Create SelfMonitoringDashboardService and add specs

Set the default dashboard for self monitoring project

app/models/project.rb

@@ -2335,6 +2335,10 @@ class Project < ApplicationRecord
     false
   end
 
+  def self_monitoring?
+    Gitlab::CurrentSettings.self_monitoring_project_id == id
+  end
+
   private
 
   def closest_namespace_setting(name)

app/services/metrics/dashboard/self_monitoring_dashboard_service.rb

+# frozen_string_literal: true
+
+# Fetches the self monitoring metrics dashboard and formats the output.
+# Use Gitlab::Metrics::Dashboard::Finder to retrieve dashboards.
+module Metrics
+  module Dashboard
+    class SelfMonitoringDashboardService < ::Metrics::Dashboard::PredefinedDashboardService
+      DASHBOARD_PATH = 'config/prometheus/self_monitoring_default.yml'
+      DASHBOARD_NAME = 'Default'
+
+      SEQUENCE = [
+        STAGES::ProjectMetricsInserter,
+        STAGES::EndpointInserter,
+        STAGES::Sorter
+      ].freeze
+
+      class << self
+        def valid_params?(params)
+          matching_dashboard?(params[:dashboard_path]) || self_monitoring_project?(params)
+        end
+
+        def all_dashboard_paths(_project)
+          [{
+            path: DASHBOARD_PATH,
+            display_name: DASHBOARD_NAME,
+            default: true,
+            system_dashboard: false
+          }]
+        end
+
+        def self_monitoring_project?(params)
+          params[:dashboard_path].nil? && params[:environment]&.project&.self_monitoring?
+        end
+      end
+    end
+  end
+end

changelogs/unreleased/121719-self-monitoring-default.yml

+---
+title: Set default dashboard for self monitoring project
+merge_request: 24814
+author:
+type: added

lib/gitlab/metrics/dashboard/finder.rb

@@ -65,7 +65,7 @@ module Gitlab
           def find_all_paths_from_source(project)
             Gitlab::Metrics::Dashboard::Cache.delete_all!
 
-            system_service.all_dashboard_paths(project)
+            default_dashboard_path(project)
             .+ project_service.all_dashboard_paths(project)
           end
 
@@ -79,6 +79,18 @@ module Gitlab
             ::Metrics::Dashboard::ProjectDashboardService
           end
 
+          def self_monitoring_service
+            ::Metrics::Dashboard::SelfMonitoringDashboardService
+          end
+
+          def default_dashboard_path(project)
+            if project.self_monitoring?
+              self_monitoring_service.all_dashboard_paths(project)
+            else
+              system_service.all_dashboard_paths(project)
+            end
+          end
+
           def service_for(options)
             Gitlab::Metrics::Dashboard::ServiceSelector.call(options)
           end

lib/gitlab/metrics/dashboard/service_selector.rb

@@ -18,6 +18,7 @@ module Gitlab
             ::Metrics::Dashboard::DefaultEmbedService,
             ::Metrics::Dashboard::SystemDashboardService,
             ::Metrics::Dashboard::PodDashboardService,
+            ::Metrics::Dashboard::SelfMonitoringDashboardService,
             ::Metrics::Dashboard::ProjectDashboardService
           ].freeze
 

spec/lib/gitlab/metrics/dashboard/finder_spec.rb

@@ -44,6 +44,12 @@ describe Gitlab::Metrics::Dashboard::Finder, :use_clean_rails_memory_store_cachi
       it_behaves_like 'valid dashboard service response'
     end
 
+    context 'when the self monitoring dashboard is specified' do
+      let(:dashboard_path) { self_monitoring_dashboard_path }
+
+      it_behaves_like 'valid dashboard service response'
+    end
+
     context 'when no dashboard is specified' do
       let(:service_call) { described_class.find(project, user, environment: environment) }
 
