Resolve "Alert notification not working for managed Prometheus installations"

ee/app/services/clusters/applications/prometheus_config_service.rb

@@ -3,9 +3,10 @@
 module Clusters
   module Applications
     class PrometheusConfigService
-      def initialize(project, cluster)
+      def initialize(project, cluster, app)
         @project = project
         @cluster = cluster
+        @app = app
       end
 
       def execute(config)
@@ -18,7 +19,7 @@ module Clusters
 
       private
 
-      attr_reader :project, :cluster
+      attr_reader :project, :cluster, :app
 
       def reset_alert_manager(config)
         config = set_alert_manager_enabled(config, false)
@@ -80,13 +81,22 @@ module Clusters
             'webhook_configs' => [
               {
                 'url' => notify_url,
-                'send_resolved' => true
+                'send_resolved' => true,
+                'http_config' => {
+                  'bearer_token' => alert_manager_token
+                }
               }
             ]
           }
         ]
       end
 
+      def alert_manager_token
+        app.generate_alert_manager_token!
+
+        app.alert_manager_token
+      end
+
       def alert_manager_route_params
         {
           'receiver' => 'gitlab',
@@ -97,11 +107,8 @@ module Clusters
       end
 
       def notify_url
-        ::Gitlab::Routing.url_helpers.notify_namespace_project_prometheus_alerts_url(
-          namespace_id: project.namespace.path,
-          project_id: project.path,
-          format: :json
-        )
+        ::Gitlab::Routing.url_helpers
+          .notify_project_prometheus_alerts_url(project, format: :json)
       end
 
       def has_alerts?

ee/app/services/clusters/applications/prometheus_update_service.rb

@@ -34,7 +34,7 @@ module Clusters
 
       def update_config(config)
         PrometheusConfigService
-          .new(project, cluster)
+          .new(project, cluster, app)
           .execute(config)
       end
     end

ee/changelogs/unreleased/9558-alert-notification-not-working-for-managed-prometheus-installations.yml

+---
+title: Fix alert notifications for managed Prometheus
+merge_request: 9402
+author:
+type: fixed

ee/spec/services/clusters/applications/prometheus_config_service_spec.rb

@@ -3,11 +3,17 @@
 require 'spec_helper'
 
 describe Clusters::Applications::PrometheusConfigService do
+  include Gitlab::Routing.url_helpers
+
   set(:project) { create(:project) }
   set(:production) { create(:environment, project: project) }
   set(:cluster) { create(:cluster, :provided_by_user, projects: [project]) }
 
-  subject { described_class.new(project, cluster).execute(input) }
+  let(:application) do
+    create(:clusters_applications_prometheus, :installed, cluster: cluster)
+  end
+
+  subject { described_class.new(project, cluster, application).execute(input) }
 
   describe '#execute' do
     let(:input) do
@@ -37,7 +43,7 @@ describe Clusters::Applications::PrometheusConfigService do
           let(:webhook_config) { receiver.dig('webhook_configs', 0) }
 
           let(:notify_url) do
-            "http://localhost/#{project.namespace.name}/#{project.name}/prometheus/alerts/notify.json"
+            notify_project_prometheus_alerts_url(project, format: :json)
           end
 
           it 'sets receiver' do
@@ -47,7 +53,10 @@ describe Clusters::Applications::PrometheusConfigService do
           it 'sets webhook_config' do
             expect(webhook_config).to eq(
               'url' => notify_url,
-              'send_resolved' => true
+              'send_resolved' => true,
+              'http_config' => {
+                'bearer_token' => application.alert_manager_token
+              }
             )
           end
         end

ee/spec/services/clusters/applications/prometheus_update_service_spec.rb

@@ -42,7 +42,7 @@ describe Clusters::Applications::PrometheusUpdateService do
 
         expect(Clusters::Applications::PrometheusConfigService)
           .to receive(:new)
-          .with(project, cluster)
+          .with(project, cluster, application)
           .and_return(prometheus_config_service)
 
         expect(prometheus_config_service)