feat(frontend): Add better frontend tracing (#11244)

* add better tracing through the frontend

* extend allowed headers

* add endpoint to end the trace

* end traces correctly in backend

* end trace

* early cop-out if not tracing is enabled

* Update API version link for v447

src/backend/InvenTree/InvenTree/api_version.py

@@ -1,11 +1,14 @@
 """InvenTree API version information."""
 
 # InvenTree API version
-INVENTREE_API_VERSION = 452
+INVENTREE_API_VERSION = 453
 """Increment this API version number whenever there is a significant change to the API that any clients need to know about."""
 
 INVENTREE_API_TEXT = """
 
+v453 -> 2026-02-11 : https://github.com/inventree/InvenTree/pull/11244
+    - Adds (internal) endpoint to end a observability tooling session
+
 v452 -> 2026-02-10 : https://github.com/inventree/InvenTree/pull/11276
     - Adds "install_into_detail" field to the BuildItem API endpoint
 

src/backend/InvenTree/InvenTree/settings.py

@@ -1289,10 +1289,12 @@ CORS_ALLOWED_ORIGIN_REGEXES = get_setting(
     typecast=list,
 )
 
+_allowed_headers = (*default_cors_headers, 'traceparent')
 # Allow extra CORS headers in DEBUG mode
 # Required for serving /static/ and /media/ files
 if DEBUG:
-    CORS_ALLOW_HEADERS = (*default_cors_headers, 'cache-control', 'pragma', 'expires')
+    _allowed_headers = (*_allowed_headers, 'cache-control', 'pragma', 'expires')
+CORS_ALLOW_HEADERS = _allowed_headers
 
 # In debug mode allow CORS requests from localhost
 # This allows connection from the frontend development server

src/backend/InvenTree/common/api.py

@@ -22,6 +22,7 @@ from django_q.tasks import async_task
 from djmoney.contrib.exchange.models import ExchangeBackend, Rate
 from drf_spectacular.utils import OpenApiResponse, extend_schema
 from error_report.models import Error
+from opentelemetry import trace
 from pint._typing import UnitLike
 from rest_framework import generics, serializers
 from rest_framework.exceptions import NotAcceptable, NotFound, PermissionDenied
@@ -1115,6 +1116,50 @@ class HealthCheckView(APIView):
         )
 
 
+class ObservabilityEndSerializer(serializers.Serializer):
+    """Serializer for observability end endpoint."""
+
+    traceid = serializers.CharField(
+        help_text='Trace ID to end', max_length=128, required=True
+    )
+    service = serializers.CharField(
+        help_text='Service name', max_length=128, required=True
+    )
+
+
+class ObservabilityEnd(CreateAPI):
+    """Endpoint for observability tools."""
+
+    permission_classes = [AllowAnyOrReadScope]
+    serializer_class = ObservabilityEndSerializer
+
+    def create(self, request, *args, **kwargs):
+        """End a trace in the observability system."""
+        if not settings.TRACING_ENABLED:
+            return Response({'status': 'ok'})
+
+        data = self.get_serializer(data=request.data)
+        data.is_valid(raise_exception=True)
+
+        traceid = data.validated_data['traceid']
+        # service = data.validated_data['service']  # This will become interesting with frontend observability
+
+        # End the foreign trend via the low level otel API
+        tracer = trace.get_tracer(__name__)
+        span_context = trace.SpanContext(
+            trace_id=int(traceid, 16),
+            span_id=0,
+            is_remote=True,
+            trace_flags=trace.TraceFlags(0x01),
+            trace_state=trace.TraceState(),
+        )
+        with tracer.start_span('Ending session') as span:
+            span.add_event('Ending external trace')
+            span.add_link(span_context)
+
+        return Response({'status': 'ok'})
+
+
 selection_urls = [
     path(
         '<int:pk>/',
@@ -1393,7 +1438,22 @@ common_api_urls = [
     # System APIs (related to basic system functions)
     path(
         'system/',
-        include([path('health/', HealthCheckView.as_view(), name='api-system-health')]),
+        include([
+            # Health check
+            path('health/', HealthCheckView.as_view(), name='api-system-health')
+        ]),
+    ),
+    # Internal System APIs - DO NOT USE
+    path(
+        'system-internal/',
+        include([
+            # Observability
+            path(
+                'observability/end',
+                ObservabilityEnd.as_view(),
+                name='api-system-observability',
+            )
+        ]),
     ),
 ]