Open json files as ModelLibrary if romancal is installed

.github/workflows/ci.yml

@@ -33,3 +33,9 @@ jobs:
     with:
       envs: |
         - linux: rad
+  test_with_romancal:
+    uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@v1
+    with:
+      envs: |
+        - linux: withromancal
+          coverage: codecov

changes/389.feature.rst

@@ -0,0 +1 @@
+Open ``.json`` files as ``ModelLibrary`` if ``romancal`` is installed.

src/roman_datamodels/datamodels/_utils.py

@@ -63,6 +63,14 @@ def rdm_open(init, memmap=False, **kwargs):
     -------
     `DataModel`
     """
+    if isinstance(init, str | Path):
+        if Path(init).suffix.lower() == ".json":
+            try:
+                from romancal.datamodels.library import ModelLibrary
+
+                return ModelLibrary(init)
+            except ImportError:
+                raise ImportError("Please install romancal to allow opening associations with roman_datamodels")
     with validate.nuke_validation():
         if isinstance(init, DataModel):
             # Copy the object so it knows not to close here
@@ -76,14 +84,5 @@ def rdm_open(init, memmap=False, **kwargs):
         if (model_type := type(asdf_file.tree["roman"])) in MODEL_REGISTRY:
             return MODEL_REGISTRY[model_type](asdf_file, **kwargs)
 
-        if isinstance(init, str):
-            exts = Path(init).suffixes
-            if not exts:
-                raise ValueError(f"Input file path does not have an extension: {init}")
-
-            # Assume json files are asn and return them
-            if exts[0] == "json":
-                return init
-
         asdf_file.close()
         raise TypeError(f"Unknown datamodel type: {model_type}")

tests/test_open.py

@@ -1,3 +1,4 @@
+import json
 from pathlib import Path
 
 import asdf
@@ -236,3 +237,23 @@ def test_rdm_open_non_datamodel():
 
     with pytest.raises(TypeError, match=r"Unknown datamodel type: .*"):
         rdm_open(Path(__file__).parent / "data" / "not_a_datamodel.asdf")
+
+
+def test_open_asn(tmp_path):
+    romancal = pytest.importorskip("romancal")
+
+    fn = tmp_path / "test.json"
+    asn = {
+        "products": [
+            {
+                "members": [],
+                "name": "foo",
+            }
+        ],
+    }
+    with open(fn, "w") as f:
+        json.dump(asn, f)
+
+    lib = datamodels.open(fn)
+
+    assert isinstance(lib, romancal.datamodels.ModelLibrary)

tox.ini

@@ -4,6 +4,7 @@ env_list =
     test{,-devdeps}{,-pyargs,-cov}-xdist
     test-numpy{120,121,122}-xdist
     build-{docs,dist}
+    withromancal
 
 # tox environments are constructed with so-called 'factors' (or terms)
 # separated by hyphens, e.g. test-devdeps-cov. Lines below starting with factor:
@@ -69,3 +70,19 @@ deps =
     build
 commands =
     python -m build .
+
+[testenv:withromancal]
+allowlist_externals =
+    git
+    bash
+deps =
+    pytest-cov
+commands_pre =
+    bash -c "pip freeze -q | grep 'roman_datamodels @' > {env_tmp_dir}/requirements.txt"
+    pip install git+https://github.com/spacetelescope/romancal.git
+    pip install -r {env_tmp_dir}/requirements.txt
+    pip freeze
+commands =
+    pytest tests/test_open.py::test_open_asn \
+    --cov=tests --cov-config pyproject.toml --cov-report term-missing --cov-report xml \
+    {posargs}