Falcon instrumentation

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## v9.7.0
 
-Version 9.7.0 changes the endpoint used to access the cluster name for Elasticsearch instrumentation.
+Version 9.7.0 changes the endpoint used to access the cluster name for Elasticsearch instrumentation and adds support for Falcon.
 
 - **Feature: Use root path to access Elasticsearch cluster name**
 
@@ -18,6 +18,10 @@ Version 9.7.0 changes the endpoint used to access the cluster name for Elasticse
 
   Thank you, [@Earlopain](https://github.com/Earlopain), for submitting this change. [PR#2378](https://github.com/newrelic/newrelic-ruby-agent/pull/2378)
 
+- **Feature: Add Falcon support**
+
+  The agent now supports the web server [Falcon](https://socketry.github.io/falcon/). [PR#2383](https://github.com/newrelic/newrelic-ruby-agent/pull/2383)
+
 ## v9.6.0
 
 Version 9.6.0 adds instrumentation for Async::HTTP, Ethon, and HTTPX, adds the ability to ignore specific routes with Roda, gleans Docker container IDs from cgroups v2-based containers, records additional synthetics attributes, fixes an issue with Rails 7.1 that could cause duplicate log records to be sent to New Relic, fixes a deprecation warning for the Sidekiq error handler, adds additional attributes for OpenTelemetry compatibility, and resolves some technical debt, thanks to the community.

lib/new_relic/agent/agent_helpers/special_startup.rb

@@ -10,7 +10,7 @@ module SpecialStartup
         # requests, we need to wait until the children are forked
         # before connecting, otherwise the parent process sends useless data
         def using_forking_dispatcher?
-          if [:puma, :passenger, :unicorn].include?(Agent.config[:dispatcher])
+          if [:puma, :passenger, :unicorn, :falcon].include?(Agent.config[:dispatcher])
             ::NewRelic::Agent.logger.info('Deferring startup of agent reporting thread because ' \
               "#{Agent.config[:dispatcher]} may fork.")
             true

lib/new_relic/local_environment.rb

@@ -74,6 +74,7 @@ def discover_dispatcher
         unicorn
         webrick
         fastcgi
+        falcon
       ]
       while dispatchers.any? && @discovered_dispatcher.nil?
         send('check_for_' + (dispatchers.shift))
@@ -138,6 +139,12 @@ def check_for_puma
       end
     end
 
+    def check_for_falcon
+      if defined?(::Falcon::Server) && NewRelic::LanguageSupport.object_space_usable?
+        @discovered_dispatcher = :falcon if find_class_in_object_space(::Falcon::Server)
+      end
+    end
+
     def check_for_delayed_job
       if $0 =~ /delayed_job$/ || (File.basename($0) == 'rake' && ARGV.include?('jobs:work'))
         @discovered_dispatcher = :delayed_job