This adds a status label to http_requests_total

This adds a status label to the http_requests_total metric. To do so,
we've had to move the recording to an ensure block after the request
is performed.

In practise our @app.call never fails. But there's a spec covering the
recording of the request count even if it fails. That's why the
recording happens inside an ensure.

lib/gitlab/metrics/requests_rack_middleware.rb

@@ -49,14 +49,9 @@ module Gitlab
         method = 'INVALID' unless HTTP_METHODS.key?(method)
         started = Time.now.to_f
         health_endpoint = health_endpoint?(env['PATH_INFO'])
+        status = 'undefined'
 
         begin
-          if health_endpoint
-            RequestsRackMiddleware.http_health_requests_total.increment(method: method)
-          else
-            RequestsRackMiddleware.http_request_total.increment(method: method)
-          end
-
           status, headers, body = @app.call(env)
 
           elapsed = Time.now.to_f - started
@@ -69,6 +64,12 @@ module Gitlab
         rescue
           RequestsRackMiddleware.rack_uncaught_errors_count.increment
           raise
+        ensure
+          if health_endpoint
+            RequestsRackMiddleware.http_health_requests_total.increment(method: method, status: status)
+          else
+            RequestsRackMiddleware.http_request_total.increment(method: method, status: status)
+          end
         end
       end
 

spec/lib/gitlab/metrics/requests_rack_middleware_spec.rb

@@ -22,7 +22,7 @@ RSpec.describe Gitlab::Metrics::RequestsRackMiddleware do
       end
 
       it 'increments requests count' do
-        expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get')
+        expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get', status: 200)
 
         subject.call(env)
       end
@@ -45,7 +45,7 @@ RSpec.describe Gitlab::Metrics::RequestsRackMiddleware do
             end
 
             it 'increments health endpoint counter rather than overall counter' do
-              expect(described_class).to receive_message_chain(:http_health_requests_total, :increment).with(method: 'get')
+              expect(described_class).to receive_message_chain(:http_health_requests_total, :increment).with(method: 'get', status: 200)
               expect(described_class).not_to receive(:http_request_total)
 
               subject.call(env)
@@ -68,7 +68,7 @@ RSpec.describe Gitlab::Metrics::RequestsRackMiddleware do
             end
 
             it 'increments overall counter rather than health endpoint counter' do
-              expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get')
+              expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get', status: 200)
               expect(described_class).not_to receive(:http_health_requests_total)
 
               subject.call(env)
@@ -101,7 +101,7 @@ RSpec.describe Gitlab::Metrics::RequestsRackMiddleware do
       end
 
       it 'increments requests count' do
-        expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get')
+        expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get', status: 'undefined')
 
         expect { subject.call(env) }.to raise_error(StandardError)
       end