Blah, SecureRandom#uuid is not supported in 1.8.7 -- cant wait for Rails 4.0 to drop compatibility with 1.8.x

actionpack/lib/action_dispatch/middleware/request_id.rb

@@ -33,7 +33,7 @@ module ActionDispatch
       end
     
       def internal_request_id
-        SecureRandom.uuid
+        SecureRandom.hex(16)
       end
   end
 end

actionpack/test/dispatch/request_id_test.rb

@@ -14,7 +14,7 @@ class RequestIdTest < ActiveSupport::TestCase
   end
   
   test "generating a request id when none is supplied" do
-    assert_match /\w+-\w+-\w+-\w+-\w+/, stub_request.uuid
+    assert_match /\w+/, stub_request.uuid
   end
 
   private