
+    return False
 
+
+# ----------------------------------------------------------------
+def is_soma_collection(uri: str, ctx: Optional[tiledb.Ctx] = None) -> bool:
+    """
+    Tells whether the URI points to a SOMACollection or not.
+    """
+    # A SOMACollection is a TileDB group, but TileDB uses groups for many things including SOMAs and
+    # SOMA elements such as obs and var. If this is not a group, we say it is not a SOMACollection;
+    # if it is, we ask more questions.
+    if tiledb.object_type(uri, ctx=ctx) != "group":
+        return False
+
+    # We can check object-type metadata, but it's possible the URI was created using an
+    # early-access/beta-level version of our code that wasn't yet writing object-type metadata.  If
+    # we find object-type metadata saying this TileDB group is a SOMA, we say so; if not, we ask
+    # more questions.
+    with tiledb.Group(uri, mode="r", ctx=ctx) as G:
+        if SOMA_OBJECT_TYPE_METADATA_KEY in G.meta:
+            # Really `tiledbsc.SOMA.__name__`, but prevent a circular package import, so `"SOMA"`
+            return G.meta[SOMA_OBJECT_TYPE_METADATA_KEY] == "SOMACollection"
+
+        # At this point this path could be a SOMACollection, SOMA, or maybe SOMA element
+        # (or some manually created TileDB group).
+        if "obs" in G and "var" in G:
+            # Very slight chance of false negative if someone created and populated a SOMACollection
+            # using beta-level code, and added a SOMA named 'obs' and another SOMA named 'var'.
+            return False
+
+    # There is a chance that:
+    # o this is a TileDB group;
+    # o it's intended to hold a SOMACollection but it hasn't been populated yet;
+    # o it was created before object-type metadata was put in place;
+    # o it's remained unpopulated this whole time.
+    # Here we say this is a SOMACollection, and accept the small risk of false positive.
+    return True
+
+
+# ----------------------------------------------------------------
+def is_local_path(path: str) -> bool:
+    """
     Returns information about start time of an event. Nominally float seconds since the epoch,
     but articulated here as being compatible with the format_elapsed function.
     """

apis/python/src/tiledbsc/util_tiledb.py

@@ -4,11 +4,6 @@
 import tiledb
 from typing import Optional
 
-# This is for group/array metadata we write, to help nested-structured traversals (especially those
-# that start at the SOMACollection level) confidently navigate with a minimum of introspection on
-# group contents.
-SOMA_OBJECT_TYPE_METADATA_KEY = "soma_object_type"
-
 # ================================================================
 def show_single_cell_group(soma_uri: str, ctx: Optional[tiledb.Ctx] = None):
     """

apis/python/tests/test_basic_anndata_io.py

@@ -52,17 +52,15 @@ def test_import_anndata(adata):
     #   raw/varm/PCs
 
     with tiledb.Group(output_path) as G:
-        assert G.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY] == "SOMA"
+        assert G.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY] == "SOMA"
 
     # Check X/data (dense)
     with tiledb.open(os.path.join(output_path, "X", "data")) as A:
         df = A[:]
         keys = list(df.keys())
         assert keys == ["value", "obs_id", "var_id"]
         assert A.ndim == 2
-        assert (
-            A.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY] == "AssayMatrix"
-        )
+        assert A.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY] == "AssayMatrix"
     # Convenience accessors
     assert soma.X["data"].shape() == soma.X.data.shape()
 
@@ -72,17 +70,14 @@ def test_import_anndata(adata):
         assert df.columns.to_list() == ["obs_id", "var_id", "value"]
         # verify sparsity of raw data
         assert df.shape[0] == orig.raw.X.nnz
-        assert (
-            A.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY] == "AssayMatrix"
-        )
+        assert A.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY] == "AssayMatrix"
 
     # Check obs
     with tiledb.open(os.path.join(output_path, "obs")) as A:
         df = A.df[:]
         assert df.columns.to_list() == orig.obs_keys()
         assert (
-            A.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY]
-            == "AnnotationDataFrame"
+            A.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY] == "AnnotationDataFrame"
         )
     assert sorted(soma.obs.ids()) == sorted(list(orig.obs_names))
     # Convenience accessors
@@ -95,8 +90,7 @@ def test_import_anndata(adata):
         df = A.df[:]
         assert df.columns.to_list() == orig.var_keys()
         assert (
-            A.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY]
-            == "AnnotationDataFrame"
+            A.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY] == "AnnotationDataFrame"
         )
     assert sorted(soma.var.ids()) == sorted(list(orig.var_names))
     # Convenience accessors
@@ -113,7 +107,7 @@ def test_import_anndata(adata):
             assert df.shape[0] == orig.obsm[key].shape[0]
             assert soma.obsm[key].shape() == orig.obsm[key].shape
             assert (
-                A.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY]
+                A.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY]
                 == "AnnotationMatrix"
             )
     # Convenience accessors: soma.obsm.X_pca <-> soma.obsm['X_pca']
@@ -127,7 +121,7 @@ def test_import_anndata(adata):
             assert df.shape[0] == orig.varm[key].shape[0]
             assert soma.varm[key].shape() == orig.varm[key].shape
             assert (
-                A.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY]
+                A.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY]
                 == "AnnotationMatrix"
             )
     # Convenience accessors:
@@ -147,10 +141,7 @@ def test_import_anndata(adata):
             shape = soma.obsp[key].df().shape
             assert shape[0] == orig.obsp[key].nnz
             assert shape[1] == 1
-            assert (
-                A.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY]
-                == "AssayMatrix"
-            )
+            assert A.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY] == "AssayMatrix"
     # Convenience accessors:
     for key in soma.obsp.keys():
         assert getattr(soma.obsp, key).shape() == soma.obsp[key].shape()

apis/python/tests/test_soco_ops.py

@@ -2,6 +2,7 @@
 import tiledb
 import tiledbsc
 import tiledbsc.io
+import tiledbsc.util
 
 import pytest
 import tempfile
@@ -29,7 +30,7 @@ def test_import_anndata(tmp_path):
     soco = tiledbsc.SOMACollection(soco_dir)
 
     with tiledb.Group(soma1_dir) as G:
-        assert G.meta[tiledbsc.util_tiledb.SOMA_OBJECT_TYPE_METADATA_KEY] == "SOMA"
+        assert G.meta[tiledbsc.util.SOMA_OBJECT_TYPE_METADATA_KEY] == "SOMA"
 
     soco.create_unless_exists()
     assert len(soco._get_member_names()) == 0
@@ -43,3 +44,12 @@ def test_import_anndata(tmp_path):
     assert len(soco._get_member_names()) == 1
     soco.remove(soma2)
     assert len(soco._get_member_names()) == 0
+
+    assert tiledbsc.util.is_soma(soma1.uri)
+    assert tiledbsc.util.is_soma(soma2.uri)
+    assert not tiledbsc.util.is_soma(soma1.obs.uri)
+    assert not tiledbsc.util.is_soma(soma2.var.uri)
+
+    assert not tiledbsc.util.is_soma_collection(soma2.var.uri)
+    assert not tiledbsc.util.is_soma_collection(soma2.uri)
+    assert tiledbsc.util.is_soma_collection(soco.uri)