Update user agent info to match spec (#1182)

* Update user agent info to match spec

* Add changelog entry

CHANGELOG.asciidoc

@@ -40,6 +40,7 @@ endif::[]
 
 - Fixed span context fields for DynamoDB instrumentation {pull}1178[#1178]
 - Fixed span context fields for S3 instrumentation {pull}1179[#1179]
+- Update user agent info to match spec {pull}1182[#1182]
 
 [[release-notes-4.4.0]]
 ==== 4.4.0

lib/elastic_apm/metadata/service_info.rb

@@ -49,7 +49,7 @@ def initialize(config)
         )
         @language = Language.new(name: 'ruby', version: RUBY_VERSION)
         @runtime = lookup_runtime
-        @version = @config.service_version || Util.git_sha
+        @version = @config.service_version
       end
 
       attr_reader :name, :node_name, :environment, :agent, :framework,

lib/elastic_apm/transport/user_agent.rb

@@ -37,12 +37,18 @@ def build(config)
 
         [
           "elastic-apm-ruby/#{@version}",
-          HTTP::Request::USER_AGENT,
-          [
-            service.runtime.name,
-            service.runtime.version
-          ].join('/')
-        ].join(' ')
+          formatted_service_info(service)
+        ].compact.join(' ')
+      end
+
+      def formatted_service_info(service)
+        if service.name
+          "(#{[
+                service.name,
+                service.version
+               ].compact.join(' ')
+             })"
+        end
       end
     end
   end

spec/elastic_apm/metadata/service_info_spec.rb

@@ -43,10 +43,6 @@ module ElasticAPM
         expect(subject.runtime.name).to eq 'jruby'
         expect(subject.runtime.version).to_not be_nil
       end
-
-      it 'has a version from git' do
-        expect(subject.version).to match(/[a-z0-9]{16}/) # git sha
-      end
     end
   end
 end

spec/elastic_apm/transport/connection_spec.rb

@@ -80,9 +80,7 @@ module Transport
           headers: {
             'User-Agent' =>
               %r{
-                \Aelastic-apm-ruby/(\d+\.)+\d([a-z0-9\.]+)?+\s
-                http.rb/(\d+\.)+\d+\s
-                j?ruby/(\d+\.)+\d+\z
+                \Aelastic-apm-ruby/(\d+\.)+\d([a-z0-9\.]+)?+
               }x
           }
         )

spec/elastic_apm/transport/user_agent_spec.rb

@@ -22,24 +22,56 @@
 module ElasticAPM
   module Transport
     RSpec.describe UserAgent do
-      REGEXP =
-        %r{
-          \Aelastic-apm-ruby/(\d+\.)+\d([a-z0-9\.]+)?+\s
-          http.rb/(\d+\.)+\d+\s
-          j?ruby/(\d+\.)+\d+\z
-        }x
-
-      let(:config) { Config.new }
       subject { described_class.new(config) }
 
-      describe 'to_s' do
+      context 'when there is no service name or version' do
+        let(:regexp) do
+          %r{
+            \Aelastic-apm-ruby\/(\d+\.)+\d([a-z0-9\.]+)?+
+          }x
+        end
+
+        let(:config) { Config.new }
+
         it 'builds a string' do
-          expect(subject.to_s).to match(REGEXP)
+          expect(subject.to_s).to match(regexp)
         end
 
         it 'handles beta versions' do
           subject = described_class.new(config, version: '12.13.14.beta.20')
-          expect(subject.to_s).to match(REGEXP)
+          expect(subject.to_s).to match(regexp)
+        end
+      end
+
+      context 'when there is service name only' do
+        let(:regexp) do
+          %r{
+            \Aelastic-apm-ruby/(\d+\.)+\d([a-z0-9\.]+)?+\s
+            \(MyService\)
+          }x
+        end
+
+        let(:config) { Config.new(service_name: "MyService") }
+
+        it 'builds a string' do
+          expect(subject.to_s).to match(regexp)
+        end
+      end
+
+      context 'when there is service name and version' do
+        let(:regexp) do
+          %r{
+            \Aelastic-apm-ruby\/(\d+\.)+\d([a-z0-9\.]+)?+\s
+            \(MyService\sv42\)
+          }x
+        end
+
+        let(:config) do
+          Config.new(service_name: "MyService", service_version: 'v42')
+        end
+
+        it 'builds a string' do
+          expect(subject.to_s).to match(regexp)
         end
       end
     end