Adds support for Grafana dashboard urls in GFM

Adds filters for supporting the ability to embed Grafana metrics
in GitLab Flavored Markdown. Adds a filter which identifies
references in GFM to the domain corresponding to a configured
GrafanaIntegration for the project.

Note: This is only available for Prometheus datasources which are
configured to be proxied through Grafana.

app/controllers/concerns/metrics_dashboard.rb

@@ -3,21 +3,24 @@
 # Provides an action which fetches a metrics dashboard according
 # to the parameters specified by the controller.
 module MetricsDashboard
+  include RenderServiceResults
   extend ActiveSupport::Concern
 
   def metrics_dashboard
     result = dashboard_finder.find(
       project_for_dashboard,
       current_user,
-      metrics_dashboard_params
+      metrics_dashboard_params.to_h.symbolize_keys
     )
 
-    if include_all_dashboards?
+    if include_all_dashboards? && result
       result[:all_dashboards] = dashboard_finder.find_all_paths(project_for_dashboard)
     end
 
     respond_to do |format|
-      if result[:status] == :success
+      if result.nil?
+        format.json { continue_polling_response }
+      elsif result[:status] == :success
         format.json { render dashboard_success_response(result) }
       else
         format.json { render dashboard_error_response(result) }
@@ -56,7 +59,7 @@ module MetricsDashboard
 
   def dashboard_error_response(result)
     {
-      status: result[:http_status],
+      status: result[:http_status] || :bad_request,
       json: result.slice(:all_dashboards, :message, :status)
     }
   end

app/controllers/projects/environments_controller.rb

@@ -199,8 +199,7 @@ class Projects::EnvironmentsController < Projects::ApplicationController
 
   def metrics_dashboard_params
     params
-      .permit(:embedded, :group, :title, :y_label)
-      .to_h.symbolize_keys
+      .permit(:embedded, :group, :title, :y_label, :dashboard_path, :environment)
       .merge(dashboard_path: params[:dashboard], environment: environment)
   end
 

app/controllers/projects/grafana_api_controller.rb

@@ -2,6 +2,9 @@
 
 class Projects::GrafanaApiController < Projects::ApplicationController
   include RenderServiceResults
+  include MetricsDashboard
+
+  before_action :validate_feature_enabled!, only: [:metrics_dashboard]
 
   def proxy
     result = ::Grafana::ProxyService.new(
@@ -19,6 +22,14 @@ class Projects::GrafanaApiController < Projects::ApplicationController
 
   private
 
+  def metrics_dashboard_params
+    params.permit(:embedded, :grafana_url)
+  end
+
+  def validate_feature_enabled!
+    render_403 unless Feature.enabled?(:gfm_grafana_integration)
+  end
+
   def query_params
     params.permit(:query, :start, :end, :step)
   end

config/routes/project.rb

@@ -187,9 +187,10 @@ constraints(::Constraints::ProjectUrlConstrainer.new) do
         resource :import, only: [:new, :create, :show]
         resource :avatar, only: [:show, :destroy]
 
-        get 'grafana/proxy/:datasource_id/*proxy_path',
-            to: 'grafana_api#proxy',
-            as: :grafana_api
+        scope :grafana, as: :grafana_api do
+          get 'proxy/:datasource_id/*proxy_path', to: 'grafana_api#proxy'
+          get :metrics_dashboard, to: 'grafana_api#metrics_dashboard'
+        end
       end
       # End of the /-/ scope.
 

