Allow defining default_tags only for rails group

lib/yabeda/rails/event.rb

@@ -13,7 +13,7 @@ def labels
             format: format,
             method: method,
           }
-          labels.merge(payload.slice(*Yabeda.default_tags.keys - labels.keys))
+          labels.merge(payload.slice(*(Yabeda.default_tags.keys + Yabeda.rails.default_tags.keys) - labels.keys))
         end
       end
 

spec/support/rails_app.rb

@@ -18,6 +18,12 @@ class TestApplication < Rails::Application
 end
 
 class HelloController < ActionController::API
+  def append_info_to_payload(payload)
+    super
+    payload[:custom_tag_from_rails] = "hello-world-from-rails"
+    payload[:custom_tag] = "hello-world"
+  end
+
   def world
     render json: { hello: :world }
   end

spec/yabeda/rails_spec.rb

@@ -46,4 +46,30 @@ def app
         .by(1)
     end
   end
+
+  context "with default_tags set" do
+    before do
+      Yabeda.default_tag :custom_tag, nil
+    end
+
+    it "increments counters for every request" do
+      expect { get "/hello/world" }.to \
+        increment_yabeda_counter(Yabeda.rails.requests_total)
+        .with_tags(custom_tag: "hello-world")
+        .by(1)
+    end
+  end
+
+  context "with ':rails' default_tags set" do
+    before do
+      Yabeda.default_tag :custom_tag_from_rails, nil, group: :rails
+    end
+
+    it "increments counters for every request" do
+      expect { get "/hello/world" }.to \
+        increment_yabeda_counter(Yabeda.rails.requests_total)
+        .with_tags(custom_tag_from_rails: "hello-world-from-rails")
+        .by(1)
+    end
+  end
 end