Apply suggestions from code review

Co-authored-by: Kayla Reopelle <[email protected]>

Author: hannahramadan

instrumentation/action_pack/lib/opentelemetry/instrumentation/action_pack/railtie.rb

@@ -15,22 +15,18 @@ class Railtie < ::Rails::Railtie
           stability_opt_in = ENV.fetch('OTEL_SEMCONV_STABILITY_OPT_IN', '')
           values = stability_opt_in.split(',').map(&:strip)
 
-          if values.include?('http/dup')
-            app.middleware.insert_before(
-              0,
-              *OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_dup
-            )
+          middleware_args = if values.include?('http/dup')
+             OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_dup
           elsif values.include?('http')
-            app.middleware.insert_before(
-              0,
-              *OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_stable
-            )
+            OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_stable
           else
-            app.middleware.insert_before(
-              0,
-              *OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_old
-            )
+            OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_old
           end
+
+           app.middleware.insert_before(
+             0,
+             *middleware_args
+           )
         end
       end
     end

instrumentation/rack/lib/opentelemetry/instrumentation/rack/middlewares/stable/event_handler.rb

@@ -158,12 +158,10 @@ def untraced_request?(env)
               false
             end
 
-            # https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/data-http.md#name
+            # https://opentelemetry.io/docs/specs/semconv/http/http-spans/#name
             #
             # recommendation: span.name(s) should be low-cardinality (e.g.,
             # strip off query param value, keep param name)
-            #
-            # see http://github.com/open-telemetry/opentelemetry-specification/pull/416/files
             def create_request_span_name(request)
               # NOTE: dd-trace-rb has implemented 'quantization' (which lowers url cardinality)
               #       see Datadog::Quantization::HTTP.url
@@ -193,7 +191,7 @@ def request_span_attributes(env)
               }
 
               attributes['url.query'] = env['QUERY_STRING'] unless env['QUERY_STRING'].empty?
-              attributes['http.user_agent'] = env['HTTP_USER_AGENT'] if env['HTTP_USER_AGENT']
+              attributes['user_agent.original'] = env['HTTP_USER_AGENT'] if env['HTTP_USER_AGENT']
               attributes.merge!(extract_request_headers(env))
               attributes
             end

instrumentation/rack/lib/opentelemetry/instrumentation/rack/middlewares/stable/tracer_middleware.rb

@@ -132,7 +132,7 @@ def request_span_attributes(env:)
               }
 
               attributes['url.query'] = env['QUERY_STRING'] unless env['QUERY_STRING'].empty?
-              attributes['http.user_agent'] = env['HTTP_USER_AGENT'] if env['HTTP_USER_AGENT']
+              attributes['user_agent.original'] = env['HTTP_USER_AGENT'] if env['HTTP_USER_AGENT']
               attributes.merge!(allowed_request_headers(env))
             end