fix WPS owslib/pywps mixup between default/data_type as default format of an optional ComplexData input

CHANGES.rst

@@ -16,7 +16,10 @@ Changes:
 
 Fixes:
 ------
-- No change.
+- Fix invalid ``default`` attribute resolution of an optional `WPS` ``ComplexData`` (i.e.: ``minOccurs: 0``) that also
+  provides a ``Default/Format`` in the `XML` process description. When that input was omitted (as permitted) from the
+  execution request, parsing of the `XML` would incorrectly inject the `JSON` representation of the ``Default/Format``
+  as a substitute for the ``default`` value. See ``weaver.processes.convert.ows2json_io`` implementation for details.
 
 .. _changes_5.6.0:
 

tests/functional/test_wps_provider.py

@@ -246,3 +246,80 @@ def test_register_describe_execute_ncdump(self, mock_responses):
             with open(output_path, mode="r", encoding="utf-8") as out_file:
                 data = out_file.read()
             assert data == ncdump_data
+
+    @mocked_remote_server_requests_wps1([
+        resources.TEST_REMOTE_SERVER_URL,
+        resources.TEST_HUMMINGBIRD_WPS1_GETCAP_XML,
+        [resources.TEST_HUMMINGBIRD_DESCRIBE_WPS1_XML],
+    ])
+    def test_register_describe_execute_ncdump_no_default_format(self, mock_responses):
+        """
+        Test a remote :term:`WPS` provider that defines an optional input of ``ComplexData`` type with a default format.
+
+        When the ``ComplexData`` input is omitted (allowed by ``minOccurs=0``), the execution parsing must **NOT**
+        inject an input due to the detection of the default **format** (rather than default data/reference). If an
+        input is erroneously injected, :mod:`pywps` tends to auto-generate an empty file (from the storage linked to
+        the input), which yields an explicitly provided empty string value as ``ComplexData`` input.
+
+        An example of such process is the ``ncdump`` that
+        takes [0-100] ``ComplexData`` AND/OR [0-100] NetCDF OpenDAP URL strings as ``LiteralData``.
+        """
+        self.service_store.clear_services()
+
+        # register the provider
+        remote_provider_name = "test-wps-remote-provider-hummingbird"
+        path = "/providers"
+        data = {"id": remote_provider_name, "url": resources.TEST_REMOTE_SERVER_URL}
+        resp = self.app.post_json(path, params=data, headers=self.json_headers)
+        assert resp.status_code == 201
+
+        exec_path = f"{self.app_url}/providers/{remote_provider_name}/processes/ncdump/execution"
+        exec_file = "http://localhost.com/dont/care.nc"
+        exec_body = {
+            "mode": ExecuteMode.ASYNC,
+            "response": ExecuteResponse.DOCUMENT,
+            "inputs": [{"id": "dataset_opendap", "data": exec_file}],
+            "outputs": [{"id": "output", "transmissionMode": ExecuteTransmissionMode.VALUE}]
+        }
+        status_url = f"{resources.TEST_REMOTE_SERVER_URL}/status.xml"
+        output_url = f"{resources.TEST_REMOTE_SERVER_URL}/output.txt"
+        with open(resources.TEST_HUMMINGBIRD_STATUS_WPS1_XML, mode="r", encoding="utf-8") as status_file:
+            status = status_file.read().format(
+                TEST_SERVER_URL=resources.TEST_REMOTE_SERVER_URL,
+                LOCATION_XML=status_url,
+                OUTPUT_FILE=output_url,
+            )
+
+        ncdump_data = "Fake NetCDF Data"
+        with contextlib.ExitStack() as stack_exec:
+            # mock direct execution bypassing celery
+            for mock_exec in mocked_execute_celery():
+                stack_exec.enter_context(mock_exec)
+            # mock responses expected by "remote" WPS-1 Execute request and relevant documents
+            mock_responses.add("GET", exec_file, body=ncdump_data, headers={"Content-Type": ContentType.APP_NETCDF})
+            mock_responses.add("POST", resources.TEST_REMOTE_SERVER_URL, body=status, headers=self.xml_headers)
+            mock_responses.add("GET", status_url, body=status, headers=self.xml_headers)
+            mock_responses.add("GET", output_url, body=ncdump_data, headers={"Content-Type": ContentType.TEXT_PLAIN})
+
+            # add reference to specific provider class 'dispatch' to validate it was called with expected inputs
+            # (whole procedure must run even though a lot of parts are mocked)
+            # use the last possible method before sendoff to WPS, since filtering of omitted defaults can happen
+            # at the very last moment to accommodate for CWL needing 'null' inputs explicitly in jobs submission
+            real_wps1_process_dispatch = Wps1Process.dispatch
+            handle_wps1_process_dispatch = stack_exec.enter_context(
+                mock.patch.object(Wps1Process, "dispatch", side_effect=real_wps1_process_dispatch, autospec=True)
+            )  # type: MockPatch
+
+            # launch job execution and validate
+            resp = mocked_sub_requests(self.app, "post_json", exec_path, timeout=5,
+                                       data=exec_body, headers=self.json_headers, only_local=True)
+            assert resp.status_code in [200, 201], f"Failed with: [{resp.status_code}]\nReason:\n{resp.json}"
+            assert handle_wps1_process_dispatch.called, "WPS-1 handler should have been called by CWL runner context"
+
+            wps_exec_params = handle_wps1_process_dispatch.call_args_list[0].args
+            wps_exec_inputs = wps_exec_params[1]
+            assert isinstance(wps_exec_inputs, list), "WPS Inputs should have been passed for dispatch as 1st argument."
+            wps_exec_inputs = dict(wps_exec_inputs)
+            assert "dataset_opendap" in wps_exec_inputs, "Explicitly provided WPS inputs should be present."
+            assert "dataset" not in wps_exec_inputs, "Omitted WPS input should not be injected in the request."
+            assert wps_exec_inputs["dataset_opendap"] == exec_file

