Set default ZarrPlugin prefix to /zarr (#188)

* Set default ZarrPlugin prefix to /zarr

Closes #182

* Sort Zarr coordinates

* Add error message for zmetadata test when coordinates are swapped

* xfail on existing zmetadata test, and add a new test that sorts xarray zmeta

tests/test_rest_api.py

@@ -288,42 +288,42 @@ def test_repr(airtemp_ds, airtemp_app_client):
 
 
 def test_zmetadata(airtemp_ds, airtemp_app_client):
-    response = airtemp_app_client.get('/.zmetadata')
+    response = airtemp_app_client.get('/zarr/.zmetadata')
     assert response.status_code == 200
     assert json.dumps(response.json()) == json.dumps(
         jsonify_zmetadata(airtemp_ds, create_zmetadata(airtemp_ds))
     )
 
 
 def test_bad_key(airtemp_app_client):
-    response = airtemp_app_client.get('/notakey')
+    response = airtemp_app_client.get('/zarr/notakey')
     assert response.status_code == 404
 
 
 def test_zgroup(airtemp_app_client):
-    response = airtemp_app_client.get('/.zgroup')
+    response = airtemp_app_client.get('/zarr/.zgroup')
     assert response.status_code == 200
 
 
 def test_zarray(airtemp_app_client):
-    response = airtemp_app_client.get('/air/.zarray')
+    response = airtemp_app_client.get('/zarr/air/.zarray')
     assert response.status_code == 200
 
 
 def test_zattrs(airtemp_app_client):
-    response = airtemp_app_client.get('/air/.zattrs')
+    response = airtemp_app_client.get('/zarr/air/.zattrs')
     assert response.status_code == 200
-    response = airtemp_app_client.get('/.zattrs')
+    response = airtemp_app_client.get('/zarr/.zattrs')
     assert response.status_code == 200
 
 
 def test_get_chunk(airtemp_app_client):
-    response = airtemp_app_client.get('/air/0.0.0')
+    response = airtemp_app_client.get('/zarr/air/0.0.0')
     assert response.status_code == 200
 
 
 def test_array_group_raises_404(airtemp_app_client):
-    response = airtemp_app_client.get('/air/.zgroup')
+    response = airtemp_app_client.get('/zarr/air/.zgroup')
     assert response.status_code == 404
 
 
@@ -333,12 +333,12 @@ def test_cache(airtemp_ds):
 
     client = TestClient(rest.app)
 
-    response1 = client.get('/air/0.0.0')
+    response1 = client.get('/zarr/air/0.0.0')
     assert response1.status_code == 200
     assert '/air/0.0.0' in rest.cache
 
     # test that we can retrieve
-    response2 = client.get('/air/0.0.0')
+    response2 = client.get('/zarr/air/0.0.0')
     assert response2.status_code == 200
     assert response1.content == response2.content
 
@@ -377,7 +377,7 @@ def test_ds_dict_keys(ds_dict, ds_dict_app_client):
     assert response.status_code == 200
     assert response.json() == list(ds_dict)
 
-    response = ds_dict_app_client.get('/datasets/not_in_dict')
+    response = ds_dict_app_client.get('/datasets/zarr/not_in_dict')
     assert response.status_code == 404
 
 
@@ -386,7 +386,7 @@ def test_ds_dict_cache(ds_dict):
 
     client = TestClient(rest.app)
 
-    response1 = client.get('/datasets/ds1/var/0')
+    response1 = client.get('/datasets/ds1/zarr/var/0')
     assert response1.status_code == 200
     assert 'ds1/var/0' in rest.cache
 

tests/test_zarr_compat.py

@@ -41,7 +41,19 @@ def test_zmetadata_identical(start, end, freq, nlats, nlons, var_const, calendar
 @pytest.mark.parametrize(
     'start, end, freq, nlats, nlons, var_const, calendar, use_cftime',
     [
-        ('2018-01-01', '2021-01-01', 'MS', 15, 30, True, 'standard', False),
+        pytest.param(
+            '2018-01-01',
+            '2021-01-01',
+            'MS',
+            15,
+            30,
+            True,
+            'standard',
+            False,
+            marks=pytest.mark.xfail(
+                reason="Xarray's ordering of metadata coords in a string can very"
+            ),
+        ),
     ],
 )
 def test_zmetadata_identical_coords(
@@ -65,6 +77,53 @@ def test_zmetadata_identical_coords(
     mapper = TestMapper(SingleDatasetRest(ds).app)
     actual = json.loads(mapper['.zmetadata'].decode())
     expected = json.loads(zarr_dict['.zmetadata'].decode())
+    assert (
+        actual == expected
+    ), "Zarr metadata did not match, likely because array coordinates aren't sorted by Xarray"
+
+
+@pytest.mark.parametrize(
+    'start, end, freq, nlats, nlons, var_const, calendar, use_cftime',
+    [
+        (
+            '2018-01-01',
+            '2021-01-01',
+            'MS',
+            15,
+            30,
+            True,
+            'standard',
+            False,
+        ),
+    ],
+)
+def test_zmetadata_identical_coords_sorted(
+    start, end, freq, nlats, nlons, var_const, calendar, use_cftime
+):
+    """Test that zmetadata passes when coords are explicitly sorted"""
+    ds = create_dataset(
+        start=start,
+        end=end,
+        freq=freq,
+        nlats=nlats,
+        nlons=nlons,
+        var_const=var_const,
+        use_cftime=use_cftime,
+        calendar=calendar,
+        use_xy_dim=True,
+    )
+
+    ds = ds.chunk(ds.dims)
+    zarr_dict = {}
+    ds.to_zarr(zarr_dict, consolidated=True)
+    mapper = TestMapper(SingleDatasetRest(ds).app)
+    actual = json.loads(mapper['.zmetadata'].decode())
+    expected = json.loads(zarr_dict['.zmetadata'].decode())
+
+    for key in ['tmin/.zattrs', 'tmax/.zattrs']:
+        coords = expected['metadata'][key]['coordinates']
+        expected['metadata'][key]['coordinates'] = ' '.join(sorted(coords.split(' ')))
+
     assert actual == expected
 
 

tests/utils.py

@@ -16,9 +16,10 @@ class TestMapper(TestClient, BaseStore):
     """
 
     def __getitem__(self, key):
-        response = self.get(key)
+        zarr_key = f'/zarr/{key}'
+        response = self.get(zarr_key)
         if response.status_code != 200:
-            raise KeyError('{} not found. status_code = {}'.format(key, response.status_code))
+            raise KeyError('{} not found. status_code = {}'.format(zarr_key, response.status_code))
         return response.content
 
     def __delitem__(self, key):

xpublish/plugins/included/zarr.py

@@ -23,7 +23,7 @@ class ZarrPlugin(Plugin):
 
     name = 'zarr'
 
-    dataset_router_prefix: str = ''
+    dataset_router_prefix: str = '/zarr'
     dataset_router_tags: Sequence[str] = ['zarr']
 
     @hookimpl

xpublish/utils/zarr.py

@@ -58,7 +58,7 @@ def _extract_dataarray_coords(da, zattrs):
         nondim_coords = set(da.coords) - set(da.dims)
 
         if len(nondim_coords) > 0 and da.name not in nondim_coords:
-            coords = ' '.join(list(nondim_coords))
+            coords = ' '.join(sorted(list(nondim_coords)))
             zattrs['coordinates'] = encode_zarr_attr_value(coords)
     return zattrs