Add latest changes from gitlab-org/gitlab@master

1 files changed, 88 insertions, 0 deletions

diff --git a/app/services/prometheus/create_default_alerts_service.rb b/app/services/prometheus/create_default_alerts_service.rb
new file mode 100644
index 00000000000..3eb5ad7711a
--- /dev/null
+++ b/app/services/prometheus/create_default_alerts_service.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+module Prometheus
+  class CreateDefaultAlertsService < BaseService
+    include Gitlab::Utils::StrongMemoize
+
+    attr_reader :project
+
+    DEFAULT_ALERTS = [
+      {
+        identifier: 'response_metrics_nginx_ingress_16_http_error_rate',
+        operator: 'gt',
+        threshold: 0.1
+      },
+      {
+        identifier: 'response_metrics_nginx_ingress_http_error_rate',
+        operator: 'gt',
+        threshold: 0.1
+      }
+    ].freeze
+
+    def initialize(project:)
+      @project = project
+    end
+
+    def execute
+      return ServiceResponse.error(message: 'Invalid project') unless project
+      return ServiceResponse.error(message: 'Invalid environment') unless environment
+
+      create_alerts
+
+      ServiceResponse.success
+    end
+
+    private
+
+    def create_alerts
+      DEFAULT_ALERTS.each do |alert_hash|
+        identifier = alert_hash[:identifier]
+        next if alerts_by_identifier(environment).key?(identifier)
+
+        metric = metrics_by_identifier[identifier]
+        next unless metric
+
+        create_alert(alert: alert_hash, metric: metric)
+      end
+    end
+
+    def metrics_by_identifier
+      strong_memoize(:metrics_by_identifier) do
+        metric_identifiers = DEFAULT_ALERTS.map { |alert| alert[:identifier] }
+
+        PrometheusMetricsFinder
+          .new(identifier: metric_identifiers, common: true)
+          .execute
+          .index_by(&:identifier)
+      end
+    end
+
+    def alerts_by_identifier(environment)
+      strong_memoize(:alerts_by_identifier) do
+        Projects::Prometheus::AlertsFinder
+          .new(project: project, metric: metrics_by_identifier.values, environment: environment)
+          .execute
+          .index_by { |alert| alert.prometheus_metric.identifier }
+      end
+    end
+
+    def environment
+      strong_memoize(:environment) do
+        EnvironmentsFinder.new(project, nil, name: 'production').find.first ||
+          project.environments.first
+      end
+    end
+
+    def create_alert(alert:, metric:)
+      PrometheusAlert.create!(
+        project: project,
+        prometheus_metric: metric,
+        environment: environment,
+        threshold: alert[:threshold],
+        operator: alert[:operator]
+      )
+    rescue ActiveRecord::RecordNotUnique
+      # Ignore duplicate creations although it unlikely to happen
+    end
+  end
+end