lib/banzai/filter/inline_grafana_metrics_filter.rb

+# frozen_string_literal: true
+
+module Banzai
+  module Filter
+    # HTML filter that inserts a placeholder element for each
+    # reference to a grafana dashboard.
+    class InlineGrafanaMetricsFilter < Banzai::Filter::InlineEmbedsFilter
+      # Placeholder element for the frontend to use as an
+      # injection point for charts.
+      def create_element(params)
+        begin_loading_dashboard(params[:url])
+
+        doc.document.create_element(
+          'div',
+          class: 'js-render-metrics',
+          'data-dashboard-url': metrics_dashboard_url(params)
+        )
+      end
+
+      def embed_params(node)
+        return unless Feature.enabled?(:gfm_grafana_integration)
+
+        query_params = Gitlab::Metrics::Dashboard::Url.parse_query(node['href'])
+        return unless [:panelId, :from, :to].all? do |param|
+          query_params.include?(param)
+        end
+
+        { url: node['href'], start: query_params[:from], end: query_params[:to] }
+      end
+
+      # Selects any links with an href contains the configured
+      # grafana domain for the project
+      def xpath_search
+        return unless grafana_url.present?
+
+        %(descendant-or-self::a[starts-with(@href, '#{grafana_url}')])
+      end
+
+      private
+
+      def project
+        context[:project]
+      end
+
+      def grafana_url
+        project&.grafana_integration&.grafana_url
+      end
+
+      def metrics_dashboard_url(params)
+        Gitlab::Routing.url_helpers.project_grafana_api_metrics_dashboard_url(
+          project,
+          embedded: true,
+          grafana_url: params[:url],
+          start: format_time(params[:start]),
+          end: format_time(params[:end])
+        )
+      end
+
+      # Formats a timestamp from Grafana for compatibility with
+      # parsing in JS via `new Date(timestamp)`
+      #
+      # @param time [String] Represents miliseconds since epoch
+      def format_time(time)
+        Time.at(time.to_i / 1000).utc.strftime('%FT%TZ')
+      end
+
+      # Fetches a dashboard and caches the result for the
+      # FE to fetch quickly while rendering charts
+      def begin_loading_dashboard(url)
+        ::Gitlab::Metrics::Dashboard::Finder.find(
+          project,
+          embedded: true,
+          grafana_url: url
+        )
+      end
+    end
+  end
+end

lib/banzai/filter/inline_metrics_redactor_filter.rb

@@ -8,14 +8,17 @@ module Banzai
       include Gitlab::Utils::StrongMemoize
 
       METRICS_CSS_CLASS = '.js-render-metrics'
+      URL = Gitlab::Metrics::Dashboard::Url
+
+      Embed = Struct.new(:project_path, :permission)
 
       # Finds all embeds based on the css class the FE
       # uses to identify the embedded content, removing
       # only unnecessary nodes.
       def call
         nodes.each do |node|
-          path = paths_by_node[node]
-          user_has_access = user_access_by_path[path]
+          embed = embeds_by_node[node]
+          user_has_access = user_access_by_embed[embed]
 
           node.remove unless user_has_access
         end
@@ -30,40 +33,69 @@ module Banzai
       end
 
       # Returns all nodes which the FE will identify as
-      # a metrics dashboard placeholder element
+      # a metrics embed placeholder element
       #
       # @return [Nokogiri::XML::NodeSet]
       def nodes
         @nodes ||= doc.css(METRICS_CSS_CLASS)
       end
 
-      # Maps a node to the full path of a project.
+      # Maps a node to key properties of an embed.
       # Memoized so we only need to run the regex to get
       # the project full path from the url once per node.
       #
-      # @return [Hash<Nokogiri::XML::Node, String>]
-      def paths_by_node
-        strong_memoize(:paths_by_node) do
-          nodes.each_with_object({}) do |node, paths|
-            paths[node] = path_for_node(node)
+      # @return [Hash<Nokogiri::XML::Node, Embed>]
+      def embeds_by_node
+        strong_memoize(:embeds_by_node) do
+          nodes.each_with_object({}) do |node, embeds|
+            embed = Embed.new
+            url = node.attribute('data-dashboard-url').to_s
+
+            set_path_and_permission(embed, url, URL.regex, :read_environment)
+            set_path_and_permission(embed, url, URL.grafana_regex, :read_project) unless embed.permission
+
+            embeds[node] = embed if embed.permission
           end
         end
       end
 
-      # Gets a project's full_path from the dashboard url
-      # in the placeholder node. The FE will use the attr
-      # `data-dashboard-url`, so we want to check against that
-      # attribute directly in case a user has manually
-      # created a metrics element (rather than supporting
-      # an alternate attr in InlineMetricsFilter).
+      # Attempts to determine the path and permission attributes
+      # of a url based on expected dashboard url formats and
+      # sets the attributes on an Embed object
       #
-      # @return [String]
-      def path_for_node(node)
-        url = node.attribute('data-dashboard-url').to_s
-
-        Gitlab::Metrics::Dashboard::Url.regex.match(url) do |m|
+      # @param embed [Embed]
+      # @param url [String]
+      # @param regex [RegExp]
+      # @param permission [Symbol]
+      def set_path_and_permission(embed, url, regex, permission)
+        return unless path = regex.match(url) do |m|
           "#{$~[:namespace]}/#{$~[:project]}"
         end
+
+        embed.project_path = path
+        embed.permission = permission
+      end
+
+      # Returns a mapping representing whether the current user
+      # has permission to view the embed for the project.
+      # Determined in a batch
+      #
+      # @return [Hash<Embed, Boolean>]
+      def user_access_by_embed
+        strong_memoize(:user_access_by_embed) do
+          unique_embeds.each_with_object({}) do |embed, access|
+            project = projects_by_path[embed.project_path]
+
+            access[embed] = Ability.allowed?(user, embed.permission, project)
+          end
+        end
+      end
+
+      # Returns a unique list of embeds
+      #
+      # @return [Array<Embed>]
+      def unique_embeds
+        embeds_by_node.values.uniq
       end
 