tests/processes/test_convert.py

@@ -25,6 +25,7 @@
 
 from tests import resources
 from tests.utils import MockedResponse, assert_equal_any_order, mocked_remote_server_requests_wps1
+from weaver import xml_util
 from weaver.exceptions import PackageTypeError
 from weaver.formats import (
     EDAM_MAPPING,
@@ -71,6 +72,7 @@
     json2oas_io,
     json2wps_allowed_values,
     json2wps_datatype,
+    json2wps_io,
     json2wps_supported_uoms,
     merge_io_formats,
     normalize_ordered_io,
@@ -2341,6 +2343,86 @@ def test_ows2json_io_convert_literal_uom(ows_io, json_io):
     assert result == json_io
 
 
+def test_ows_wps_json_default_complex_format():
+    xml_io = xml_util.parse(resources.WPS_COMPLEX_OPTIONAL_IO_XML).xpath("//DataInputs/Input")[0]
+    ows_io = OWSInput(xml_io)
+    res_io = ows2json_io(ows_io)
+    assert res_io == {
+        "id": "test",
+        "title": "test",
+        "min_occurs": 0,
+        "max_occurs": 100,
+        "any_value": False,
+        "type": WPS_COMPLEX_DATA,
+        "data_type": WPS_COMPLEX_DATA,
+        "data_format": {
+            "mimeType": ContentType.APP_NETCDF,
+            "encoding": "base64",
+            "maximumMegabytes": 200,
+            "schema": None,
+            "default": True,
+        },
+        "formats": [
+            {
+                "mimeType": ContentType.APP_NETCDF,
+                "encoding": "base64",
+                "maximumMegabytes": 200,
+                "schema": None,
+                "default": True,
+            },
+            {
+                "mimeType": ContentType.APP_JSON,
+                "encoding": None,
+                "maximumMegabytes": 200,
+                "schema": None,
+                "default": False,
+            },
+        ],
+    }
+
+    wps_io = json2wps_io(res_io, "input")
+    assert wps_io.identifier == "test"
+    assert wps_io.title == "test"
+    assert wps_io.min_occurs == 0
+    assert wps_io.max_occurs == 100
+    assert wps_io.data_format == Format(ContentType.APP_NETCDF, encoding="base64")
+    assert all(wps_fmt == val_fmt for wps_fmt, val_fmt in zip(
+        wps_io.supported_formats,
+        [
+            Format(ContentType.APP_NETCDF, encoding="base64"),
+            Format(ContentType.APP_JSON),
+        ],
+    ))
+
+    # ensure no defaults applied
+    assert wps_io.data is None
+    assert wps_io._default is None
+
+    res_io = wps2json_io(wps_io)
+    assert res_io == {
+        "id": "test",
+        "title": "test",
+        "description": "",
+        "keywords": [],
+        "metadata": [],
+        "translations": None,
+        "asreference": False,
+        "workdir": None,
+        "minOccurs": "0",
+        "maxOccurs": "100",
+        "mode": MODE.NONE,
+        "type": WPS_COMPLEX,
+        "data_format": {"mime_type": ContentType.APP_NETCDF, "encoding": "base64", "schema": "", "extension": ""},
+        "formats": [
+            {"mediaType": ContentType.APP_NETCDF, "encoding": "base64", "schema": "", "extension": "", "default": True},
+            {"mediaType": ContentType.APP_JSON, "encoding": "", "schema": "", "extension": "", "default": False}
+        ],
+        # from default data_format
+        "mimetype": ContentType.APP_NETCDF,
+        "encoding": "base64",
+    }
+
+
 @pytest.mark.parametrize(
     ["value", "dtype", "ctype", "expect"],
     [

