[CLIENT] Meta header: Adds service version

Author: picandocodigo

elasticsearch-transport/lib/elasticsearch/transport/client.rb

@@ -209,8 +209,10 @@ def add_header(header)
       def set_meta_header
         return if @arguments[:enable_meta_header] == false
 
+        service, version = meta_header_service_version
+
         meta_headers = {
-          es: Elasticsearch::VERSION, # TODO - es|ent
+          service.to_sym => version,
           rb: RUBY_VERSION,
           t: Elasticsearch::Transport::VERSION
         }
@@ -220,6 +222,16 @@ def set_meta_header
         add_header({ 'x-elastic-client-meta' => meta_headers.map { |k, v| "#{k}=#{v}" }.join(',') })
       end
 
+      def meta_header_service_version
+        if defined?(Elastic::META_HEADER_SERVICE_VERSION)
+          Elastic::META_HEADER_SERVICE_VERSION
+        elsif defined?(Elasticsearch::VERSION)
+          ['es', Elasticsearch::VERSION]
+        else
+          ['es', Elasticsearch::Transport::VERSION]
+        end
+      end
+
       def meta_header_engine
         case RUBY_ENGINE
         when 'ruby'

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

@@ -178,5 +178,26 @@ def initialize(args); end
         expect(subject).to include('x-elastic-client-meta' => meta_header)
       end
     end
+
+    context 'when using a different service version' do
+      before do
+        module Elastic
+          META_HEADER_SERVICE_VERSION = [:ent, '8.0.0']
+        end
+      end
+
+      after do
+        module Elastic
+          META_HEADER_SERVICE_VERSION = [:es, Elasticsearch::VERSION]
+        end
+      end
+
+      let(:client) { Elasticsearch::Client.new }
+
+      it 'sets the service version in the metaheader' do
+        expect(subject['x-elastic-client-meta']).to match(regexp)
+        expect(subject['x-elastic-client-meta']).to start_with('ent=8.0.0')
+      end
+    end
   end
 end

elasticsearch/lib/elasticsearch.rb

@@ -27,3 +27,7 @@ class Client
     end
   end
 end
+module Elastic
+  # Constant for elasticsearch-transport meta-header
+  META_HEADER_SERVICE_VERSION = [:es, Elasticsearch::VERSION]
+end

elasticsearch/test/integration/client_integration_test.rb

@@ -70,6 +70,10 @@ class ClientIntegrationTest < Elasticsearch::Test::IntegrationTestCase
           end
         end
 
+        should 'report the right meta header' do
+          headers = @client.transport.connections.first.connection.headers
+          assert_match /^es=#{Elasticsearch::VERSION}/, headers['x-elastic-client-meta']
+        end
       end
     end
   end