       # Maps a project's full path to a Project object.
@@ -74,22 +106,17 @@ module Banzai
       def projects_by_path
         strong_memoize(:projects_by_path) do
           Project.eager_load(:route, namespace: [:route])
-            .where_full_path_in(paths_by_node.values.uniq)
+            .where_full_path_in(unique_project_paths)
             .index_by(&:full_path)
         end
       end
 
-      # Returns a mapping representing whether the current user
-      # has permission to view the metrics for the project.
-      # Determined in a batch
+      # Returns a list of the full_paths of every project which
+      # has an embed in the doc
       #
-      # @return [Hash<Project, Boolean>]
-      def user_access_by_path
-        strong_memoize(:user_access_by_path) do
-          projects_by_path.each_with_object({}) do |(path, project), access|
-            access[path] = Ability.allowed?(user, :read_environment, project)
-          end
-        end
+      # @return [Array<String>]
+      def unique_project_paths
+        embeds_by_node.values.map(&:project_path).uniq
       end
     end
   end

lib/banzai/pipeline/gfm_pipeline.rb

@@ -30,6 +30,7 @@ module Banzai
           Filter::ImageLazyLoadFilter,
           Filter::ImageLinkFilter,
           Filter::InlineMetricsFilter,
+          Filter::InlineGrafanaMetricsFilter,
           Filter::TableOfContentsFilter,
           Filter::AutolinkFilter,
           Filter::ExternalLinkFilter,

lib/gitlab/metrics/dashboard/finder.rb

@@ -12,6 +12,7 @@ module Gitlab
           # @param project [Project]
           # @param user [User]
           # @param environment [Environment]
+          # @param options [Hash<Symbol,Any>]
           # @param options - embedded [Boolean] Determines whether the
           #         dashboard is to be rendered as part of an
           #         issue or location other than the primary
@@ -31,6 +32,8 @@ module Gitlab
           # @param options - cluster [Cluster]
           # @param options - cluster_type [Symbol] The level of
           #         cluster, one of [:admin, :project, :group]
+          # @param options - grafana_url [String] URL pointing
+          #         to a grafana dashboard panel
           # @return [Hash]
           def find(project, user, options = {})
             service_for(options)

lib/gitlab/metrics/dashboard/service_selector.rb

@@ -18,6 +18,7 @@ module Gitlab
           # @return [Gitlab::Metrics::Dashboard::Services::BaseService]
           def call(params)
             return SERVICES::CustomMetricEmbedService if custom_metric_embed?(params)
+            return SERVICES::GrafanaMetricEmbedService if grafana_metric_embed?(params)
             return SERVICES::DynamicEmbedService if dynamic_embed?(params)
             return SERVICES::DefaultEmbedService if params[:embedded]
             return SERVICES::SystemDashboardService if system_dashboard?(params[:dashboard_path])
@@ -40,6 +41,10 @@ module Gitlab
             SERVICES::CustomMetricEmbedService.valid_params?(params)
           end
 
+          def grafana_metric_embed?(params)
+            SERVICES::GrafanaMetricEmbedService.valid_params?(params)
+          end
+
           def dynamic_embed?(params)
             SERVICES::DynamicEmbedService.valid_params?(params)
           end

