Trace request attributes before invoking middleware

If an exception is raised in subsequent middlewares, added trace
attributes will still be logged to Azure. This allows us to find
requests that fail in the logs.

pccommon/pccommon/tracing.py

@@ -62,8 +62,7 @@ async def trace_request(
             # are slow.
             request.state.parent_span = span
 
-            response = await call_next(request)
-
+            # Add request dimensions to the trace prior to calling the next middleware
             tracer.add_attribute_to_current_span(
                 attribute_key="ref_id",
                 attribute_value=request.headers.get(X_AZURE_REF),
@@ -76,9 +75,6 @@ async def trace_request(
                 attribute_key="request_ip",
                 attribute_value=get_request_ip(request),
             )
-            tracer.add_attribute_to_current_span(
-                attribute_key=HTTP_STATUS_CODE, attribute_value=response.status_code
-            )
             tracer.add_attribute_to_current_span(
                 attribute_key=HTTP_METHOD, attribute_value=str(request.method)
             )
@@ -103,6 +99,13 @@ async def trace_request(
                         attribute_key="item", attribute_value=item_id
                     )
 
+            # Call next middleware
+            response = await call_next(request)
+
+            # Include response dimensions in the trace
+            tracer.add_attribute_to_current_span(
+                attribute_key=HTTP_STATUS_CODE, attribute_value=response.status_code
+            )
         return response
     else:
         return await call_next(request)