Add helper instrumentation

docs/CHANGELOG.md

@@ -30,6 +30,10 @@ nav_order: 5
 
     *Reegan Viljoen*
 
+* Add helper instrumentation.
+
+    *Reegan Viljoen*
+
 ## 3.13.0
 
 * Add ruby head and YJIT to CI.

docs/guide/instrumentation.md

@@ -29,6 +29,24 @@ ActiveSupport::Notifications.subscribe("render.view_component") do |event| # or
 end
 ```
 
+## Instrument helpers
+
+To enable helpers instrumentation, use the `instrument_helpers` option wich will instrument all helpers used in the rendering of a ViewComponent:
+
+```ruby
+# config/application.rb
+# Enable ActiveSupport notifications for all ViewComponents
+config.view_component.instrument_helpers = true
+config.view_component.use_deprecated_instrumentation_name = false
+```
+
+```ruby
+ActiveSupport::Notifications.subscribe("render.view_component.helpers") do |event| # or !render.view_component
+  event.name    # => "render.view_component"
+  event.payload # => { name: "MyComponent", identifier: "/Users/mona/project/app/components/my_component.rb" }
+end
+```
+
 ## Viewing instrumentation sums in the browser developer tools
 
 When using `render.view_component` with `config.server_timing = true` (default in development) in Rails 7, the browser developer tools display the sum total timing information in Network > Timing under the key `render.view_component`.

lib/view_component/config.rb

@@ -17,6 +17,7 @@ def defaults
           preview_route: "/rails/view_components",
           show_previews_source: false,
           instrumentation_enabled: false,
+          instrument_helpers: false,
           use_deprecated_instrumentation_name: true,
           render_monkey_patch_enabled: true,
           view_component_path: "app/components",
@@ -113,6 +114,11 @@ def defaults
       # Whether ActiveSupport notifications are enabled.
       # Defaults to `false`.
 
+      # @!attribute instrument_helpers
+      # @return [Boolean]
+      # Whether ActiveSupport notifications are enabled for helpers.
+      # Defaults to `false`.
+
       # @!attribute use_deprecated_instrumentation_name
       # @return [Boolean]
       # Whether ActiveSupport Notifications use the private name `"!render.view_component"`

lib/view_component/instrumentation.rb

@@ -20,6 +20,19 @@ def render_in(view_context, &block)
       end
     end
 
+    def helpers
+      super unless ViewComponent::Base.config.instrumentation_helpers
+      ActiveSupport::Notifications.instrument(
+        "#{notification_name}.helpers",
+        {
+          name: self.class.name,
+          identifier: self.class.identifier
+        }
+      ) do
+        super
+      end
+    end
+
     private
 
     def notification_name

test/sandbox/app/components/instrumentation_component.html.erb

@@ -1 +1,2 @@
 <div>hello,world!</div>
+<%= helpers.message %>

test/sandbox/test/instrumentation_test.rb

@@ -29,4 +29,19 @@ def test_instrumentation_with_deprecated_name
     assert_equal(events.size, 1)
     assert_equal("!render.view_component", events[0].name)
   end
+
+  def test_helpers_instrumentation
+    with_config_option(:use_deprecated_instrumentation_name, false) do
+      with_config_option(:instrument_helpers, true) do
+        events = []
+        ActiveSupport::Notifications.subscribe("render.view_component.helpers") do |*args|
+          events << ActiveSupport::Notifications::Event.new(*args)
+        end
+        render_inline(InstrumentationComponent.new)
+
+        assert_equal(events.size, 1)
+        assert_equal("render.view_component.helpers", events[0].name)
+      end
+    end
+  end
 end