grib2 tests

.github/workflows/tests.yml

@@ -23,4 +23,5 @@ jobs:
       - name: Test with pytest
         shell: bash -l {0}
         run: |
+          export ZARR_V3_EXPERIMENTAL_API=1
           pytest -v --cov

kerchunk/grib2.py

@@ -24,7 +24,7 @@
 import xarray
 import numpy as np
 
-from kerchunk.utils import class_factory, _encode_for_JSON
+from kerchunk.utils import class_factory, _encode_for_JSON, zarr_init_group_and_store
 from kerchunk.codecs import GRIBCodec
 from kerchunk.combine import MultiZarrToZarr, drop
 
@@ -113,6 +113,7 @@ def scan_grib(
     inline_threshold=100,
     skip=0,
     filter={},
+    zarr_version=None,
 ):
     """
     Generate references for a GRIB2 file
@@ -134,6 +135,9 @@ def scan_grib(
         the exact value or is in the given set, are processed.
         E.g., the cf-style filter ``{'typeOfLevel': 'heightAboveGround', 'level': 2}``
         only keeps messages where heightAboveGround==2.
+    zarr_version: int
+        The desired zarr spec version to target (currently 2 or 3). The default
+        of None will use the default zarr version.
 
     Returns
     -------
@@ -192,7 +196,7 @@ def scan_grib(
             if good is False:
                 continue
 
-            z = zarr.open_group(store)
+            z, store = zarr_init_group_and_store(store, zarr_version=zarr_version)
             global_attrs = {
                 f"GRIB_{k}": m[k]
                 for k in cfgrib.dataset.GLOBAL_ATTRIBUTES_KEYS

kerchunk/tests/test_grib.py

@@ -21,14 +21,19 @@
 here = os.path.dirname(__file__)
 
 
-def test_one():
+@pytest.mark.parametrize("zarr_version", [2, 3])
+def test_one(zarr_version):
     # from https://dd.weather.gc.ca/model_gem_regional/10km/grib2/00/000
     fn = os.path.join(here, "CMC_reg_DEPR_ISBL_10_ps10km_2022072000_P000.grib2")
-    out = scan_grib(fn)
+    out = scan_grib(fn, zarr_version=zarr_version)
     ds = xr.open_dataset(
         "reference://",
         engine="zarr",
-        backend_kwargs={"consolidated": False, "storage_options": {"fo": out[0]}},
+        backend_kwargs={
+            "consolidated": False,
+            "zarr_version": zarr_version,
+            "storage_options": {"fo": out[0]},
+        },
     )
 
     assert ds.attrs["GRIB_centre"] == "cwao"