Add embedding flag and filter to CPU/Mem

This commits adds support for metrics dashboards
for embedding. If the flag 'embedded' is provided
to the environments/id/metrics_dashboard endpoint,
the response will be suitable for embedding in
issues or other content.

This is a precursor for support for embedding
metrics in GFM.

app/controllers/projects/environments_controller.rb

@@ -162,9 +162,17 @@ class Projects::EnvironmentsController < Projects::ApplicationController
     return render_403 unless Feature.enabled?(:environment_metrics_use_prometheus_endpoint, project)
 
     if Feature.enabled?(:environment_metrics_show_multiple_dashboards, project)
-      result = dashboard_finder.find(project, current_user, environment, params[:dashboard])
+      result = dashboard_finder.find(
+        project,
+        current_user,
+        environment,
+        dashboard_path: params[:dashboard],
+        embedded: params[:embedded]
+      )
 
+      unless params[:embedded]
         result[:all_dashboards] = dashboard_finder.find_all_paths(project)
+      end
     else
       result = dashboard_finder.find(project, current_user, environment)
     end

lib/gitlab/metrics/dashboard/base_service.rb

@@ -23,6 +23,11 @@ module Gitlab
           raise NotImplementedError
         end
 
+        # Returns an un-processed dashboard from the cache.
+        def raw_dashboard
+          Gitlab::Metrics::Dashboard::Cache.fetch(cache_key) { get_raw_dashboard }
+        end
+
         private
 
         # Returns a new dashboard Hash, supplemented with DB info
@@ -37,11 +42,6 @@ module Gitlab
           params[:dashboard_path]
         end
 
-        # Returns an un-processed dashboard from the cache.
-        def raw_dashboard
-          Gitlab::Metrics::Dashboard::Cache.fetch(cache_key) { get_raw_dashboard }
-        end
-
         # @return [Hash] an unmodified dashboard
         def get_raw_dashboard
           raise NotImplementedError
@@ -54,6 +54,7 @@ module Gitlab
 
         # Determines whether custom metrics should be included
         # in the processed output.
+        # @return [Boolean]
         def insert_project_metrics?
           false
         end

lib/gitlab/metrics/dashboard/dynamic_dashboard_service.rb

@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+# Responsible for returning a filtered system dashboard
+# containing only the default embedded metrics. In future,
+# this class may be updated to support filtering to
+# alternate metrics/panels.
+#
+# Why isn't this filtering in a processing stage? By filtering
+# here, we ensure the dynamically-determined dashboard is cached.
+#
+# Use Gitlab::Metrics::Dashboard::Finder to retrive dashboards.
+module Gitlab
+  module Metrics
+    module Dashboard
+      class DynamicDashboardService < Gitlab::Metrics::Dashboard::BaseService
+        # For the default filtering for embedded metrics,
+        # uses the 'id' key in dashboard-yml definition for
+        # identification.
+        DEFAULT_EMBEDDED_METRICS_IDENTIFIERS = %w(
+          system_metrics_kubernetes_container_memory_total
+          system_metrics_kubernetes_container_cores_total
+        ).freeze
+
+        # Returns a new dashboard with only the matching
+        # metrics from the system dashboard, stripped of groups.
+        # @return [Hash]
+        def raw_dashboard
+          panels = panel_groups.each_with_object([]) do |group, panels|
+            matched_panels = group['panels'].select { |panel| matching_panel?(panel) }
+
+            panels.concat(matched_panels)
+          end
+
+          { 'panel_groups' => [{ 'panels' => panels }] }
+        end
+
+        def cache_key
+          "dynamic_metrics_dashboard_#{metric_identifiers.join('_')}"
+        end
+
+        private
+
+        # Returns an array of the panels groups on the
+        # system dashboard
+        def panel_groups
+          Gitlab::Metrics::Dashboard::SystemDashboardService
+            .new(project, nil)
+            .raw_dashboard['panel_groups']
+        end
+
+        # Identifies a panel as "matching" if any metric ids in
+        # the panel is in the list of identifiers to collect.
+        def matching_panel?(panel)
+          panel['metrics'].any? do |metric|
+            metric_identifiers.include?(metric['id'])
+          end
+        end
+
+        def metric_identifiers
+          DEFAULT_EMBEDDED_METRICS_IDENTIFIERS
+        end
+      end
+    end
+  end
+end

lib/gitlab/metrics/dashboard/finder.rb

@@ -9,17 +9,28 @@ module Gitlab
       class Finder
         class << self
           # Returns a formatted dashboard packed with DB info.
+          # @param project [Project]
+          # @param user [User]
+          # @param environment [Environment]
+          # @param opts - dashboard_path [String] Path at which the
+          #         dashboard can be found. Nil values will
+          #         default to the system dashboard.
+          # @param opts - embedded [Boolean] Determines whether the
+          #         dashboard is to be rendered as part of an
+          #         issue or location other than the primary
+          #         metrics dashboard UI. Returns only the
+          #         Memory/CPU charts of the system dash.
           # @return [Hash]
-          def find(project, user, environment, dashboard_path = nil)
+          def find(project, user, environment, dashboard_path: nil, embedded: false)
-            service = system_dashboard?(dashboard_path) ? system_service : project_service
+            service_for_path(dashboard_path, embedded: embedded)
-
-            service
               .new(project, user, environment: environment, dashboard_path: dashboard_path)
               .get_dashboard
           end
 