tests/resources/__init__.py

@@ -49,6 +49,7 @@
 
 WPS_ENUM_ARRAY_IO_ID = "subset_countries"
 WPS_ENUM_ARRAY_IO_XML = os.path.join(RESOURCES_PATH, "wps_enum_array_io.xml")
+WPS_COMPLEX_OPTIONAL_IO_XML = os.path.join(RESOURCES_PATH, "wps_complex_optional_io.xml")
 WPS_LITERAL_COMPLEX_IO_ID = "ice_days"
 WPS_LITERAL_COMPLEX_IO_XML = os.path.join(RESOURCES_PATH, "wps_literal_complex_io.xml")
 WPS_LITERAL_VALUES_IO_ID = "ensemble_grid_point_cold_spell_duration_index"

tests/resources/wps_complex_optional_io.xml

@@ -0,0 +1,23 @@
+<DataInputs xmlns:ows="http://www.opengis.net/ows/1.1">
+    <Input minOccurs="0" maxOccurs="100">
+        <ows:Identifier>test</ows:Identifier>
+        <ows:Title>test</ows:Title>
+        <ComplexData maximumMegabytes="200">
+            <Default>
+                <Format>
+                    <MimeType>application/x-netcdf</MimeType>
+                    <Encoding>base64</Encoding>
+                </Format>
+            </Default>
+            <Supported>
+                <Format>
+                    <MimeType>application/x-netcdf</MimeType>
+                    <Encoding>base64</Encoding>
+                </Format>
+                <Format>
+                    <MimeType>application/json</MimeType>
+                </Format>
+            </Supported>
+        </ComplexData>
+    </Input>
+</DataInputs>

weaver/processes/convert.py

@@ -397,10 +397,22 @@ def ows2json_io(ows_io):
 
     # add 'format' if missing, derived from other variants
     if io_type == WPS_COMPLEX_DATA:
-        fmt_default = False
+        fmt_default_found = False
         if "default" in json_io and isinstance(json_io["default"], dict):
-            json_io["default"]["default"] = True  # provide for workflow extension (internal), schema drops it (API)
-            fmt_default = True
+            # NOTE:
+            #   When parsing between OWSLib and PyWPS for corresponding 'ComplexData' structures, there is an
+            #   ambiguity in the field names. The OWSLib 'defaultValue' attribute is employed as the "default format"
+            #   to resolve if the **format** was omitted (but only when the input reference/data must is provided!),
+            #   whereas PyWPS uses the attribute named 'data_format' for the applied (or default) format of the input
+            #   reference/data. However, both of these libraries also reuse the 'defaultValue' and 'default' attributes
+            #   respectively for the 'LiteralData' type, where the value is the **actual data** used by default.
+            #   The conversion between those libraries must therefore be careful about these specific field combinations
+            #   to avoid misbehavior when resolving some form of "default" by omission of data/reference/format.
+            #   To be sure, swap the ambiguous 'default' for explicit 'data_format' (where 'data=None' if I/O omitted).
+            fmt_default_value = json_io.pop("default")
+            fmt_default_value["default"] = True  # provide for workflow extension (internal), schema drops it (API)
+            json_io["data_format"] = fmt_default_value
+            fmt_default_found = True
 
         # retrieve alternate format definitions
         if "formats" not in json_io:
@@ -430,13 +442,15 @@ def ows2json_io(ows_io):
 
         # apply the default flag
         for fmt in json_io["formats"]:
-            fmt["default"] = fmt_default and is_equal_formats(json_io["default"], fmt)
+            fmt_default_value = get_field(json_io, "data_format", default={})
+            fmt["default"] = fmt_default_found and is_equal_formats(fmt_default_value, fmt)
             if fmt["default"]:
                 break
 
         # NOTE:
-        #   Don't apply 'minOccurs=0' as in below literal case because default 'format' does not imply that unspecified
+        #   Don't force 'minOccurs=0' as in below literal case because default 'format' does not imply that unspecified
         #   input is valid, but rather that given an input without explicit 'format' specified, that 'default' is used.
+        #   If the I/O is optional, it should have indicated explicitly the 'minOccurs=0' attribute for 'ComplexData'.
         return json_io
 
     # add value constraints in specifications