Add support for ActiveSupport::EventReporter

.changesets/report-events-from-rails-8-1-s-activesupport--eventreporter-as-logs.md

@@ -0,0 +1,6 @@
+---
+bump: minor
+type: add
+---
+
+Report events from Rails 8.1's Structured Event Reporting (`ActiveSupport::EventReporter`) as logs.

lib/appsignal/config.rb

@@ -102,6 +102,7 @@ def dsl_config_file?
       :enable_gvl_global_timer => true,
       :enable_gvl_waiting_threads => true,
       :enable_rails_error_reporter => true,
+      :enable_active_support_event_log_reporter => true,
       :enable_rake_performance_instrumentation => false,
       :endpoint => "https://push.appsignal.com",
       :files_world_accessible => true,
@@ -184,6 +185,7 @@ def dsl_config_file?
       :enable_gvl_global_timer => "APPSIGNAL_ENABLE_GVL_GLOBAL_TIMER",
       :enable_gvl_waiting_threads => "APPSIGNAL_ENABLE_GVL_WAITING_THREADS",
       :enable_rails_error_reporter => "APPSIGNAL_ENABLE_RAILS_ERROR_REPORTER",
+      :enable_active_support_event_log_reporter => "APPSIGNAL_ENABLE_ACTIVE_SUPPORT_EVENT_LOG_REPORTER",
       :enable_rake_performance_instrumentation =>
         "APPSIGNAL_ENABLE_RAKE_PERFORMANCE_INSTRUMENTATION",
       :files_world_accessible => "APPSIGNAL_FILES_WORLD_ACCESSIBLE",
@@ -802,6 +804,8 @@ def activate_if_environment(*envs)
       #   @return [Boolean] Configure whether GVL waiting threads instrumentation is enabled
       # @!attribute [rw] enable_rails_error_reporter
       #   @return [Boolean] Configure whether Rails error reporter integration is enabled
+      # @!attribute [rw] enable_active_support_event_log_reporter
+      #   @return [Boolean] Configure whether ActiveSupport::EventReporter integration is enabled
       # @!attribute [rw] enable_rake_performance_instrumentation
       #   @return [Boolean] Configure whether Rake performance instrumentation is enabled
       # @!attribute [rw] files_world_accessible

lib/appsignal/hooks.rb

@@ -79,6 +79,7 @@ def truncate(text)
 require "appsignal/hooks/action_mailer"
 require "appsignal/hooks/active_job"
 require "appsignal/hooks/active_support_notifications"
+require "appsignal/hooks/active_support_event_reporter"
 require "appsignal/hooks/celluloid"
 require "appsignal/hooks/code_ownership"
 require "appsignal/hooks/delayed_job"

lib/appsignal/hooks/active_support_event_reporter.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Appsignal
+  class Hooks
+    # @!visibility private
+    class ActiveSupportEventReporterHook < Appsignal::Hooks::Hook
+      register :active_support_event_reporter
+
+      def dependencies_present?
+        defined?(::ActiveSupport::EventReporter) &&
+          Appsignal.config &&
+          Appsignal.config[:enable_active_support_event_log_reporter]
+      end
+
+      def install
+        require "appsignal/integrations/active_support_event_reporter"
+        Rails.event.subscribe(Appsignal::Integrations::ActiveSupportEventReporter::Subscriber.new())
+      end
+    end
+  end
+end

lib/appsignal/integrations/active_support_event_reporter.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module Appsignal
+  module Integrations
+    # @!visibility private
+    module ActiveSupportEventReporter
+      class Subscriber
+        def initialize
+          @logger = Appsignal::Logger.new("rails_events")
+        end
+
+        def emit(event)
+          @logger.info(event[:name], event[:payload])
+        end
+      end
+    end
+  end
+end

