Add latest changes from gitlab-org/gitlab@master

1 files changed, 85 insertions, 0 deletions

diff --git a/app/services/clusters/applications/prometheus_health_check_service.rb b/app/services/clusters/applications/prometheus_health_check_service.rb
new file mode 100644
index 00000000000..e609d9f0b7b
--- /dev/null
+++ b/app/services/clusters/applications/prometheus_health_check_service.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+module Clusters
+  module Applications
+    class PrometheusHealthCheckService
+      include Gitlab::Utils::StrongMemoize
+      include Gitlab::Routing
+
+      def initialize(cluster)
+        @cluster = cluster
+        @logger = Gitlab::AppJsonLogger.build
+      end
+
+      def execute
+        raise 'Invalid cluster type. Only project types are allowed.' unless @cluster.project_type?
+
+        return unless prometheus_application.installed?
+
+        project = @cluster.clusterable
+
+        @logger.info(
+          message: 'Prometheus health check',
+          cluster_id: @cluster.id,
+          newly_unhealthy: became_unhealthy?,
+          currently_healthy: currently_healthy?,
+          was_healthy: was_healthy?
+        )
+
+        send_notification(project) if became_unhealthy?
+
+        prometheus_application.update_columns(healthy: currently_healthy?) if health_changed?
+      end
+
+      private
+
+      def prometheus_application
+        strong_memoize(:prometheus_application) do
+          @cluster.application_prometheus
+        end
+      end
+
+      def currently_healthy?
+        strong_memoize(:currently_healthy) do
+          prometheus_application.prometheus_client.healthy?
+        end
+      end
+
+      def became_unhealthy?
+        strong_memoize(:became_unhealthy) do
+          (was_healthy? || was_healthy?.nil?) && !currently_healthy?
+        end
+      end
+
+      def was_healthy?
+        strong_memoize(:was_healthy) do
+          prometheus_application.healthy
+        end
+      end
+
+      def health_changed?
+        was_healthy? != currently_healthy?
+      end
+
+      def send_notification(project)
+        notification_payload = build_notification_payload(project)
+        token = project.alerts_service.data.token
+        Projects::Alerting::NotifyService.new(project, nil, notification_payload).execute(token)
+        @logger.info(message: 'Successfully notified of Prometheus newly unhealthy', cluster_id: @cluster.id, project_id: project.id)
+      end
+
+      def build_notification_payload(project)
+        cluster_path = namespace_project_cluster_path(
+          project_id: project.path,
+          namespace_id: project.namespace.path,
+          id: @cluster.id
+        )
+
+        {
+          title: "Prometheus is Unhealthy. Cluster Name: #{@cluster.name}",
+          description: "Prometheus is unhealthy for the cluster: [#{@cluster.name}](#{cluster_path}) attached to project #{project.name}."
+        }
+      end
+    end
+  end
+end