Merge pull request #2239 from newrelic/ignore_non_server_rails_commands

Disable autostart for non 'server' Rails commands

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 Version <dev> brings support for gleaning a Docker container id from cgroups v2 based containers and records additional synthetics attributes.
 
+- **Feature: Prevent the agent from starting in rails commands in Rails 7**
+
+  Previously, the agent ignored many Rails commands by default, such as `rails routes`, using Rake-specific logic. This was accomplished by setting these commands as default values for the config option `autostart.denylisted_rake_tasks`. However, Rails 7 no longer uses Rake for these commands, causing the agent to start running and attempting to record data when running these commands. The commands have now been added to the default value for the config option `autostart.denylisted_constants`, which will allow the agent to recognize these commands correctly in Rails 7 and prevent the agent from starting during ignored tasks. Note that the agent will continue to start up when the `rails server` and `rails runner` commands are invoked. [PR#2239](https://github.com/newrelic/newrelic-ruby-agent/pull/2239)
+
 - **Feature: Enhance Docker container id reporting**
 
   Previously, the agent was only capable of determining a host Docker container's ID if the container was based on cgroups v1. Now, containers based on cgroups v2 will also have their container IDs reported to New Relic. [PR#2229](https://github.com/newrelic/newrelic-ruby-agent/issues/2229).

lib/new_relic/agent/configuration/default_source.rb

@@ -1014,7 +1014,20 @@ def self.enforce_fallback(allowed_values: nil, fallback: nil)
         },
         # Autostart
         :'autostart.denylisted_constants' => {
-          :default => 'Rails::Console',
+          :default => %w[Rails::Command::ConsoleCommand
+            Rails::Command::CredentialsCommand
+            Rails::Command::Db::System::ChangeCommand
+            Rails::Command::DbConsoleCommand
+            Rails::Command::DestroyCommand
+            Rails::Command::DevCommand
+            Rails::Command::EncryptedCommand
+            Rails::Command::GenerateCommand
+            Rails::Command::InitializersCommand
+            Rails::Command::NotesCommand
+            Rails::Command::RoutesCommand
+            Rails::Command::SecretsCommand
+            Rails::Console
+            Rails::DBConsole].join(','),
           :public => true,
           :type => String,
           :allowed_from_server => false,

test/new_relic/agent/autostart_test.rb

@@ -10,17 +10,45 @@ def test_typically_the_agent_should_autostart
     assert_predicate ::NewRelic::Agent::Autostart, :agent_should_start?
   end
 
-  if defined?(::Rails)
-    def test_agent_wont_autostart_if_RAILS_CONSOLE_constant_is_defined
-      refute defined?(::Rails::Console), "precondition: Rails::Console shouldn't be defined"
-      Rails.const_set(:Console, Class.new)
-
-      refute_predicate ::NewRelic::Agent::Autostart, :agent_should_start?, "Agent shouldn't autostart in Rails Console session"
-    ensure
-      Rails.send(:remove_const, :Console)
+  def test_agent_will_not_autostart_in_certain_contexts_recognized_by_constants_being_defined
+    rails_is_present = defined?(::Rails)
+    NewRelic::Agent.config[:'autostart.denylisted_constants'].split(/\s*,\s*/).each do |constant|
+      assert_predicate ::NewRelic::Agent::Autostart, :agent_should_start?, 'Agent should autostart by default'
+
+      # For Rails::Command::ConsoleCommand as an example, eval these:
+      #   'module ::Rails; end',
+      #   'module ::Rails::Command; end', and
+      #   'module ::Rails::Command::ConsoleCommand; end'
+      #
+      # If this test is running within a context that already has Rails defined,
+      # the result of `::NewRelic::LanguageSupport.constantize('::Rails')` will
+      # be non-nil and the first `eval` will be skipped.
+      elements = constant.split('::')
+      elements.inject(+'') do |namespace, element|
+        namespace += "::#{element}"
+        eval("module #{namespace}; end") unless ::NewRelic::LanguageSupport.constantize(namespace)
+        namespace
+      end
+
+      refute_predicate ::NewRelic::Agent::Autostart,
+        :agent_should_start?,
+        "Agent shouldn't autostart when the '#{constant}' constant is defined"
+
+      # For Rails::Command::ConsoleCommand as an example, eval these:
+      # "::Rails::Command.send(:remove_const, 'ConsoleCommand'.to_sym)" and
+      # "::Rails.send(:remove_const, 'Command'.to_sym)".
+      #
+      # and then invoke `Object.send(:remove_const, 'Rails'.to_sym)` to
+      # undefine Rails itself. If Rails was already defined before this test
+      # ran, don't invoke the `Object.send` command and leave Rails alone.
+      dupe = constant.dup
+      while dupe =~ /^.+(::.+)$/
+        element = Regexp.last_match(1)
+        dupe.sub!(/#{element}$/, '')
+        eval("::#{dupe}.send(:remove_const, '#{element.sub('::', '')}'.to_sym)")
+      end
+      Object.send(:remove_const, dupe.to_sym) unless dupe == 'Rails' && rails_is_present
     end
-  else
-    puts "Skipping `test_agent_wont_autostart_if_RAILS_CONSOLE_constant_is_defined` in #{File.basename(__FILE__)} because Rails is unavailable" if ENV['VERBOSE_TEST_OUTPUT']
   end
 
   def test_agent_will_autostart_if_global_CONSOLE_constant_is_defined