spec/lib/appsignal/config_spec.rb

@@ -720,6 +720,7 @@ def on_load
         :enable_minutely_probes => false,
         :enable_nginx_metrics => false,
         :enable_rails_error_reporter => false,
+        :enable_active_support_event_log_reporter => false,
         :enable_rake_performance_instrumentation => false,
         :enable_statsd => false,
         :endpoint => "https://test.appsignal.com",
@@ -792,6 +793,7 @@ def on_load
         "APPSIGNAL_ENABLE_MINUTELY_PROBES" => "false",
         "APPSIGNAL_ENABLE_NGINX_METRICS" => "false",
         "APPSIGNAL_ENABLE_RAILS_ERROR_REPORTER" => "false",
+        "APPSIGNAL_ENABLE_ACTIVE_SUPPORT_EVENT_LOG_REPORTER" => "false",
         "APPSIGNAL_ENABLE_RAKE_PERFORMANCE_INSTRUMENTATION" => "false",
         "APPSIGNAL_ENABLE_STATSD" => "false",
         "APPSIGNAL_FILES_WORLD_ACCESSIBLE" => "false",
@@ -926,6 +928,7 @@ def on_load
         :enable_statsd                  => true,
         :enable_nginx_metrics           => false,
         :enable_rails_error_reporter    => true,
+        :enable_active_support_event_log_reporter => true,
         :enable_rake_performance_instrumentation => false,
         :endpoint                       => "https://push.appsignal.com",
         :files_world_accessible         => true,

spec/lib/appsignal/hooks/active_support_event_reporter_spec.rb

@@ -0,0 +1,67 @@
+describe Appsignal::Hooks::ActiveSupportEventReporterHook do
+  begin
+    require "active_support/event_reporter"
+  rescue LoadError # rubocop:disable Lint/SuppressedException
+  end
+
+  describe "#dependencies_present?" do
+    if DependencyHelper.rails8_1_present?
+      context "when ActiveSupport::EventReporter is present" do
+        context "with enable_active_support_event_log_reporter enabled" do
+          before { start_agent }
+
+          it "returns true" do
+            expect(described_class.new.dependencies_present?).to be_truthy
+          end
+        end
+
+        context "with enable_active_support_event_log_reporter disabled" do
+          before do
+            ENV["APPSIGNAL_ENABLE_ACTIVE_SUPPORT_EVENT_LOG_REPORTER"] = "false"
+            start_agent
+          end
+
+          it "returns false" do
+            expect(described_class.new.dependencies_present?).to be_falsy
+          end
+        end
+      end
+    else
+      context "when ActiveSupport::EventReporter is not present" do
+        subject { described_class.new.dependencies_present? }
+
+        it { is_expected.to be_falsy }
+      end
+    end
+  end
+
+  if defined?(::ActiveSupport::EventReporter)
+    describe "#install" do
+      before do
+        # Mock Rails.event
+        subscribers = []
+        mock_event_reporter = instance_double(
+          "ActiveSupport::EventReporter",
+          :subscribe => nil,
+          :subscribers => subscribers
+        )
+
+        allow(mock_event_reporter).to receive(:subscribe) do |subscriber|
+          subscribers << subscriber
+        end
+
+        allow(Rails).to receive(:event).and_return(mock_event_reporter)
+      end
+
+      it "subscribes the ActiveSupportEventReporter::Subscriber to Rails.event" do
+        event_reporter = Rails.event
+        expect(event_reporter.subscribers).to be_empty
+
+        described_class.new.install
+
+        expect(event_reporter.subscribers.length).to eq(1)
+        expect(event_reporter.subscribers.first).to be_a(Appsignal::Integrations::ActiveSupportEventReporter::Subscriber)
+      end
+    end
+  end
+end

spec/lib/appsignal/integrations/active_support_event_reporter_spec.rb

@@ -0,0 +1,24 @@
+require "appsignal/integrations/active_support_event_reporter"
+
+describe Appsignal::Integrations::ActiveSupportEventReporter::Subscriber do
+  let(:subscriber) { described_class.new }
+  let(:logger) { instance_double(Appsignal::Logger) }
+
+  before do
+    start_agent
+    allow(Appsignal::Logger).to receive(:new).with("rails_events").and_return(logger)
+  end
+
+  describe "#emit" do
+    it "logs the event name and payload" do
+      event = {
+        :name => "user.created",
+        :payload => { :id => 123, :email => "user@example.com" },
+      }
+
+      expect(logger).to receive(:info).with("user.created", { :id => 123, :email => "user@example.com" })
+
+      subscriber.emit(event)
+    end
+  end
+end

spec/support/helpers/dependency_helper.rb

@@ -49,6 +49,10 @@ def rails7_1_present?
     rails_present? && rails_version >= Gem::Version.new("7.1.0")
   end
 
+  def rails8_1_present?
+    rails_present? && rails_version >= Gem::Version.new("8.1.0")
+  end
+
   def active_job_wraps_args?
     rails7_present? || (ruby_3_1_or_newer? && rails6_1_present? && !rails6_1_5_present?)
   end