           # Summary of all known dashboards.
-          # @return [Array<Hash>] ex) [{ path: String, default: Boolean }]
+          # @return [Array<Hash>] ex) [{ path: String,
+          #                              display_name: String,
+          #                              default: Boolean }]
           def find_all_paths(project)
             project.repository.metrics_dashboard_paths
           end
@@ -35,6 +46,13 @@ module Gitlab
 
           private
 
+          def service_for_path(dashboard_path, embedded:)
+            return dynamic_service if embedded
+            return system_service if system_dashboard?(dashboard_path)
+
+            project_service
+          end
+
           def system_service
             Gitlab::Metrics::Dashboard::SystemDashboardService
           end
@@ -43,6 +61,10 @@ module Gitlab
             Gitlab::Metrics::Dashboard::ProjectDashboardService
           end
 
+          def dynamic_service
+            Gitlab::Metrics::Dashboard::DynamicDashboardService
+          end
+
           def system_dashboard?(filepath)
             !filepath || system_service.system_dashboard?(filepath)
           end

spec/controllers/projects/environments_controller_spec.rb

@@ -556,6 +556,19 @@ describe Projects::EnvironmentsController do
           it_behaves_like 'has all dashboards'
         end
       end
+
+      context 'when the dashboard is intended for embedding' do
+        let(:dashboard_params) { { format: :json, embedded: true } }
+
+        it_behaves_like '200 response'
+
+        context 'when a dashboard path is provided' do
+          let(:dashboard_params) { { format: :json, dashboard: '.gitlab/dashboards/test.yml', embedded: true } }
+
+          # The dashboard path should simple be ignored.
+          it_behaves_like '200 response'
+        end
+      end
     end
   end
 

spec/fixtures/lib/gitlab/metrics/dashboard/schemas/embedded_dashboard.json

@@ -0,0 +1,13 @@
+{
+  "type": "object",
+  "required": ["panel_groups"],
+  "properties": {
+    "panel_groups": {
+      "type": "array",
+      "items": {
+        "$ref": "spec/fixtures/lib/gitlab/metrics/dashboard/schemas/embedded_panel_groups.json"
+      }
+    }
+  },
+  "additionalProperties": false
+}

spec/fixtures/lib/gitlab/metrics/dashboard/schemas/embedded_panel_groups.json

@@ -0,0 +1,11 @@
+{
+  "type": "object",
+  "required": ["panels"],
+  "properties": {
+    "panels": {
+      "type": "array",
+      "items": { "$ref": "panels.json" }
+    }
+  },
+  "additionalProperties": false
+}

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

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Metrics::Dashboard::DynamicDashboardService, :use_clean_rails_memory_store_caching do
+  include MetricsDashboardHelpers
+
+  set(:project) { build(:project) }
+  set(:environment) { create(:environment, project: project) }
+
+  describe '#get_dashboard' do
+    let(:service_params) { [project, nil, { environment: environment, dashboard_path: nil }] }
+    let(:service_call) { described_class.new(*service_params).get_dashboard }
+
+    it_behaves_like 'valid embedded dashboard service response'
+
+    it 'caches the unprocessed dashboard for subsequent calls' do
+      expect(YAML).to receive(:safe_load).once.and_call_original
+
+      described_class.new(*service_params).get_dashboard
+      described_class.new(*service_params).get_dashboard
+    end
+
+    context 'when called with a non-system dashboard' do
+      let(:dashboard_path) { 'garbage/dashboard/path' }
+
+      it_behaves_like 'valid embedded dashboard service response'
+    end
+  end
+end

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

@@ -11,7 +11,7 @@ describe Gitlab::Metrics::Dashboard::Finder, :use_clean_rails_memory_store_cachi
 
   describe '.find' do
     let(:dashboard_path) { '.gitlab/dashboards/test.yml' }
-    let(:service_call) { described_class.find(project, nil, environment, dashboard_path) }
+    let(:service_call) { described_class.find(project, nil, environment, dashboard_path: dashboard_path) }
 
     it_behaves_like 'misconfigured dashboard service response', :not_found
 
@@ -45,6 +45,12 @@ describe Gitlab::Metrics::Dashboard::Finder, :use_clean_rails_memory_store_cachi
 
       it_behaves_like 'valid dashboard service response'
     end
+
+    context 'when the dashboard is expected to be embedded' do
+      let(:service_call) { described_class.find(project, nil, environment, dashboard_path: nil, embedded: true) }
+
+      it_behaves_like 'valid embedded dashboard service response'
+    end
   end
 
   describe '.find_all_paths' do

spec/support/helpers/metrics_dashboard_helpers.rb

@@ -28,9 +28,7 @@ module MetricsDashboardHelpers
     end
   end
 
-  shared_examples_for 'valid dashboard service response' do
+  shared_examples_for 'valid dashboard service response for schema' do
-    let(:dashboard_schema) { JSON.parse(fixture_file('lib/gitlab/metrics/dashboard/schemas/dashboard.json')) }
-
     it 'returns a json representation of the dashboard' do
       result = service_call
 
@@ -40,4 +38,16 @@ module MetricsDashboardHelpers
       expect(JSON::Validator.fully_validate(dashboard_schema, result[:dashboard])).to be_empty
     end
   end
+
+  shared_examples_for 'valid dashboard service response' do
+    let(:dashboard_schema) { JSON.parse(fixture_file('lib/gitlab/metrics/dashboard/schemas/dashboard.json')) }
+
+    it_behaves_like 'valid dashboard service response for schema'
+  end
+
+  shared_examples_for 'valid embedded dashboard service response' do
+    let(:dashboard_schema) { JSON.parse(fixture_file('lib/gitlab/metrics/dashboard/schemas/embedded_dashboard.json')) }
+
+    it_behaves_like 'valid dashboard service response for schema'
+  end
 end