lib/gitlab/metrics/dashboard/url.rb

@@ -14,17 +14,31 @@ module Gitlab
           def regex
             %r{
               (?<url>
-                #{Regexp.escape(Gitlab.config.gitlab.url)}
-                \/#{Project.reference_pattern}
+                #{gitlab_pattern}
+                #{project_pattern}
                 (?:\/\-)?
                 \/environments
                 \/(?<environment>\d+)
                 \/metrics
-                (?<query>
-                  \?[a-zA-Z0-9%.()+_=-]+
-                  (&[a-zA-Z0-9%.()+_=-]+)*
-                )?
-                (?<anchor>\#[a-z0-9_-]+)?
+                #{query_pattern}
+                #{anchor_pattern}
+              )
+            }x
+          end
+
+          # Matches dashboard urls for a Grafana embed.
+          #
+          # EX - https://<host>/<namespace>/<project>/grafana/metrics_dashboard
+          def grafana_regex
+            %r{
+              (?<url>
+                #{gitlab_pattern}
+                #{project_pattern}
+                (?:\/\-)?
+                \/grafana
+                \/metrics_dashboard
+                #{query_pattern}
+                #{anchor_pattern}
               )
             }x
           end
@@ -45,6 +59,24 @@ module Gitlab
           def build_dashboard_url(*args)
             Gitlab::Routing.url_helpers.metrics_dashboard_namespace_project_environment_url(*args)
           end
+
+          private
+
+          def gitlab_pattern
+            Regexp.escape(Gitlab.config.gitlab.url)
+          end
+
+          def project_pattern
+            "\/#{Project.reference_pattern}"
+          end
+
+          def query_pattern
+            '(?<query>\?[a-zA-Z0-9%.()+_=-]+(&[a-zA-Z0-9%.()+_=-]+)*)?'
+          end
+
+          def anchor_pattern
+            '(?<anchor>\#[a-z0-9_-]+)?'
+          end
         end
       end
     end

spec/controllers/concerns/metrics_dashboard_spec.rb

@@ -31,17 +31,28 @@ describe MetricsDashboard do
     end
 
     context 'when params are provided' do
+      let(:params) { { environment: environment } }
+
       before do
         allow(controller).to receive(:project).and_return(project)
         allow(controller)
           .to receive(:metrics_dashboard_params)
-          .and_return(environment: environment)
+          .and_return(params)
+      end
+
+      it 'returns the specified dashboard' do
+        expect(json_response['dashboard']['dashboard']).to eq('Environment metrics')
+        expect(json_response).not_to have_key('all_dashboards')
       end
 
+      context 'when the params are in an alternate format' do
+        let(:params) { ActionController::Parameters.new({ environment: environment }).permit! }
+
         it 'returns the specified dashboard' do
           expect(json_response['dashboard']['dashboard']).to eq('Environment metrics')
           expect(json_response).not_to have_key('all_dashboards')
         end
+      end
 
       context 'when parameters are provided and the list of all dashboards is required' do
         before do

spec/controllers/projects/grafana_api_controller_spec.rb

@@ -94,4 +94,87 @@ describe Projects::GrafanaApiController do
       end
     end
   end
+
+  describe 'GET #metrics_dashboard' do
+    let(:service_result) { { status: :success, dashboard: '{}' } }
+    let(:params) do
+      {
+        format: :json,
+        embedded: true,
+        grafana_url: 'https://grafana.example.com',
+        namespace_id: project.namespace.full_path,
+        project_id: project.name
+      }
+    end
+
+    before do
+      allow(Gitlab::Metrics::Dashboard::Finder)
+      .to receive(:find)
+      .and_return(service_result)
+    end
+
+    context 'when the result is still processing' do
+      let(:service_result) { nil }
+
+      it 'returns 204 no content' do
+        get :metrics_dashboard, params: params
+
+        expect(response).to have_gitlab_http_status(:no_content)
+      end
+    end
+
+    context 'when the result was successful' do
+      it 'returns the dashboard response' do
+        get :metrics_dashboard, params: params
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(json_response).to eq({
+          'dashboard' => '{}',
+          'status' => 'success'
+        })
+      end
+    end
+
+    context 'when an error has occurred' do
+      shared_examples_for 'error response' do |http_status|
+        it "returns #{http_status}" do
+          get :metrics_dashboard, params: params
+
+          expect(response).to have_gitlab_http_status(http_status)
+          expect(json_response['status']).to eq('error')
+          expect(json_response['message']).to eq('error message')
+        end
+      end
+
+      context 'with an error accessing grafana' do
+        let(:service_result) do
+          {
+            http_status: :service_unavailable,
+            status: :error,
+            message: 'error message'
+          }
+        end
+
+        it_behaves_like 'error response', :service_unavailable
+      end
+
+      context 'with a processing error' do
+        let(:service_result) { { status: :error, message: 'error message' } }
+
+        it_behaves_like 'error response', :bad_request
+      end
+    end
+
+    context 'when grafana embeds are not enabled' do
+      before do
+        stub_feature_flags(gfm_grafana_integration: false)
+      end
+
+      it 'returns 403 immediately' do
+        get :metrics_dashboard, params: params
+
+        expect(response).to have_gitlab_http_status(:forbidden)
+      end
+    end
+  end
 end

