fix: unify rack middleware_args (#1660)

* refactor: unify rack middleware_args

Ensure rack middleware_args are selected consistently based on
`OTEL_SEMCONV_STABILITY_OPT_IN` environment variable.

* use only middleware_args in sinatra tests

---------

Co-authored-by: Ariel Valentin <arielvalentin@users.noreply.github.com>
Co-authored-by: Kayla Reopelle <87386821+kaylareopelle@users.noreply.github.com>

Author: 3 people

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

@@ -11,21 +11,9 @@ module ActionPack
       class Railtie < ::Rails::Railtie
         config.before_initialize do |app|
           OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.install({})
-
-          stability_opt_in = ENV.fetch('OTEL_SEMCONV_STABILITY_OPT_IN', '')
-          values = stability_opt_in.split(',').map(&:strip)
-
-          rack_middleware_args = if values.include?('http/dup')
-                                   OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_dup
-                                 elsif values.include?('http')
-                                   OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_stable
-                                 else
-                                   OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args
-                                 end
-
           app.middleware.insert_before(
             0,
-            *rack_middleware_args
+            *OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args
           )
         end
       end

instrumentation/rack/lib/opentelemetry/instrumentation/rack/instrumentation.rb

@@ -32,6 +32,11 @@ class Instrumentation < OpenTelemetry::Instrumentation::Base
         # This option is only valid for applications using Rack 2.0 or greater
         option :use_rack_events,          default: true, validate: :boolean
 
+        def middleware_args
+          patch_type = determine_semconv
+          send(:"middleware_args_#{patch_type}")
+        end
+
         # Temporary Helper for Sinatra and ActionPack middleware to use during installation
         #
         # @example Default usage
@@ -40,16 +45,14 @@ class Instrumentation < OpenTelemetry::Instrumentation::Base
         #     run lambda { |_arg| [200, { 'Content-Type' => 'text/plain' }, body] }
         #   end
         # @return [Array] consisting of a middleware and arguments used in rack builders
-        def middleware_args
+        def middleware_args_old
           if config.fetch(:use_rack_events, false) == true && defined?(OpenTelemetry::Instrumentation::Rack::Middlewares::Old::EventHandler)
             [::Rack::Events, [OpenTelemetry::Instrumentation::Rack::Middlewares::Old::EventHandler.new]]
           else
             [OpenTelemetry::Instrumentation::Rack::Middlewares::Old::TracerMiddleware]
           end
         end
 
-        alias middleware_args_old middleware_args
-
         def middleware_args_dup
           if config.fetch(:use_rack_events, false) == true && defined?(OpenTelemetry::Instrumentation::Rack::Middlewares::Dup::EventHandler)
             [::Rack::Events, [OpenTelemetry::Instrumentation::Rack::Middlewares::Dup::EventHandler.new]]

instrumentation/sinatra/lib/opentelemetry/instrumentation/sinatra/instrumentation.rb

@@ -51,19 +51,7 @@ class Instrumentation < OpenTelemetry::Instrumentation::Base
         end
 
         def install_middleware(app)
-          if config[:install_rack]
-            stability_opt_in = ENV.fetch('OTEL_SEMCONV_STABILITY_OPT_IN', '')
-            values = stability_opt_in.split(',').map(&:strip)
-
-            if values.include?('http/dup')
-              app.use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_dup)
-            elsif values.include?('http')
-              app.use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_stable)
-            else
-              app.use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args)
-            end
-          end
-
+          app.use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args) if config[:install_rack]
           app.use(Middlewares::TracerMiddleware)
         end
       end

instrumentation/sinatra/test/opentelemetry/instrumentation/sinatra_dup_http_test.rb

@@ -219,7 +219,7 @@ class CustomError < StandardError; end
       let(:app) do
         apps_to_build = apps
         Rack::Builder.new do
-          use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_dup)
+          use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args)
 
           apps_to_build.each do |root, app|
             map root do

instrumentation/sinatra/test/opentelemetry/instrumentation/sinatra_stable_http_test.rb

@@ -199,7 +199,7 @@ class CustomError < StandardError; end
       let(:app) do
         apps_to_build = apps
         Rack::Builder.new do
-          use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args_stable)
+          use(*OpenTelemetry::Instrumentation::Rack::Instrumentation.instance.middleware_args)
 
           apps_to_build.each do |root, app|
             map root do