fix(observability): resolve the OpenInference span kind from the configured span prefix

packages/nvidia_nat_opentelemetry/src/nat/plugins/opentelemetry/span_converter.py

@@ -20,6 +20,7 @@
 from openinference.semconv.trace import SpanAttributes
 
 from nat.data_models.span import Span
+from nat.data_models.span import SpanAttributes as NatSpanAttributes
 from nat.data_models.span import SpanStatusCode
 from nat.plugins.opentelemetry.otel_span import OtelSpan
 from opentelemetry.trace import SpanContext
@@ -190,7 +191,7 @@ def convert_span_to_otel(nat_span: Span) -> OtelSpan:
     otel_span._status_description = None
 
     # Set span kind efficiently (direct attribute modification)
-    event_type = nat_span.attributes.get("nat.event_type", "UNKNOWN")
+    event_type = nat_span.attributes.get(NatSpanAttributes.NAT_EVENT_TYPE.value, "UNKNOWN")
     span_kind = SPAN_EVENT_TYPE_TO_SPAN_KIND_MAP.get(event_type, OpenInferenceSpanKindValues.UNKNOWN)
     otel_span._attributes[SpanAttributes.OPENINFERENCE_SPAN_KIND] = span_kind.value
 

packages/nvidia_nat_opentelemetry/tests/observability/test_span_converter.py

@@ -0,0 +1,96 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# 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 importlib
+import os
+
+import pytest
+from openinference.semconv.trace import OpenInferenceSpanKindValues
+from openinference.semconv.trace import SpanAttributes as OpenInferenceSpanAttributes
+
+import nat.data_models.span as nat_span_module
+from nat.plugins.opentelemetry.span_converter import convert_span_to_otel
+
+_CONVERTER_MODULE = "nat.plugins.opentelemetry.span_converter"
+
+
+@pytest.fixture
+def reloaded_with_span_prefix(request):
+    """Reload the NAT span modules with ``NAT_SPAN_PREFIX`` set.
+
+    ``SpanAttributes`` is built at import time, so honoring a custom prefix requires reloading both
+    the module that defines the attribute keys and the converter that reads them. The original
+    environment and module objects are restored on teardown.
+    """
+    prefix = request.param
+
+    original_prefix = os.environ.get("NAT_SPAN_PREFIX")
+    os.environ["NAT_SPAN_PREFIX"] = prefix
+    try:
+        span_module = importlib.reload(nat_span_module)
+        converter_module = importlib.reload(importlib.import_module(_CONVERTER_MODULE))
+        yield span_module, converter_module
+    finally:
+        if original_prefix is None:
+            os.environ.pop("NAT_SPAN_PREFIX", None)
+        else:
+            os.environ["NAT_SPAN_PREFIX"] = original_prefix
+        importlib.reload(nat_span_module)
+        importlib.reload(importlib.import_module(_CONVERTER_MODULE))
+
+
+@pytest.mark.parametrize("reloaded_with_span_prefix", ["nat"], indirect=True)
+def test_converted_span_kind_with_default_prefix(reloaded_with_span_prefix):
+    """A span tagged with the default ``nat`` prefix keeps its OpenInference span kind.
+
+    The modules are reloaded with ``NAT_SPAN_PREFIX`` pinned to ``nat`` so the assertion does not
+    depend on the prefix the test process happens to start with.
+    """
+    span_module, converter_module = reloaded_with_span_prefix
+
+    nat_span = span_module.Span(name="llm", attributes={"nat.event_type": "LLM_START"})
+
+    otel_span = converter_module.convert_span_to_otel(nat_span)
+
+    assert otel_span.attributes[OpenInferenceSpanAttributes.OPENINFERENCE_SPAN_KIND] == (
+        OpenInferenceSpanKindValues.LLM.value)
+
+
+@pytest.mark.parametrize("reloaded_with_span_prefix", ["nat", "custom", "prod.service"], indirect=True)
+def test_converted_span_kind_uses_configured_span_prefix(reloaded_with_span_prefix):
+    """The OpenInference span kind is resolved from the configured span prefix.
+
+    ``SpanExporter`` writes the event type under ``f"{NAT_SPAN_PREFIX}.event_type"``, so a prefix
+    other than the default must not degrade every span to ``UNKNOWN``.
+    """
+    span_module, converter_module = reloaded_with_span_prefix
+
+    event_type_key = span_module.SpanAttributes.NAT_EVENT_TYPE.value
+    nat_span = span_module.Span(name="llm", attributes={event_type_key: "LLM_START"})
+
+    otel_span = converter_module.convert_span_to_otel(nat_span)
+
+    assert otel_span.attributes[OpenInferenceSpanAttributes.OPENINFERENCE_SPAN_KIND] == (
+        OpenInferenceSpanKindValues.LLM.value)
+
+
+def test_converted_span_kind_without_event_type_is_unknown():
+    """A span carrying no event type attribute is reported as ``UNKNOWN``."""
+    nat_span = nat_span_module.Span(name="opaque", attributes={})
+
+    otel_span = convert_span_to_otel(nat_span)
+
+    assert otel_span.attributes[OpenInferenceSpanAttributes.OPENINFERENCE_SPAN_KIND] == (
+        OpenInferenceSpanKindValues.UNKNOWN.value)