Prefer request_id over uuid and test the alias

actionpack/lib/action_dispatch/http/request.rb

@@ -50,7 +50,7 @@ def initialize(env)
       @original_fullpath = nil
       @fullpath          = nil
       @ip                = nil
-      @uuid              = nil
+      @request_id        = nil
     end
 
     def check_path_parameters!
@@ -249,11 +249,11 @@ def remote_ip
     #
     # This unique ID is useful for tracing a request from end-to-end as part of logging or debugging.
     # This relies on the rack variable set by the ActionDispatch::RequestId middleware.
-    def uuid
-      @uuid ||= env["action_dispatch.request_id"]
+    def request_id
+      @request_id ||= env["action_dispatch.request_id"]
     end
 
-    alias_method :request_id, :uuid
+    alias_method :uuid, :request_id
 
     # Returns the lowercase name of the HTTP server software.
     def server_software

actionpack/test/dispatch/request_id_test.rb

@@ -2,19 +2,23 @@
 
 class RequestIdTest < ActiveSupport::TestCase
   test "passing on the request id from the outside" do
-    assert_equal "external-uu-rid", stub_request('HTTP_X_REQUEST_ID' => 'external-uu-rid').uuid
+    assert_equal "external-uu-rid", stub_request('HTTP_X_REQUEST_ID' => 'external-uu-rid').request_id
   end
 
   test "ensure that only alphanumeric uurids are accepted" do
-    assert_equal "X-Hacked-HeaderStuff", stub_request('HTTP_X_REQUEST_ID' => '; X-Hacked-Header: Stuff').uuid
+    assert_equal "X-Hacked-HeaderStuff", stub_request('HTTP_X_REQUEST_ID' => '; X-Hacked-Header: Stuff').request_id
   end
 
   test "ensure that 255 char limit on the request id is being enforced" do
-    assert_equal "X" * 255, stub_request('HTTP_X_REQUEST_ID' => 'X' * 500).uuid
+    assert_equal "X" * 255, stub_request('HTTP_X_REQUEST_ID' => 'X' * 500).request_id
   end
 
   test "generating a request id when none is supplied" do
-    assert_match(/\w+-\w+-\w+-\w+-\w+/, stub_request.uuid)
+    assert_match(/\w+-\w+-\w+-\w+-\w+/, stub_request.request_id)
+  end
+
+  test "uuid alias" do
+    assert_equal "external-uu-rid", stub_request('HTTP_X_REQUEST_ID' => 'external-uu-rid').uuid
   end
 
   private

guides/source/rails_on_rack.md

@@ -254,7 +254,7 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol
 
 **`ActionDispatch::RequestId`**
 
-* Makes a unique `X-Request-Id` header available to the response and enables the `ActionDispatch::Request#uuid` method.
+* Makes a unique `X-Request-Id` header available to the response and enables the `ActionDispatch::Request#request_id` method.
 
 **`Rails::Rack::Logger`**
 

railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt

@@ -48,7 +48,7 @@ Rails.application.configure do
   config.log_level = :debug
 
   # Prepend all log lines with the following tags.
-  # config.log_tags = [ :subdomain, :uuid ]
+  # config.log_tags = [ :subdomain, :request_id ]
 
   # Use a different logger for distributed setups.
   # config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)