[im-2290] Instrument timeout exceptions (#110)

* instrument timeout exceptions

.gitignore

@@ -1,3 +1,5 @@
+.vscode
+.idea
 .bundle/
 doc/
 .yardoc/

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 _A description of your awesome changes here!_
 
+- Instrument timeout exceptions (#110)
+
 ### 3.7.1
 
 Features:

lib/routemaster/middleware/metrics.rb

@@ -22,6 +22,9 @@ def call(request_env)
           rescue Routemaster::Errors::BaseError => e
             increment_response_count(response_tags(e.env))
             raise e
+          rescue Faraday::TimeoutError => e
+            increment_response_count(%W[source:#{source_peer} destination:#{request_env.url.host} status:timeout])
+            raise e
           end
         end
       end

spec/routemaster/integration/api_client_spec.rb

@@ -394,5 +394,32 @@ def timestamp ; subject.get(url).body.updated_at ; end
         'api_client.latency', tags: %w[source:test_service destination:127.0.0.1 verb:get]
       )
     end
+
+    context 'when the response status code is non-2xx' do
+      it 'sends the response metrics with the status code and error class fatal resource' do
+        expect { subject.post("#{host}/429") }.to raise_error(Routemaster::Errors::ResourceThrottling)
+
+        expect(metrics_client).to have_received(:increment).with(
+          'api_client.response.count', tags: %w[source:test_service destination:127.0.0.1 status:429]
+        )
+      end
+
+      it 'sends the response metrics with the status code and error class fatal resource' do
+        expect { subject.post("#{host}/500") }.to raise_error(Routemaster::Errors::FatalResource)
+
+        expect(metrics_client).to have_received(:increment).with(
+          'api_client.response.count', tags: %w[source:test_service destination:127.0.0.1 status:500]
+        )
+      end
+
+      it 'sends the response metrics with the status code and error class fatal resource' do
+        stub_request(:put, "#{host}/429").to_timeout
+        expect { subject.put("#{host}/429") }.to raise_error(Faraday::TimeoutError)
+
+        expect(metrics_client).to have_received(:increment).with(
+          'api_client.response.count', tags: %w[source:test_service destination:127.0.0.1 status:timeout]
+        ).at_least(1).times
+      end
+    end
   end
 end