Always display environment selector

On the metrics dashboard, always display the environment selector,
even if there is no data to display for that environment. This allows
the user to switch to the metrics dashboard of another environment.

app/assets/javascripts/monitoring/components/dashboard.vue

@@ -234,7 +234,7 @@ export default {
 </script>
 
 <template>
-  <div v-if="!showEmptyState" class="prometheus-graphs">
+  <div class="prometheus-graphs">
     <div class="gl-p-3 border-bottom bg-gray-light d-flex justify-content-between">
       <div
         v-if="environmentsEndpoint"
@@ -253,11 +253,12 @@ export default {
               :key="environment.id"
               :active="environment.name === currentEnvironmentName"
               active-class="is-active"
+              :href="environment.metrics_path"
               >{{ environment.name }}</gl-dropdown-item
             >
           </gl-dropdown>
         </div>
-        <div class="d-flex align-items-center prepend-left-8">
+        <div v-if="!showEmptyState" class="d-flex align-items-center prepend-left-8">
           <strong>{{ s__('Metrics|Show last') }}</strong>
           <gl-dropdown
             class="prepend-left-10 js-time-window-dropdown"
@@ -276,7 +277,7 @@ export default {
         </div>
       </div>
       <div class="d-flex">
-        <div v-if="isEE && canAddMetrics">
+        <div v-if="isEE && canAddMetrics && !showEmptyState">
           <gl-button
             v-gl-modal-directive="$options.addMetric.modalId"
             class="js-add-metric-button text-success border-success"
@@ -317,6 +318,7 @@ export default {
         </gl-button>
       </div>
     </div>
+    <div v-if="!showEmptyState">
       <graph-group
         v-for="(groupData, index) in groupsWithData"
         :key="index"
@@ -353,4 +355,5 @@ export default {
       :empty-no-data-svg-path="emptyNoDataSvgPath"
       :empty-unable-to-connect-svg-path="emptyUnableToConnectSvgPath"
     />
+  </div>
 </template>

changelogs/unreleased/always-display-environment-selector.yml

+---
+title: Fix broken environment selector and always display it on monitoring dashboard
+merge_request: 29705
+author:
+type: fixed

spec/features/projects/environments/environment_metrics_spec.rb

@@ -9,11 +9,11 @@ describe 'Environment > Metrics' do
   let(:build) { create(:ci_build, pipeline: pipeline) }
   let(:environment) { create(:environment, project: project) }
   let(:current_time) { Time.now.utc }
+  let!(:staging) { create(:environment, name: 'staging', project: project) }
 
   before do
     project.add_developer(user)
-    create(:deployment, environment: environment, deployable: build)
-    stub_all_prometheus_requests(environment.slug)
+    stub_any_prometheus_request
 
     sign_in(user)
     visit_environment(environment)
@@ -23,15 +23,50 @@ describe 'Environment > Metrics' do
     Timecop.freeze(current_time) { example.run }
   end
 
+  shared_examples 'has environment selector' do
+    it 'has a working environment selector', :js do
+      click_link('See metrics')
+
+      expect(page).to have_metrics_path(environment)
+      expect(page).to have_css('div.js-environments-dropdown')
+
+      within('div.js-environments-dropdown') do
+        # Click on the dropdown
+        click_on(environment.name)
+
+        # Select the staging environment
+        click_on(staging.name)
+      end
+
+      expect(page).to have_metrics_path(staging)
+
+      wait_for_requests
+    end
+  end
+
+  context 'without deployments' do
+    it_behaves_like 'has environment selector'
+  end
+
   context 'with deployments and related deployable present' do
+    before do
+      create(:deployment, environment: environment, deployable: build)
+    end
+
     it 'shows metrics' do
       click_link('See metrics')
 
       expect(page).to have_css('div#prometheus-graphs')
     end
+
+    it_behaves_like 'has environment selector'
   end
 
   def visit_environment(environment)
     visit project_environment_path(environment.project, environment)
   end
+
+  def have_metrics_path(environment)
+    have_current_path(metrics_project_environment_path(project, id: environment.id))
+  end
 end

spec/javascripts/monitoring/dashboard_spec.js

@@ -62,16 +62,34 @@ describe('Dashboard', () => {
   });
 
   describe('no metrics are available yet', () => {
-    it('shows a getting started empty state when no metrics are present', () => {
+    beforeEach(() => {
       component = new DashboardComponent({
         el: document.querySelector('.prometheus-graphs'),
         propsData: { ...propsData },
         store,
       });
+    });
 
+    it('shows a getting started empty state when no metrics are present', () => {
       expect(component.$el.querySelector('.prometheus-graphs')).toBe(null);
       expect(component.emptyState).toEqual('gettingStarted');
     });
+
+    it('shows the environment selector', () => {
+      expect(component.$el.querySelector('.js-environments-dropdown')).toBeTruthy();
+    });
+  });
+
+  describe('no data found', () => {
+    it('shows the environment selector dropdown', () => {
+      component = new DashboardComponent({
+        el: document.querySelector('.prometheus-graphs'),
+        propsData: { ...propsData, showEmptyState: true },
+        store,
+      });
+
+      expect(component.$el.querySelector('.js-environments-dropdown')).toBeTruthy();
+    });
   });
 
   describe('requests information to the server', () => {
@@ -150,14 +168,24 @@ describe('Dashboard', () => {
         singleGroupResponse,
       );
 
-      setTimeout(() => {
+      Vue.nextTick()
+        .then(() => {
           const dropdownMenuEnvironments = component.$el.querySelectorAll(
             '.js-environments-dropdown .dropdown-item',
           );
 
+          expect(component.environments.length).toEqual(environmentData.length);
           expect(dropdownMenuEnvironments.length).toEqual(component.environments.length);
-        done();
+
+          Array.from(dropdownMenuEnvironments).forEach((value, index) => {
+            if (environmentData[index].metrics_path) {
+              expect(value).toHaveAttr('href', environmentData[index].metrics_path);
+            }
           });
+
+          done();
+        })
+        .catch(done.fail);
     });
 
     it('hides the environments dropdown list when there is no environments', done => {
@@ -212,7 +240,7 @@ describe('Dashboard', () => {
       Vue.nextTick()
         .then(() => {
           const dropdownItems = component.$el.querySelectorAll(
-            '.js-environments-dropdown .dropdown-item[active="true"]',
+            '.js-environments-dropdown .dropdown-item.is-active',
           );
 
           expect(dropdownItems.length).toEqual(1);

spec/support/helpers/prometheus_helpers.rb

@@ -70,6 +70,10 @@ module PrometheusHelpers
     WebMock.stub_request(:get, url).to_raise(exception_type)
   end
 
+  def stub_any_prometheus_request
+    WebMock.stub_request(:any, /prometheus.example.com/)
+  end
+
   def stub_all_prometheus_requests(environment_slug, body: nil, status: 200)
     stub_prometheus_request(
       prometheus_query_with_time_url(prometheus_memory_query(environment_slug), Time.now.utc),