Match both metrics and metrics dashboard in entirenty

Embedding metrics in GitLab flavored markdown is triggered
by the presence of a dashboard url. This fixes a bug where
query params where not acknowledged for embeds at the default
metrics_dashboard route.

changelogs/unreleased/sy-fix-transient-embed-again.yml

+---
+title: Embed metrics charts for both /metrics and /metrics_dashboard routes
+merge_request: 29838
+author:
+type: fixed

lib/gitlab/metrics/dashboard/url.rb

@@ -23,7 +23,7 @@ module Gitlab
                 %r{
                     /environments
                     /(?<environment>\d+)
-                    /metrics
+                    /(metrics_dashboard|metrics)
                 }x
               )
             end

spec/features/markdown/metrics_spec.rb

@@ -137,7 +137,7 @@ describe 'Metrics rendering', :js, :use_clean_rails_memory_store_caching, :sidek
   end
 
   context 'transient metrics embeds' do
-    let(:metrics_url) { urls.metrics_project_environment_url(project, environment, embed_json: embed_json) }
+    let(:metrics_url) { urls.metrics_dashboard_project_environment_url(project, environment, embed_json: embed_json) }
     let(:title) { 'Important Metrics' }
     let(:embed_json) do
       {

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

@@ -3,17 +3,21 @@
 require 'spec_helper'
 
 describe Gitlab::Metrics::Dashboard::Url do
+  include Gitlab::Routing.url_helpers
+
   describe '#metrics_regex' do
-    let(:url) do
-      Gitlab::Routing.url_helpers.metrics_namespace_project_environment_url(
+    let(:url_params) do
+      [
         'foo',
         'bar',
         1,
-        start: '2019-08-02T05:43:09.000Z',
-        dashboard: 'config/prometheus/common_metrics.yml',
-        group: 'awesome group',
-        anchor: 'title'
-      )
+        {
+          start: '2019-08-02T05:43:09.000Z',
+          dashboard: 'config/prometheus/common_metrics.yml',
+          group: 'awesome group',
+          anchor: 'title'
+        }
+      ]
     end
 
     let(:expected_params) do
@@ -29,12 +33,22 @@ describe Gitlab::Metrics::Dashboard::Url do
 
     subject { described_class.metrics_regex }
 
-    it_behaves_like 'regex which matches url when expected'
+    context 'for metrics route' do
+      let(:url) { metrics_namespace_project_environment_url(*url_params) }
+
+      it_behaves_like 'regex which matches url when expected'
+    end
+
+    context 'for metrics_dashboard route' do
+      let(:url) { metrics_dashboard_namespace_project_environment_url(*url_params) }
+
+      it_behaves_like 'regex which matches url when expected'
+    end
   end
 
   describe '#grafana_regex' do
     let(:url) do
-      Gitlab::Routing.url_helpers.namespace_project_grafana_api_metrics_dashboard_url(
+      namespace_project_grafana_api_metrics_dashboard_url(
         'foo',
         'bar',
         start: '2019-08-02T05:43:09.000Z',