Add Metrics Dasboard graphQL resource

In order to allow quering metrics dashboard data for each of
environents we need to add new graphQL entities.

app/graphql/resolvers/metrics/dashboard_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  module Metrics
+    class DashboardResolver < Resolvers::BaseResolver
+      argument :path, GraphQL::STRING_TYPE,
+               required: true,
+               description: "Path to a file which defines metrics dashboard eg: 'config/prometheus/common_metrics.yml'"
+
+      type Types::Metrics::DashboardType, null: true
+
+      alias_method :environment, :object
+
+      def resolve(**args)
+        return unless environment
+
+        ::PerformanceMonitoring::PrometheusDashboard.find_for(project: environment.project, user: context[:current_user], path: args[:path], options: { environment: environment })
+      end
+    end
+  end
+end

app/graphql/types/environment_type.rb

@@ -15,5 +15,9 @@ module Types
 
     field :state, GraphQL::STRING_TYPE, null: false,
           description: 'State of the environment, for example: available/stopped'
+
+    field :metrics_dashboard, Types::Metrics::DashboardType, null: true,
+          description: 'Metrics dashboard schema for the environment',
+          resolver: Resolvers::Metrics::DashboardResolver
   end
 end

app/graphql/types/metrics/dashboard_type.rb

+# frozen_string_literal: true
+
+module Types
+  module Metrics
+    # rubocop: disable Graphql/AuthorizeTypes
+    # Authorization is performed at environment level
+    class DashboardType < ::Types::BaseObject
+      graphql_name 'MetricsDashboard'
+
+      field :path, GraphQL::STRING_TYPE, null: true,
+            description: 'Path to a file with the dashboard definition'
+    end
+    # rubocop: enable Graphql/AuthorizeTypes
+  end
+end

doc/api/graphql/reference/gitlab_schema.graphql

@@ -1865,6 +1865,16 @@ type Environment {
   """
   id: ID!
 
+  """
+  Metrics dashboard schema for the environment
+  """
+  metricsDashboard(
+    """
+    Path to a file which defines metrics dashboard eg: 'config/prometheus/common_metrics.yml'
+    """
+    path: String!
+  ): MetricsDashboard
+
   """
   Human-readable name of the environment
   """
@@ -5147,6 +5157,13 @@ type Metadata {
   version: String!
 }
 
+type MetricsDashboard {
+  """
+  Path to a file with the dashboard definition
+  """
+  path: String
+}
+
 """
 Represents a milestone.
 """

doc/api/graphql/reference/gitlab_schema.json

@@ -5525,6 +5525,33 @@
               "isDeprecated": false,
               "deprecationReason": null
             },
+            {
+              "name": "metricsDashboard",
+              "description": "Metrics dashboard schema for the environment",
+              "args": [
+                {
+                  "name": "path",
+                  "description": "Path to a file which defines metrics dashboard eg: 'config/prometheus/common_metrics.yml'",
+                  "type": {
+                    "kind": "NON_NULL",
+                    "name": null,
+                    "ofType": {
+                      "kind": "SCALAR",
+                      "name": "String",
+                      "ofType": null
+                    }
+                  },
+                  "defaultValue": null
+                }
+              ],
+              "type": {
+                "kind": "OBJECT",
+                "name": "MetricsDashboard",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "name",
               "description": "Human-readable name of the environment",
@@ -14729,6 +14756,33 @@
           "enumValues": null,
           "possibleTypes": null
         },
+        {
+          "kind": "OBJECT",
+          "name": "MetricsDashboard",
+          "description": null,
+          "fields": [
+            {
+              "name": "path",
+              "description": "Path to a file with the dashboard definition",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "SCALAR",
+                "name": "String",
+                "ofType": null
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            }
+          ],
+          "inputFields": null,
+          "interfaces": [
+
+          ],
+          "enumValues": null,
+          "possibleTypes": null
+        },
         {
           "kind": "OBJECT",
           "name": "Milestone",

doc/api/graphql/reference/index.md

@@ -317,6 +317,7 @@ Describes where code is deployed for a project
 | Name  | Type  | Description |
 | ---   |  ---- | ----------  |
 | `id` | ID! | ID of the environment |
+| `metricsDashboard` | MetricsDashboard | Metrics dashboard schema for the environment |
 | `name` | String! | Human-readable name of the environment |
 | `state` | String! | State of the environment, for example: available/stopped |
 
@@ -781,6 +782,12 @@ Autogenerated return type of MergeRequestSetWip
 | `revision` | String! | Revision |
 | `version` | String! | Version |
 
