ViewComponent base instrumentation

.rubocop_todo.yml

@@ -24,6 +24,11 @@ Metrics/AbcSize:
     - lib/new_relic/cli/commands/deployments.rb
     - test/**/*
 
+# Offense count: 1
+Metrics/CollectionLiteralLength:
+  Exclude:
+    - 'lib/new_relic/agent/configuration/default_source.rb'
+
 # Offense count: 7
 Minitest/AssertRaisesCompoundBody:
   Exclude:

lib/new_relic/agent/configuration/default_source.rb

@@ -1657,6 +1657,13 @@ def self.enforce_fallback(allowed_values: nil, fallback: nil)
           :allowed_from_server => false,
           :description => 'Controls auto-instrumentation of Stripe at startup. May be one of: `enabled`, `disabled`.'
         },
+        :'instrumentation.view_component' => {
+          :default => 'enabled',
+          :public => true,
+          :type => String,
+          :allowed_from_server => false,
+          :description => 'Controls auto-instrumentation of ViewComponent at startup. May be one of: `enabled`, `disabled`.'
+        },
         :'stripe.user_data.include' => {
           default: NewRelic::EMPTY_ARRAY,
           public: true,

lib/new_relic/agent/instrumentation/view_component.rb

@@ -0,0 +1,30 @@
+# This file is distributed under New Relic's license terms.
+# See https://github.com/newrelic/newrelic-ruby-agent/blob/main/LICENSE for complete details.
+# frozen_string_literal: true
+
+require_relative 'view_component/instrumentation'
+require_relative 'view_component/chain'
+require_relative 'view_component/prepend'
+
+DependencyDetection.defer do
+  named :'view_component'
+
+  depends_on do
+    NewRelic::Agent.config[:'instrumentation.view_component'] == 'enabled'
+  end
+
+  depends_on do
+    defined?(ViewComponent) &&
+      ViewComponent::Base.method_defined?(:render_in)
+  end
+
+  executes do
+    NewRelic::Agent.logger.info('Installing view_component instrumentation')
+
+    if use_prepend?
+      prepend_instrument ViewComponent::Base, NewRelic::Agent::Instrumentation::ViewComponent::Prepend
+    else
+      chain_instrument NewRelic::Agent::Instrumentation::ViewComponent::Chain
+    end
+  end
+end

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

@@ -0,0 +1,21 @@
+# This file is distributed under New Relic's license terms.
+# See https://github.com/newrelic/newrelic-ruby-agent/blob/main/LICENSE for complete details.
+# frozen_string_literal: true
+
+module NewRelic::Agent::Instrumentation
+  module ViewComponent::Chain
+    def self.instrument!
+      ::ViewComponent.class_eval do
+        include NewRelic::Agent::Instrumentation::ViewComponent
+
+        alias_method(:render_in_without_tracing, :render_in)
+
+        def render_in(*args)
+          render_in_with_tracing(*args) do
+            render_in_without_tracing(*args)
+          end
+        end
+      end
+    end
+  end
+end

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

@@ -0,0 +1,40 @@
+# This file is distributed under New Relic's license terms.
+# See https://github.com/newrelic/newrelic-ruby-agent/blob/main/LICENSE for complete details.
+# frozen_string_literal: true
+
+module NewRelic::Agent::Instrumentation
+  module ViewComponent
+    INSTRUMENTATION_NAME = 'view_component'
+
+    def render_in_with_tracing(*args)
+      NewRelic::Agent.record_instrumentation_invocation(INSTRUMENTATION_NAME)
+
+      component = self.class.name
+      identifier = self.class.identifier
+
+      segment = NewRelic::Agent::Tracer.start_segment(
+        name: metric_name(identifier, component)
+      )
+
+      begin
+        NewRelic::Agent::Tracer.capture_segment_error(segment) { yield }
+      ensure
+        NewRelic::Agent::Transaction::Segment.finish(segment)
+      end
+    end
+
+    def metric_name(identifier, component)
+      "View/#{metric_path(identifier)}/#{component}"
+    end
+
+    def metric_path(identifier)
+      if identifier.nil?
+        'component'
+      elsif identifier && (parts = identifier.split('/')).size > 1
+        parts[-2..-1].join('/') # Get filepath by assuming the Rails' structure: app/components/home/example_component.rb
+      else
+        NewRelic::Agent::UNKNOWN_METRIC
+      end
+    end
+  end
+end

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

@@ -0,0 +1,13 @@
+# This file is distributed under New Relic's license terms.
+# See https://github.com/newrelic/newrelic-ruby-agent/blob/main/LICENSE for complete details.
+# frozen_string_literal: true
+
+module NewRelic::Agent::Instrumentation
+  module ViewComponent::Prepend
+    include NewRelic::Agent::Instrumentation::ViewComponent
+
+    def render_in(*args)
+      render_in_with_tracing(*args) { super }
+    end
+  end
+end

test/multiverse/suites/view_component/config/newrelic.yml

@@ -0,0 +1,19 @@
+---
+development:
+  error_collector:
+    enabled: true
+  apdex_t: 0.5
+  monitor_mode: true
+  license_key: bootstrap_newrelic_admin_license_key_000
+  instrumentation:
+    view_component: <%= $render_in %>
+  app_name: test
+  log_level: debug
+  host: 127.0.0.1
+  api_host: 127.0.0.1
+  transaction_trace:
+    record_sql: obfuscated
+    enabled: true
+    stack_trace_threshold: 0.5
+    transaction_threshold: 1.0
+  capture_params: false

test/multiverse/suites/view_component/view_component_instrumentation_test.rb

@@ -0,0 +1,15 @@
+# This file is distributed under New Relic's license terms.
+# See https://github.com/newrelic/newrelic-ruby-agent/blob/main/LICENSE for complete details.
+# frozen_string_literal: true
+
+class ViewComponentInstrumentationTest < Minitest::Test
+  def setup
+    @stats_engine = NewRelic::Agent.instance.stats_engine
+  end
+
+  def teardown
+    NewRelic::Agent.instance.stats_engine.clear_stats
+  end
+
+  # Add tests here
+end