Fix OTLP gRPC metadata key normalization

packages/traceloop-sdk/tests/test_sdk_initialization.py

@@ -86,6 +86,22 @@ def test_grpc_schemes(self, endpoint, expected_endpoint, insecure):
             init_spans_exporter(endpoint, {})
             mock.assert_called_once_with(endpoint=expected_endpoint, headers={}, insecure=insecure)
 
+    def test_grpc_metadata_keys_are_lowercase(self):
+        from traceloop.sdk.tracing.tracing import init_spans_exporter
+        from opentelemetry.exporter.otlp.proto.grpc.trace_exporter import OTLPSpanExporter
+
+        with patch.object(OTLPSpanExporter, "__init__", return_value=None) as mock:
+            init_spans_exporter(
+                "grpc://localhost:4317",
+                {"Authorization": "Bearer test", "X-Api-Key": "test"},
+            )
+
+        mock.assert_called_once_with(
+            endpoint="localhost:4317",
+            headers={"authorization": "Bearer test", "x-api-key": "test"},
+            insecure=True,
+        )
+
     @pytest.mark.parametrize("endpoint,match", [
         ("grpc://collector.example.com:4317", "grpc:// OTLP export is insecure"),
         ("grpc://host.docker.internal:4317", "grpc:// OTLP export is insecure"),
@@ -127,6 +143,24 @@ def test_logging_local_grpc_endpoint_can_be_insecure(self):
             insecure=True,
         )
 
+    @pytest.mark.parametrize("signal", ["metrics", "logging"])
+    def test_grpc_signal_metadata_keys_are_lowercase(self, signal):
+        if signal == "metrics":
+            from traceloop.sdk.metrics.metrics import init_metrics_exporter as factory
+            from opentelemetry.exporter.otlp.proto.grpc.metric_exporter import OTLPMetricExporter as exporter
+        else:
+            from traceloop.sdk.logging.logging import init_logging_exporter as factory
+            from opentelemetry.exporter.otlp.proto.grpc._log_exporter import OTLPLogExporter as exporter
+
+        with patch.object(exporter, "__init__", return_value=None) as mock:
+            factory("grpc://localhost:4317", {"Authorization": "Bearer test"})
+
+        mock.assert_called_once_with(
+            endpoint="localhost:4317",
+            headers={"authorization": "Bearer test"},
+            insecure=True,
+        )
+
     @pytest.mark.parametrize("factory_path,endpoint", [
         ("traceloop.sdk.metrics.metrics.init_metrics_exporter", "grpc://collector.example.com:4317"),
         ("traceloop.sdk.logging.logging.init_logging_exporter", "otlp://collector.example.com:4317"),

packages/traceloop-sdk/traceloop/sdk/exporters/headers.py

@@ -0,0 +1,11 @@
+from typing import Dict
+
+
+def grpc_metadata_headers(headers: Dict[str, str]) -> Dict[str, str]:
+    """Normalize HTTP-style headers for gRPC metadata.
+
+    gRPC metadata keys must be lowercase. The public SDK accepts conventional
+    HTTP casing (for example ``Authorization``), so every gRPC signal exporter
+    must normalize keys before passing them to grpcio.
+    """
+    return {str(key).lower(): str(value) for key, value in headers.items()}

packages/traceloop-sdk/traceloop/sdk/logging/logging.py

@@ -17,6 +17,7 @@
     FortifyRootGRPCLogExporter as GRPCExporter,
     FortifyRootHTTPLogExporter as HTTPExporter,
 )
+from traceloop.sdk.exporters.headers import grpc_metadata_headers
 
 LOCAL_EXPORT_HOSTS = {"localhost"}
 
@@ -139,7 +140,11 @@ def init_logging_exporter(endpoint: str, headers: Dict[str, str]) -> LogExporter
     grpc_endpoint, insecure = _resolve_grpc_exporter_endpoint(trimmed_endpoint)
     return cast(
         LogExporter,
-        GRPCExporter(endpoint=grpc_endpoint, headers=headers, insecure=insecure),
+        GRPCExporter(
+            endpoint=grpc_endpoint,
+            headers=grpc_metadata_headers(headers),
+            insecure=insecure,
+        ),
     )
 
 

packages/traceloop-sdk/traceloop/sdk/metrics/metrics.py

@@ -21,6 +21,7 @@
     FortifyRootGRPCMetricExporter as GRPCExporter,
     FortifyRootHTTPMetricExporter as HTTPExporter,
 )
+from traceloop.sdk.exporters.headers import grpc_metadata_headers
 
 LOCAL_EXPORT_HOSTS = {"localhost"}
 
@@ -125,7 +126,11 @@ def init_metrics_exporter(endpoint: str, headers: Dict[str, str]) -> MetricExpor
             base_url = f"{base_url}/v1/metrics"
         return HTTPExporter(endpoint=base_url, headers=headers)
     grpc_endpoint, insecure = _resolve_grpc_exporter_endpoint(trimmed_endpoint)
-    return GRPCExporter(endpoint=grpc_endpoint, headers=headers, insecure=insecure)
+    return GRPCExporter(
+        endpoint=grpc_endpoint,
+        headers=grpc_metadata_headers(headers),
+        insecure=insecure,
+    )
 
 
 def init_metrics_provider(

packages/traceloop-sdk/traceloop/sdk/tracing/tracing.py

@@ -34,6 +34,7 @@
     FortifyRootGRPCSpanExporter as GRPCExporter,
     FortifyRootHTTPSpanExporter as HTTPExporter,
 )
+from traceloop.sdk.exporters.headers import grpc_metadata_headers
 from traceloop.sdk.tracing.content_allow_list import ContentAllowList
 from traceloop.sdk.utils import is_notebook
 from traceloop.sdk.utils.package_check import is_package_installed
@@ -412,17 +413,23 @@ def init_spans_exporter(api_endpoint: str, headers: Dict[str, str]) -> SpanExpor
         case "grpc":
             grpc_endpoint, insecure = _resolve_grpc_exporter_endpoint(api_endpoint)
             return GRPCExporter(
-                endpoint=grpc_endpoint, headers=headers, insecure=insecure
+                endpoint=grpc_endpoint,
+                headers=grpc_metadata_headers(headers),
+                insecure=insecure,
             )
         case "grpcs":
             grpc_endpoint, insecure = _resolve_grpc_exporter_endpoint(api_endpoint)
             return GRPCExporter(
-                endpoint=grpc_endpoint, headers=headers, insecure=insecure
+                endpoint=grpc_endpoint,
+                headers=grpc_metadata_headers(headers),
+                insecure=insecure,
             )
         case _:
             grpc_endpoint, insecure = _resolve_grpc_exporter_endpoint(api_endpoint)
             return GRPCExporter(
-                endpoint=grpc_endpoint, headers=headers, insecure=insecure
+                endpoint=grpc_endpoint,
+                headers=grpc_metadata_headers(headers),
+                insecure=insecure,
             )