Update View Component metric building (#2907)

* Use default `View/component` metric name for unidentified View Components

CHANGELOG.md

@@ -2,7 +2,11 @@
 
 ## dev
 
-Version <dev> resolves a bug in rdkafka instrumentation when using the karafka-rdkafka gem.
+Version <dev> updates View Componment instrumentation to use a default metric name when one is unavaliable and resolves a bug in rdkafka instrumentation when using the karafka-rdkafka gem.  
+
+- **Feature: Use default `View/component` metric name for unidentified View Components**
+
+  Previously, when a View Component metric name could not be identified, the agent would set the name as `nil`. Now, the agent defaults to using `View/component` as the metric name when one can not be identified. [PR#2907](https://github.com/newrelic/newrelic-ruby-agent/pull/2907)
 
 - **Bugfix: Instrumentation errors when using the karafka-rdkafka gem**
 

lib/new_relic/agent/instrumentation/view_component/instrumentation.rb

@@ -10,12 +10,7 @@ def render_in_with_tracing(*args)
       NewRelic::Agent.record_instrumentation_invocation(INSTRUMENTATION_NAME)
 
       begin
-        segment = NewRelic::Agent::Tracer.start_segment(
-          name: metric_name(
-            self.class.respond_to?(:identifier) ? self.class.identifier : nil,
-            self.class.name
-          )
-        )
+        segment = NewRelic::Agent::Tracer.start_segment(name: metric_name)
         yield
       rescue => e
         NewRelic::Agent.notice_error(e)
@@ -25,8 +20,12 @@ def render_in_with_tracing(*args)
       end
     end
 
-    def metric_name(identifier, component)
-      "View/#{metric_path(identifier)}/#{component}"
+    def metric_name
+      "View/#{metric_path(self.class.source_location)}/#{self.class.name}"
+    rescue => e
+      NewRelic::Agent.logger.error('Error identifying View Component metric name', e)
+
+      'View/component'
     end
 
     def metric_path(identifier)

test/multiverse/suites/view_component/view_component_instrumentation_test.rb

@@ -58,14 +58,12 @@ def test_error_raised
     end
   end
 
-  # Test metric name being built when the controller class doesn't respond to :identifier
-  # https://github.com/newrelic/newrelic-ruby-agent/pull/2870
-  def test_the_metric_name_omits_the_identifier_when_absent
+  def test_the_metric_name_records_default_name_on_error
     in_transaction do |txn|
       FAKE_CLASS.render_in_with_tracing { 11 * 38 }
       actual_name = txn.segments.last.name
 
-      assert_equal 'View/component/DummyViewComponentInstrumentationClass', actual_name
+      assert_equal 'View/component', actual_name
     end
   end
 end