[CLIENT] Refactors meta header to support using other Elastic clients in same project

Author: picandocodigo

elasticsearch-transport/lib/elasticsearch/transport/meta_header.rb

@@ -41,15 +41,31 @@ def set_meta_header
       end
 
       def meta_header_service_version
-        if defined?(Elastic::META_HEADER_SERVICE_VERSION)
-          Elastic::META_HEADER_SERVICE_VERSION
+        if enterprise_search?
+          Elastic::ENTERPRISE_SERVICE_VERSION
+        elsif elasticsearch?
+          Elastic::ELASTICSEARCH_SERVICE_VERSION
         elsif defined?(Elasticsearch::VERSION)
           [:es, client_meta_version(Elasticsearch::VERSION)]
         else
           [:es, client_meta_version(Elasticsearch::Transport::VERSION)]
         end
       end
 
+      def enterprise_search?
+        defined?(Elastic::ENTERPRISE_SERVICE_VERSION) &&
+          called_from?('enterprise-search-ruby')
+      end
+
+      def elasticsearch?
+        defined?(Elastic::ELASTICSEARCH_SERVICE_VERSION) &&
+          called_from?('elasticsearch')
+      end
+
+      def called_from?(service)
+        !caller.select { |c| c.match?(service) }.empty?
+      end
+
       # We return the current version if it's a release, but if it's a pre/alpha/beta release we
       # return <VERSION_NUMBER>p
       #

elasticsearch-transport/spec/elasticsearch/transport/meta_header_spec.rb

@@ -251,7 +251,7 @@ def initialize(args); end
 
     context 'when using a different service version' do
       before do
-        stub_const("Elastic::META_HEADER_SERVICE_VERSION", [:ent, '8.0.0'])
+        stub_const('Elastic::ELASTICSEARCH_SERVICE_VERSION', [:ent, '8.0.0'])
       end
 
       let(:client) { Elasticsearch::Client.new }

elasticsearch/lib/elasticsearch.rb

@@ -38,5 +38,5 @@ def self.client_meta_version
   end
 
   # Constant for elasticsearch-transport meta-header
-  META_HEADER_SERVICE_VERSION = [:es, client_meta_version].freeze
+  ELASTICSEARCH_SERVICE_VERSION = [:es, client_meta_version].freeze
 end