Add changes from code review around comments and add test for the new environment variable.

Author: wantsui

lib/datadog/core/configuration/settings.rb

@@ -1003,7 +1003,7 @@ def initialize(*_)
           end
         end
 
-        # Enable experimental process tags propagation.
+        # Enable experimental process tags propagation such that payloads like spans contain the process tag.
         #
         # @default `DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED` environment variable, otherwise `false`
         # @return [Boolean]

lib/datadog/core/environment/ext.rb

@@ -33,7 +33,7 @@ module Ext
         LANG_INTERPRETER = "#{RUBY_ENGINE}-#{RUBY_PLATFORM}"
         LANG_PLATFORM = RUBY_PLATFORM
         LANG_VERSION = RUBY_VERSION
-        PROCESS_TYPE = 'script'
+        PROCESS_TYPE = 'script' # Out of the options [jar, script, class, executable], we consider Ruby to always be a script
         RUBY_ENGINE = ::RUBY_ENGINE # e.g. 'ruby', 'jruby', 'truffleruby'
         TAG_ENV = 'env'
         TAG_ENTRYPOINT_BASEDIR = "entrypoint.basedir"

lib/datadog/core/environment/process.rb

@@ -6,36 +6,48 @@
 module Datadog
   module Core
     module Environment
-      # Retrieves process level information
+      # Retrieves process level information such that it can be attached to various payloads
       module Process
         module_function
 
+        # Returns the last segment of the working directory of the process
+        # @return [String] the last segment of the working directory
         def entrypoint_workdir
           File.basename(Dir.pwd)
         end
 
+        # Returns the entrypoint type of the process
+        # @return [String] the type of the process, which is fixed in Ruby
         def entrypoint_type
           Core::Environment::Ext::PROCESS_TYPE
         end
 
+        # Returns the last segment of the base directory of the process
+        # @return [String] the last segment of base directory of the script
         def entrypoint_name
           File.basename($0)
         end
 
+        # Returns the last segment of the base directory of the process
+        # @return [String] the last segment of the base directory of the script
         def entrypoint_basedir
           current_basedir = File.expand_path(File.dirname($0))
           normalized_basedir = current_basedir.tr(File::SEPARATOR, '/')
           normalized_basedir.delete_prefix!('/')
         end
 
-        # Normalize tag key and value using the Datadog Agent's tag normalization logic
+        # Normalize tag key and value using the Trace Agent's tag normalization logic
+        # @param key [String] the original key
+        # @param value [String] the original value
+        # @return [String] normalized key:value pair
         def serialized_kv_helper(key, value)
           key = Core::Normalizer.normalize(key)
           value = Core::Normalizer.normalize(value)
           "#{key}:#{value}"
         end
 
         # This method returns a key/value part of serialized tags in the format of k1:v1,k2:v2,k3:v3
+        # @return [String] comma-separated normalized key:value pairs
         def serialized
           return @serialized if defined?(@serialized)
           tags = []

spec/datadog/core/configuration/settings_spec.rb

@@ -1337,6 +1337,45 @@
     end
   end
 
+    describe '#experimental_propagate_process_tags_enabled' do
+    subject(:experimental_propagate_process_tags_enabled) { settings.experimental_propagate_process_tags_enabled }
+
+    context "when #{Datadog::Core::Environment::Ext::ENV_VERSION}" do
+      around do |example|
+        ClimateControl.modify('DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED' => environment) do
+          example.run
+        end
+      end
+
+      context 'by default' do
+        let(:environment) { nil }
+
+        it { is_expected.to be false }
+      end
+
+      context 'when set to true' do
+        let(:environment) { 'true' }
+
+        it { is_expected.to be true }
+      end
+
+      context 'when set to false' do
+        let(:environment) { 'false' }
+
+        it { is_expected.to be false }
+      end
+    end
+  end
+
+  describe '#experimental_propagate_process_tags_enabled=' do
+    it 'updates the #experimental_propagate_process_tags_enabled setting' do
+      expect { settings.experimental_propagate_process_tags_enabled = true }
+        .to change { settings.experimental_propagate_process_tags_enabled }
+        .from(false)
+        .to(true)
+    end
+  end
+
   describe '#time_now_provider=' do
     subject(:set_time_now_provider) { settings.time_now_provider = time_now_provider }