Issue #668 federation extension: cover "federation:backends" on POST /validation

Author: soxofaan

openeo/rest/_testing.py

@@ -277,7 +277,10 @@ def _handle_post_validation(self, request, context):
         """Handler of `POST /validation` (validate process graph)."""
         pg = request.json()["process_graph"]
         self.validation_requests.append(pg)
-        return {"errors": self.next_validation_errors}
+        if isinstance(self.next_validation_errors, list):
+            return {"errors": self.next_validation_errors}
+        else:
+            return self.next_validation_errors
 
     def get_sync_pg(self) -> dict:
         """Get one and only synchronous process graph"""

openeo/rest/connection.py

@@ -70,6 +70,7 @@
     CollectionListingResponse,
     JobListingResponse,
     ProcessListingResponse,
+    ValidationResponse,
 )
 from openeo.rest.service import Service
 from openeo.rest.udp import Parameter, RESTUserDefinedProcess
@@ -965,7 +966,7 @@ def user_defined_process(self, user_defined_process_id: str) -> RESTUserDefinedP
 
     def validate_process_graph(
         self, process_graph: Union[dict, FlatGraphableMixin, str, Path, List[FlatGraphableMixin]]
-    ) -> List[dict]:
+    ) -> ValidationResponse:
         """
         Validate a process graph without executing it.
 
@@ -979,7 +980,8 @@ def validate_process_graph(
         :return: list of errors (dictionaries with "code" and "message" fields)
         """
         pg_with_metadata = self._build_request_with_process_graph(process_graph)["process"]
-        return self.post(path="/validation", json=pg_with_metadata, expected_status=200).json()["errors"]
+        data = self.post(path="/validation", json=pg_with_metadata, expected_status=200).json()
+        return ValidationResponse(response_data=data)
 
     @property
     def _api_version(self) -> ComparableVersion:

openeo/rest/models/federation_extension.py

@@ -26,3 +26,13 @@ def get_federation_missing(data: dict, *, resource_name: str, auto_warn: bool =
     if auto_warn and missing:
         _log.warning(f"Partial {resource_name}: missing federation components: {missing!r}.")
     return missing
+
+
+def get_federation_backends(data: dict) -> Union[List[str], None]:
+    """
+    Get "federation:backends" field from response data, if present.
+    :param data: response data
+    :return:
+    """
+    backends = data.get("federation:backends", None)
+    return backends

openeo/rest/models/general.py

@@ -263,3 +263,39 @@ def ext_federation_missing(self, *, auto_warn: bool = False) -> Union[None, List
         return federation_extension.get_federation_missing(
             data=self._data, resource_name="log listing", auto_warn=auto_warn
         )
+
+
+class ValidationResponse(list):
+    """
+    Container for process metadata listing received
+    from a ``POST /validation`` request.
+
+    .. note::
+        This object mimics, for backward compatibility reasons,
+        the interface of simple list of validation error dictionaries (``List[dict]``),
+        :py:meth:`~openeo.rest.connection.Connection.validate_process_graph()`,
+        but now also provides methods/properties to access additional response data.
+
+    :param response_data: response data from a ``POST /validation`` request
+
+    .. seealso:: :py:meth:`openeo.rest.connection.Connection.validate_process_graph()`
+
+    .. versionadded:: 0.38.0
+    """
+
+    __slots__ = ["_data"]
+
+    def __init__(self, response_data: dict):
+        self._data = response_data
+        # Mimic original list of validation error dictionaries
+        super().__init__(response_data["errors"])
+
+    def ext_federation_backends(self) -> Union[None, List[str]]:
+        """
+        Get "federation:backends" value from validation response.
+
+        .. seealso:: :ref:`federation-extension`
+
+        .. warning:: this API is experimental and subject to change.
+        """
+        return federation_extension.get_federation_backends(data=self._data)

tests/rest/test_connection.py

@@ -4597,3 +4597,40 @@ def test_web_editor(requests_mock):
     con = Connection(API_URL)
     assert con.web_editor() == "https://editor.openeo.org/?server=https%3A%2F%2Foeo.test%2F"
     assert con.web_editor(anonymous=True) == "https://editor.openeo.org/?server=https%3A%2F%2Foeo.test%2F&discover=1"
+
+
+def test_validate_process_graph(con120, dummy_backend):
+    dummy_backend.next_validation_errors = [{"code": "OddSupport", "message": "Odd values are not supported."}]
+    cube = con120.load_collection("S2")
+    res = con120.validate_process_graph(cube)
+    assert res == [{"code": "OddSupport", "message": "Odd values are not supported."}]
+
+
+@pytest.mark.parametrize(
+    ["validation_response", "expected_errors", "expected_backends"],
+    [
+        (
+            {"errors": []},
+            [],
+            None,
+        ),
+        (
+            {"errors": [], "federation:backends": ["oeoa", "oeob"]},
+            [],
+            ["oeoa", "oeob"],
+        ),
+        (
+            {"errors": [{"code": "Nope", "message": "Nope!"}], "federation:backends": ["oeoa", "oeob"]},
+            [{"code": "Nope", "message": "Nope!"}],
+            ["oeoa", "oeob"],
+        ),
+    ],
+)
+def test_validate_process_graph_extra_metadata(
+    con120, dummy_backend, validation_response, expected_errors, expected_backends
+):
+    dummy_backend.next_validation_errors = validation_response
+    cube = con120.load_collection("S2")
+    res = con120.validate_process_graph(cube)
+    assert res == expected_errors
+    assert res.ext_federation_backends() == expected_backends