+## MetricsDashboard
+
+| Name  | Type  | Description |
+| ---   |  ---- | ----------  |
+| `path` | String | Path to a file with the dashboard definition |
+
 ## Milestone
 
 Represents a milestone.

spec/graphql/resolvers/metrics/dashboard_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Resolvers::Metrics::DashboardResolver do
+  include GraphqlHelpers
+
+  let_it_be(:current_user) { create(:user) }
+
+  describe '#resolve' do
+    subject(:resolve_dashboard) { resolve(described_class, obj: parent_object, args: args, ctx: { current_user: current_user }) }
+
+    let(:args) do
+      {
+        path: 'config/prometheus/common_metrics.yml'
+      }
+    end
+
+    context 'for environment' do
+      let(:project) { create(:project) }
+      let(:parent_object) { create(:environment, project: project) }
+
+      before do
+        project.add_developer(current_user)
+      end
+
+      it 'use ActiveModel class to find matching dashboard', :aggregate_failures do
+        expected_arguments = { project: project, user: current_user, path: args[:path], options: { environment: parent_object } }
+
+        expect(PerformanceMonitoring::PrometheusDashboard).to receive(:find_for).with(expected_arguments).and_return(PerformanceMonitoring::PrometheusDashboard.new)
+        expect(resolve_dashboard).to be_instance_of PerformanceMonitoring::PrometheusDashboard
+      end
+
+      context 'without parent object' do
+        let(:parent_object) { nil }
+
+        it 'returns nil', :aggregate_failures do
+          expect(PerformanceMonitoring::PrometheusDashboard).not_to receive(:find_for)
+          expect(resolve_dashboard).to be_nil
+        end
+      end
+    end
+  end
+end

spec/graphql/types/environment_type_spec.rb

@@ -7,7 +7,7 @@ describe GitlabSchema.types['Environment'] do
 
   it 'has the expected fields' do
     expected_fields = %w[
-      name id state
+      name id state metrics_dashboard
     ]
 
     expect(described_class).to have_graphql_fields(*expected_fields)

spec/graphql/types/metrics/dashboard_type_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe GitlabSchema.types['MetricsDashboard'] do
+  it { expect(described_class.graphql_name).to eq('MetricsDashboard') }
+
+  it 'has the expected fields' do
+    expected_fields = %w[
+      path
+    ]
+
+    expect(described_class).to have_graphql_fields(*expected_fields)
+  end
+end

spec/requests/api/graphql/metrics/dashboard_query_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'Getting Metrics Dashboard' do
+  include GraphqlHelpers
+
+  let_it_be(:current_user) { create(:user) }
+  let(:project) { create(:project) }
+  let!(:environment) { create(:environment, project: project) }
+
+  let(:fields) do
+    <<~QUERY
+      #{all_graphql_fields_for('MetricsDashboard'.classify)}
+    QUERY
+  end
+
+  let(:query) do
+    %(
+      query {
+        project(fullPath:"#{project.full_path}") {
+          environments(name: "#{environment.name}") {
+            nodes {
+              metricsDashboard(path: "#{path}"){
+                #{fields}
+              }
+            }
+          }
+        }
+      }
+    )
+  end
+
+  context 'for anonymous user' do
+    before do
+      post_graphql(query, current_user: current_user)
+    end
+
+    context 'requested dashboard is available' do
+      let(:path) { 'config/prometheus/common_metrics.yml' }
+
+      it_behaves_like 'a working graphql query'
+
+      it 'returns nil' do
+        dashboard = graphql_data.dig('project', 'environments', 'nodes')
+
+        expect(dashboard).to be_nil
+      end
+    end
+  end
+
+  context 'for user with developer access' do
+    before do
+      project.add_developer(current_user)
+      post_graphql(query, current_user: current_user)
+    end
+
+    context 'requested dashboard is available' do
+      let(:path) { 'config/prometheus/common_metrics.yml' }
+
+      it_behaves_like 'a working graphql query'
+
+      it 'returns metrics dashboard' do
+        dashboard = graphql_data.dig('project', 'environments', 'nodes')[0]['metricsDashboard']
+
+        expect(dashboard).to eql("path" => path)
+      end
+    end
+
+    context 'requested dashboard can not be found' do
+      let(:path) { 'config/prometheus/i_am_not_here.yml' }
+
+      it_behaves_like 'a working graphql query'
+
+      it 'return snil' do
+        dashboard = graphql_data.dig('project', 'environments', 'nodes')[0]['metricsDashboard']
+
+        expect(dashboard).to be_nil
+      end
+    end
+  end
+end