spec/lib/banzai/filter/inline_grafana_metrics_filter_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Banzai::Filter::InlineGrafanaMetricsFilter do
+  include FilterSpecHelper
+
+  let_it_be(:project) { create(:project) }
+  let_it_be(:grafana_integration) { create(:grafana_integration, project: project) }
+
+  let(:input) { %(<a href="#{url}">example</a>) }
+  let(:doc) { filter(input) }
+
+  let(:url) { grafana_integration.grafana_url + dashboard_path }
+  let(:dashboard_path) do
+    '/d/XDaNK6amz/gitlab-omnibus-redis' \
+    '?from=1570397739557&to=1570484139557' \
+    '&var-instance=All&panelId=14'
+  end
+
+  context 'when feature flag is disabled' do
+    before do
+      stub_feature_flags(gfm_grafana_integration: false)
+    end
+
+    it 'leaves the markdown unchanged' do
+      expect(unescape(doc.to_s)).to eq(input)
+    end
+  end
+
+  it 'appends a metrics charts placeholder with dashboard url after metrics links' do
+    node = doc.at_css('.js-render-metrics')
+    expect(node).to be_present
+
+    dashboard_url = urls.project_grafana_api_metrics_dashboard_url(
+      project,
+      embedded: true,
+      grafana_url: url,
+      start: "2019-10-06T21:35:39Z",
+      end: "2019-10-07T21:35:39Z"
+    )
+
+    expect(node.attribute('data-dashboard-url').to_s).to eq(dashboard_url)
+  end
+
+  context 'when the dashboard link is part of a paragraph' do
+    let(:paragraph) { %(This is an <a href="#{url}">example</a> of metrics.) }
+    let(:input) { %(<p>#{paragraph}</p>) }
+
+    it 'appends the charts placeholder after the enclosing paragraph' do
+      expect(unescape(doc.at_css('p').to_s)).to include(paragraph)
+      expect(doc.at_css('.js-render-metrics')).to be_present
+    end
+  end
+
+  context 'when grafana is not configured' do
+    before do
+      allow(project).to receive(:grafana_integration).and_return(nil)
+    end
+
+    it 'leaves the markdown unchanged' do
+      expect(unescape(doc.to_s)).to eq(input)
+    end
+  end
+
+  context 'when parameters are missing' do
+    let(:dashboard_path) { '/d/XDaNK6amz/gitlab-omnibus-redis' }
+
+    it 'leaves the markdown unchanged' do
+      expect(unescape(doc.to_s)).to eq(input)
+    end
+  end
+
+  private
+
+  # Nokogiri escapes the URLs, but we don't care about that
+  # distinction for the purposes of this filter
+  def unescape(html)
+    CGI.unescapeHTML(html)
+  end
+end

spec/lib/banzai/filter/inline_metrics_redactor_filter_spec.rb

@@ -18,8 +18,7 @@ describe Banzai::Filter::InlineMetricsRedactorFilter do
   end
 
   context 'with a metrics charts placeholder' do
-    let(:input) { %(<div class="js-render-metrics" data-dashboard-url="#{url}"></div>) }
-
+    shared_examples_for 'a supported metrics dashboard url' do
       context 'no user is logged in' do
         it 'redacts the placeholder' do
           expect(doc.to_s).to be_empty
@@ -45,4 +44,23 @@ describe Banzai::Filter::InlineMetricsRedactorFilter do
         end
       end
     end
+
+    let(:input) { %(<div class="js-render-metrics" data-dashboard-url="#{url}"></div>) }
+
+    it_behaves_like 'a supported metrics dashboard url'
+
+    context 'for a grafana dashboard' do
+      let(:url) { urls.project_grafana_api_metrics_dashboard_url(project, embedded: true) }
+
+      it_behaves_like 'a supported metrics dashboard url'
+    end
+
+    context 'for an internal non-dashboard url' do
+      let(:url) { urls.project_url(project) }
+
+      it 'leaves the placeholder' do
+        expect(doc.to_s).to be_empty
+      end
+    end
+  end
 end