@@ -152,5 +158,33 @@ describe Gitlab::Metrics::Dashboard::Finder, :use_clean_rails_memory_store_cachi
         expect(all_dashboard_paths).to contain_exactly(system_dashboard, project_dashboard)
       end
     end
+
+    context 'when the project is self monitoring' do
+      let(:self_monitoring_dashboard) do
+        {
+          path: self_monitoring_dashboard_path,
+          display_name: 'Default',
+          default: true,
+          system_dashboard: false
+        }
+      end
+      let(:dashboard_path) { '.gitlab/dashboards/test.yml' }
+      let(:project) { project_with_dashboard(dashboard_path) }
+
+      before do
+        stub_application_setting(self_monitoring_project_id: project.id)
+      end
+
+      it 'includes self monitoring and project dashboards' do
+        project_dashboard = {
+          path: dashboard_path,
+          display_name: 'test.yml',
+          default: false,
+          system_dashboard: false
+        }
+
+        expect(all_dashboard_paths).to contain_exactly(self_monitoring_dashboard, project_dashboard)
+      end
+    end
   end
 end

spec/lib/gitlab/metrics/dashboard/service_selector_spec.rb

@@ -30,6 +30,12 @@ describe Gitlab::Metrics::Dashboard::ServiceSelector do
       end
     end
 
+    context 'when the path is for the self monitoring dashboard' do
+      let(:arguments) { { dashboard_path: self_monitoring_dashboard_path } }
+
+      it { is_expected.to be Metrics::Dashboard::SelfMonitoringDashboardService }
+    end
+
     context 'when the embedded flag is provided' do
       let(:arguments) { { embedded: true } }
 

spec/models/project_spec.rb

@@ -5592,6 +5592,24 @@ describe Project do
     it { is_expected.to be_falsey }
   end
 
+  describe '#self_monitoring?' do
+    let_it_be(:project) { create(:project) }
+
+    subject { project.self_monitoring? }
+
+    context 'when the project is instance self monitoring' do
+      before do
+        stub_application_setting(self_monitoring_project_id: project.id)
+      end
+
+      it { is_expected.to be true }
+    end
+
+    context 'when the project is not self monitoring' do
+      it { is_expected.to be false }
+    end
+  end
+
   def rugged_config
     rugged_repo(project.repository).config
   end

spec/services/metrics/dashboard/self_monitoring_dashboard_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Metrics::Dashboard::SelfMonitoringDashboardService, :use_clean_rails_memory_store_caching do
+  include MetricsDashboardHelpers
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:project) { create(:project) }
+  let_it_be(:environment) { create(:environment, project: project) }
+
+  before do
+    project.add_maintainer(user)
+    stub_application_setting(self_monitoring_project_id: project.id)
+  end
+
+  describe '#get_dashboard' do
+    let(:service_params) { [project, user, { environment: environment }] }
+    let(:service_call) { described_class.new(*service_params).get_dashboard }
+
+    it_behaves_like 'valid dashboard service response'
+    it_behaves_like 'raises error for users with insufficient permissions'
+    it_behaves_like 'caches the unprocessed dashboard for subsequent calls'
+  end
+
+  describe '.all_dashboard_paths' do
+    it 'returns the dashboard attributes' do
+      all_dashboards = described_class.all_dashboard_paths(project)
+
+      expect(all_dashboards).to eq(
+        [{
+          path: described_class::DASHBOARD_PATH,
+          display_name: described_class::DASHBOARD_NAME,
+          default: true,
+          system_dashboard: false
+        }]
+      )
+    end
+  end
+
+  describe '.valid_params?' do
+    subject { described_class.valid_params?(params) }
+
+    context 'with environment' do
+      let(:params) { { environment: environment } }
+
+      it { is_expected.to be_truthy }
+    end
+
+    context 'with dashboard_path' do
+      let(:params) { { dashboard_path: self_monitoring_dashboard_path } }
+
+      it { is_expected.to be_truthy }
+    end
+
+    context 'with a different dashboard selected' do
+      let(:dashboard_path) { '.gitlab/dashboards/test.yml' }
+      let(:params) { { dashboard_path: dashboard_path, environment: environment } }
+
+      it { is_expected.to be_falsey }
+    end
+
+    context 'missing environment and dashboard_path' do
+      let(:params) { {} }
+
+      it { is_expected.to be_falsey }
+    end
+  end
+end

spec/support/helpers/metrics_dashboard_helpers.rb

@@ -29,4 +29,8 @@ module MetricsDashboardHelpers
   def business_metric_title
     PrometheusMetricEnums.group_details[:business][:group_title]
   end
+
+  def self_monitoring_dashboard_path
+    Metrics::Dashboard::SelfMonitoringDashboardService::DASHBOARD_PATH
+  end
 end