Merge pull request #39 from bigcommerce/INFRA-25589-metrics-scrape-content-type

INFRA-25589: fix(metrics) Add version=0.0.4 to Content-Type for Prometheus exposition format 0.0.4 compliance

Author: bc-dhruvin

CHANGELOG.md

@@ -2,6 +2,10 @@ Changelog for the bc-prometheus-ruby gem.
 
 ### Pending Release
 
+## 0.8.2
+
+- Add `version=0.0.4` to `Content-Type` header for Prometheus exposition format 0.0.4 compliance
+
 ## 0.8.1
 
 - Prometheus client respects the enabled setting

lib/bigcommerce/prometheus/servers/puma/controllers/metrics_controller.rb

@@ -39,7 +39,7 @@ def call
                 @response.write(collected_metrics)
               end
 
-              set_header('Content-Type', 'text/plain; charset=utf-8')
+              set_header('Content-Type', 'text/plain; version=0.0.4; charset=utf-8')
               @response
             end
 

lib/bigcommerce/prometheus/version.rb

@@ -17,6 +17,6 @@
 #
 module Bigcommerce
   module Prometheus
-    VERSION = '0.8.2.pre'
+    VERSION = '0.8.2'
   end
 end

spec/bigcommerce/prometheus/servers/puma/controllers/metrics_controller_spec.rb

@@ -49,6 +49,10 @@
 ruby_collector_sessions_total 19'
     end
 
+    it 'sets Prometheus text format 0.0.4 content type' do
+      expect(subject.headers['Content-Type']).to eq('text/plain; version=0.0.4; charset=utf-8')
+    end
+
     context 'when the metrics fail to parse' do
       let(:timeout_exception) { ::Timeout::Error }
       before do

spec/bigcommerce/prometheus/servers/puma/rack_app_spec.rb

@@ -41,9 +41,9 @@
         }
       end
 
-      it 'returns content type of text/plain' do
+      it 'returns Prometheus text format 0.0.4 content type' do
         _status, headers, _body = subject
-        expect(headers['Content-Type']).to eq('text/plain; charset=utf-8')
+        expect(headers['Content-Type']).to eq('text/plain; version=0.0.4; charset=utf-8')
       end
     end