Merge pull request #2572 from ViewComponent/copilot/add-event-emission-for-view-file

Instrumentation: include view template path in `render.view_component` payload

Author: joelhawksley

docs/CHANGELOG.md

@@ -10,6 +10,10 @@ nav_order: 6
 
 ## main
 
+* Add `view_identifier` to the `render.view_component` instrumentation event payload, containing the path to the component's template file (e.g. `app/components/my_component.html.erb`). For components using inline render methods, `view_identifier` will be `nil`.
+
+    *GitHub Copilot*
+
 * Replace deprecated `require_dependency` with `require` in preview loading.
 
     *GitHub Copilot*

docs/guide/instrumentation.md

@@ -22,7 +22,7 @@ Subscribe to the event:
 ```ruby
 ActiveSupport::Notifications.subscribe("render.view_component") do |event| # or !render.view_component
   event.name    # => "render.view_component"
-  event.payload # => { name: "MyComponent", identifier: "/Users/mona/project/app/components/my_component.rb" }
+  event.payload # => { name: "MyComponent", identifier: "/Users/mona/project/app/components/my_component.rb", view_identifier: "/Users/mona/project/app/components/my_component.html.erb" }
 end
 ```
 

lib/view_component/instrumentation.rb

@@ -11,15 +11,28 @@ def self.included(mod)
     def render_in(view_context, &block)
       return super if !Rails.application.config.view_component.instrumentation_enabled.present?
 
+      payload = {
+        name: self.class.name,
+        identifier: self.class.identifier,
+        view_identifier: nil
+      }
+
       ActiveSupport::Notifications.instrument(
         "render.view_component",
-        {
-          name: self.class.name,
-          identifier: self.class.identifier
-        }
+        payload
       ) do
-        super
+        result = super
+        payload[:view_identifier] = @__vc_instrumentation_view_identifier
+        result
       end
+    ensure
+      @__vc_instrumentation_view_identifier = nil
+    end
+
+    def around_render
+      result = super
+      @__vc_instrumentation_view_identifier = current_template&.path
+      result
     end
   end
 end

test/sandbox/test/instrumentation_test.rb

@@ -16,6 +16,7 @@ def test_instrumentation_for_include
     assert_equal("render.view_component", events[0].name)
     assert_equal(events[0].payload[:name], "InstrumentationComponent")
     assert_match("app/components/instrumentation_component.rb", events[0].payload[:identifier])
+    assert_match("app/components/instrumentation_component.html.erb", events[0].payload[:view_identifier])
   end
 
   def test_instrumentation_disabled