Merge branch 'fix-kube_client-proxy_url-exception' into 'master'

Rescue Kubeclient::HttpError when generating prometheus_client

See merge request gitlab-org/gitlab-ce!18989

app/models/clusters/applications/prometheus.rb

@@ -49,6 +49,11 @@ module Clusters
         # ensures headers containing auth data are appended to original k8s client options
         options = kube_client.rest_client.options.merge(headers: kube_client.headers)
         RestClient::Resource.new(proxy_url, options)
+      rescue Kubeclient::HttpError
+        # If users have mistakenly set parameters or removed the depended clusters,
+        # `proxy_url` could raise an exception because gitlab can not communicate with the cluster.
+        # Since `PrometheusAdapter#can_query?` is eargely loaded on environement pages in gitlab,
+        # we need to silence the exceptions
       end
 
       private

changelogs/unreleased/fix-kube_client-proxy_url-exception.yml

+---
+title: Fix corrupted environment pages with unathorized proxy url
+merge_request: 18989
+author:
+type: fixed

spec/features/projects/environments/environments_spec.rb

@@ -42,6 +42,22 @@ feature 'Environments page', :js do
           expect(page).to have_content('You don\'t have any environments right now')
         end
       end
+
+      context 'when cluster is not reachable' do
+        let!(:cluster) { create(:cluster, :provided_by_gcp, projects: [project]) }
+        let!(:application_prometheus) { create(:clusters_applications_prometheus, :installed, cluster: cluster) }
+
+        before do
+          allow_any_instance_of(Kubeclient::Client).to receive(:proxy_url).and_raise(Kubeclient::HttpError.new(401, 'Unauthorized', nil))
+        end
+
+        it 'should show one environment without error' do
+          visit_environments(project, scope: 'available')
+
+          expect(page).to have_css('.environments-container')
+          expect(page.all('.environment-name').length).to eq(1)
+        end
+      end
     end
 
     describe 'with one stopped environment' do

spec/models/clusters/applications/prometheus_spec.rb

@@ -85,6 +85,16 @@ describe Clusters::Applications::Prometheus do
       it 'copies options and headers from kube client to proxy client' do
         expect(subject.prometheus_client.options).to eq(kube_client.rest_client.options.merge(headers: kube_client.headers))
       end
+
+      context 'when cluster is not reachable' do
+        before do
+          allow(kube_client).to receive(:proxy_url).and_raise(Kubeclient::HttpError.new(401, 'Unauthorized', nil))
+        end
+
+        it 'returns nil' do
+          expect(subject.prometheus_client).to be_nil
+        end
+      end
     end
   end