Fix code and tests after merge. Fix route

app/models/project_services/prometheus_service.rb

@@ -120,10 +120,10 @@ class PrometheusService < MonitoringService
       Gitlab::PrometheusClient.new(RestClient::Resource.new(api_url))
     else
       cluster = cluster_with_prometheus(environment_id)
-      raise Gitlab::PrometheusError, "couldn't find cluster with Prometheus installed" unless cluster
+      raise Gitlab::PrometheusClient::Error, "couldn't find cluster with Prometheus installed" unless cluster
 
       rest_client = client_from_cluster(cluster)
-      raise Gitlab::PrometheusError, "couldn't create proxy Prometheus client" unless rest_client
+      raise Gitlab::PrometheusClient::Error, "couldn't create proxy Prometheus client" unless rest_client
 
       Gitlab::PrometheusClient.new(rest_client)
     end

config/routes/project.rb

@@ -74,7 +74,7 @@ constraints(ProjectUrlConstrainer.new) do
       resource :mattermost, only: [:new, :create]
 
       namespace :prometheus do
-        resources :metrics, constraints: { id: %r{/[^\/]+} }, only: [:index, :new, :create, :edit, :update, :destroy] do
+        resources :metrics, constraints: { id: %r{[^\/]+} }, only: [:index, :new, :create, :edit, :update, :destroy] do
           post :validate_query, on: :collection
           get :active_common, on: :collection
         end

lib/gitlab/prometheus_client.rb

@@ -75,7 +75,8 @@ module Gitlab
       if response.code == 200 && response['status'] == 'success'
         response['data'] || {}
       elsif response.code == 400
-        raise PrometheusClient::QueryError, response['error'] || 'Bad data received'
+        json_data = JSON.parse(response.body)
+        raise PrometheusClient::QueryError, json_data['error'] || 'Bad data received'
       else
         raise PrometheusClient::Error, "#{response.code} - #{response.body}"
       end

spec/lib/gitlab/prometheus_client_spec.rb

@@ -23,7 +23,7 @@ describe Gitlab::PrometheusClient do
         req_stub = stub_prometheus_request(query_url, status: 400, body: { error: 'bar!' })
 
         expect { execute_query }
-          .to raise_error(Gitlab::PrometheusClient::Error, 'bar!')
+          .to raise_error(Gitlab::PrometheusClient::QueryError, 'bar!')
         expect(req_stub).to have_been_requested
       end
     end
@@ -33,7 +33,7 @@ describe Gitlab::PrometheusClient do
         req_stub = stub_prometheus_request(query_url, status: 400)
 
         expect { execute_query }
-          .to raise_error(Gitlab::PrometheusClient::Error, 'Bad data received')
+          .to raise_error(Gitlab::PrometheusClient::QueryError, 'Bad data received')
         expect(req_stub).to have_been_requested
       end
     end
@@ -49,11 +49,11 @@ describe Gitlab::PrometheusClient do
     end
 
     context 'when request returns non json data' do
-      it 'raises a Gitlab::PrometheusError error' do
+      it 'raises a Gitlab::PrometheusClient::Error error' do
         req_stub = stub_prometheus_request(query_url, status: 200, body: 'not json')
 
         expect { execute_query }
-          .to raise_error(Gitlab::PrometheusError, 'Parsing response failed')
+          .to raise_error(Gitlab::PrometheusClient::Error, 'Parsing response failed')
         expect(req_stub).to have_been_requested
       end
     end

spec/models/project_services/prometheus_service_spec.rb

@@ -246,8 +246,8 @@ describe PrometheusService, :use_clean_rails_memory_store_caching do
 
       context 'with cluster for all environments without prometheus installed' do
         context 'without environment supplied' do
-          it 'raises PrometheusError because cluster was not found' do
-            expect { service.client }.to raise_error(Gitlab::PrometheusError, /couldn't find cluster with Prometheus installed/)
+          it 'raises PrometheusClient::Error because cluster was not found' do
+            expect { service.client }.to raise_error(Gitlab::PrometheusClient::Error, /couldn't find cluster with Prometheus installed/)
           end
         end
 
@@ -265,8 +265,8 @@ describe PrometheusService, :use_clean_rails_memory_store_caching do
         context 'with prod environment supplied' do
           let!(:environment) { create(:environment, project: project, name: 'prod') }
 
-          it 'raises PrometheusError because cluster was not found' do
-            expect { service.client }.to raise_error(Gitlab::PrometheusError, /couldn't find cluster with Prometheus installed/)
+          it 'raises PrometheusClient::Error because cluster was not found' do
+            expect { service.client }.to raise_error(Gitlab::PrometheusClient::Error, /couldn't find cluster with Prometheus installed/)
           end
         end
       end