Add JSON parsing and fetching from GitHub (#15)

This is how pre-commit-hooks will get the latest version of the
metadata, since pre-commit caches the environment and doesn't update
rapids-metadata as it's updated.

dependencies.yaml

@@ -67,3 +67,4 @@ dependencies:
       - output_types: [conda, requirements, pyproject]
         packages:
           - pytest
+          - pytest-httpserver

pyproject.toml

@@ -44,6 +44,7 @@ requires = [
 [project.optional-dependencies]
 test = [
     "pytest",
+    "pytest-httpserver",
 ] # This list was generated by `rapids-dependency-file-generator`. To make changes, edit dependencies.yaml and run `rapids-dependency-file-generator`.
 
 [tool.setuptools]

src/rapids_metadata/remote.py

@@ -0,0 +1,33 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import urllib.request
+
+import pydantic
+
+from .metadata import RAPIDSMetadata
+
+
+__all__ = ["fetch_latest"]
+
+_GITHUB_METADATA_URL = "https://raw.githubusercontent.com/rapidsai/rapids-metadata/main/rapids-metadata.json"
+
+
+def _fetch_from_url(url: str) -> RAPIDSMetadata:
+    with urllib.request.urlopen(url) as f:
+        return pydantic.TypeAdapter(RAPIDSMetadata).validate_json(f.read())
+
+
+def fetch_latest() -> RAPIDSMetadata:
+    return _fetch_from_url(_GITHUB_METADATA_URL)

tests/test_remote.py

@@ -0,0 +1,39 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from unittest.mock import patch
+
+from pytest_httpserver import HTTPServer
+from pydantic import TypeAdapter
+
+import rapids_metadata.remote as rapids_remote
+from rapids_metadata import all_metadata
+from rapids_metadata.metadata import RAPIDSMetadata
+
+
+def test_fetch_from_url(httpserver: HTTPServer):
+    httpserver.expect_request("/rapids-metadata.json").respond_with_json(
+        TypeAdapter(RAPIDSMetadata).dump_python(all_metadata)
+    )
+    assert (
+        rapids_remote._fetch_from_url(httpserver.url_for("/rapids-metadata.json"))
+        == all_metadata
+    )
+
+
+def test_fetch_latest():
+    with patch("rapids_metadata.remote._fetch_from_url") as patch_fetch_from_url:
+        return_value = rapids_remote.fetch_latest()
+    patch_fetch_from_url.assert_called_once_with(rapids_remote._GITHUB_METADATA_URL)
+    assert return_value == patch_fetch_from_url()