Expose metrics element for FE consumption

Adds GFM Pipline filters to insert a placeholder in the generated
HTML from GFM based on the presence of a metrics dashboard link.

The front end should look for the class 'js-render-metrics' to
determine if it should replace the element with metrics charts.
The data element 'data-dashboard-url' should be the endpoint
the front end should hit in order to obtain a dashboard layout
in order to appropriately render the charts.

1 files changed, 56 insertions, 0 deletions

diff --git a/spec/lib/gitlab/metrics/dashboard/url_spec.rb b/spec/lib/gitlab/metrics/dashboard/url_spec.rb
new file mode 100644
index 00000000000..34bc6359414
--- /dev/null
+++ b/spec/lib/gitlab/metrics/dashboard/url_spec.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+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
+
+    it 'matches a metrics dashboard link with named params' do
+      url = Gitlab::Routing.url_helpers.metrics_namespace_project_environment_url('foo', 'bar', 1, start: 123345456, anchor: 'title')
+
+      expected_params = {
+        'url' => url,
+        'namespace' => 'foo',
+        'project' => 'bar',
+        'environment' => '1',
+        'query' => '?start=123345456',
+        '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)
+
+      expect(described_class.regex).not_to match url
+    end
+
+    it 'does not match other gitlab urls' do
+      url = Gitlab.config.gitlab.url
+
+      expect(described_class.regex).not_to match url
+    end
+
+    it 'does not match non-gitlab urls' do
+      url = 'https://www.super_awesome_site.com/'
+
+      expect(described_class.regex).not_to match url
+    end
+  end
+
+  describe '#build_dashboard_url' do
+    it 'builds the url for the dashboard endpoint' do
+      url = described_class.build_dashboard_url('foo', 'bar', 1)
+
+      expect(url).to match described_class.regex
+    end
+  end
+end