1 files changed, 39 insertions, 0 deletions
diff --git a/railties/lib/rails/rack/tagged_logging.rb b/railties/lib/rails/rack/tagged_logging.rb
new file mode 100644
index 0000000000..7980319b37
--- /dev/null
+++ b/railties/lib/rails/rack/tagged_logging.rb
@@ -0,0 +1,39 @@
+module Rails
+  module Rack
+    # Enables easy tagging of any logging activity that occurs within the Rails request cycle. The tags are configured via the
+    # config.log_tags setting. The tags can either be strings, procs taking a request argument, or the symbols :uuid or :subdomain.
+    # The latter two are then automatically expanded to request.uuid and request.subdaomins.first -- the two most common tags
+    # desired in production logs.
+    class TaggedLogging
+      def initialize(app, tags = nil)
+        @app, @tags = app, tags
+      end
+
+      def call(env)
+        if @tags
+          Rails.logger.tagged(compute_tags(env)) { @app.call(env) }
+        else
+          @app.call(env)
+        end
+      end
+      
+      private
+        def compute_tags(env)
+          request = ActionDispatch::Request.new(env)
+
+          @tags.collect do |tag|
+            case tag
+            when Proc
+              tag.call(request)
+            when :uuid
+              request.uuid
+            when :subdomain
+              request.subdomains.first
+            else
+              tag
+            end
+          end
+        end
+    end
+  end
+end