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

@@ -75,6 +75,17 @@ describe Gitlab::Metrics::Dashboard::ServiceSelector do
 
         it { is_expected.to be Metrics::Dashboard::CustomMetricEmbedService }
       end
+
+      context 'with a grafana link' do
+        let(:arguments) do
+          {
+            embedded: true,
+            grafana_url: 'https://grafana.example.com'
+          }
+        end
+
+        it { is_expected.to be Metrics::Dashboard::GrafanaMetricEmbedService }
+      end
     end
   end
 end

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

@@ -3,13 +3,41 @@
 require 'spec_helper'
 
 describe Gitlab::Metrics::Dashboard::Url do
-  describe '#regex' do
-    it 'returns a regular expression' do
-      expect(described_class.regex).to be_a Regexp
-    end
+  shared_examples_for 'a regex which matches the expected url' do
+    it { is_expected.to be_a Regexp }
 
     it 'matches a metrics dashboard link with named params' do
-      url = Gitlab::Routing.url_helpers.metrics_namespace_project_environment_url(
+      expect(subject).to match url
+
+      subject.match(url) do |m|
+        expect(m.named_captures).to eq expected_params
+      end
+    end
+  end
+
+  shared_examples_for 'does not match non-matching urls' do
+    it 'does not match other gitlab urls that contain the term metrics' do
+      url = Gitlab::Routing.url_helpers.active_common_namespace_project_prometheus_metrics_url('foo', 'bar', :json)
+
+      expect(subject).not_to match url
+    end
+
+    it 'does not match other gitlab urls' do
+      url = Gitlab.config.gitlab.url
+
+      expect(subject).not_to match url
+    end
+
+    it 'does not match non-gitlab urls' do
+      url = 'https://www.super_awesome_site.com/'
+
+      expect(subject).not_to match url
+    end
+  end
+
+  describe '#regex' do
+    let(:url) do
+      Gitlab::Routing.url_helpers.metrics_namespace_project_environment_url(
         'foo',
         'bar',
         1,
@@ -18,8 +46,10 @@ describe Gitlab::Metrics::Dashboard::Url do
         group: 'awesome group',
         anchor: 'title'
       )
+    end
 
-      expected_params = {
+    let(:expected_params) do
+      {
         'url' => url,
         'namespace' => 'foo',
         'project' => 'bar',
@@ -27,31 +57,40 @@ describe Gitlab::Metrics::Dashboard::Url do
         'query' => '?dashboard=config%2Fprometheus%2Fcommon_metrics.yml&group=awesome+group&start=2019-08-02T05%3A43%3A09.000Z',
         'anchor' => '#title'
       }
-
-      expect(described_class.regex).to match url
-
-      described_class.regex.match(url) do |m|
-        expect(m.named_captures).to eq expected_params
-      end
     end
 
-    it 'does not match other gitlab urls that contain the term metrics' do
-      url = Gitlab::Routing.url_helpers.active_common_namespace_project_prometheus_metrics_url('foo', 'bar', :json)
+    subject { described_class.regex }
 
-      expect(described_class.regex).not_to match url
+    it_behaves_like 'a regex which matches the expected url'
+    it_behaves_like 'does not match non-matching urls'
   end
 
-    it 'does not match other gitlab urls' do
-      url = Gitlab.config.gitlab.url
+  describe '#grafana_regex' do
+    let(:url) do
+      Gitlab::Routing.url_helpers.namespace_project_grafana_api_metrics_dashboard_url(
+        'foo',
+        'bar',
+        start: '2019-08-02T05:43:09.000Z',
+        dashboard: 'config/prometheus/common_metrics.yml',
+        group: 'awesome group',
+        anchor: 'title'
+      )
+    end
 
-      expect(described_class.regex).not_to match url
+    let(:expected_params) do
+      {
+        'url' => url,
+        'namespace' => 'foo',
+        'project' => 'bar',
+        'query' => '?dashboard=config%2Fprometheus%2Fcommon_metrics.yml&group=awesome+group&start=2019-08-02T05%3A43%3A09.000Z',
+        'anchor' => '#title'
+      }
     end
 
-    it 'does not match non-gitlab urls' do
-      url = 'https://www.super_awesome_site.com/'
+    subject { described_class.grafana_regex }
 
-      expect(described_class.regex).not_to match url
-    end
+    it_behaves_like 'a regex which matches the expected url'
+    it_behaves_like 'does not match non-matching urls'
   end
 
   describe '#build_dashboard_url' do