Merge branch '51333-use-rails-root-for-common-metrics-importer' into 'master'

Use Rails.root for CommonMetricsImporter

Closes #51333

See merge request gitlab-org/gitlab-ce!21664

db/importers/common_metrics_importer.rb

@@ -35,8 +35,8 @@ module Importers
 
     attr_reader :content
 
-    def initialize(file = 'config/prometheus/common_metrics.yml')
-      @content = YAML.load_file(file)
+    def initialize(filename = 'common_metrics.yml')
+      @content = YAML.load_file(Rails.root.join('config', 'prometheus', filename))
     end
 
     def execute

spec/db/importers/common_metrics_importer_spec.rb

@@ -47,6 +47,16 @@ describe Importers::CommonMetricsImporter do
     end
   end
 
+  context "does import common_metrics.yml" do
+    it "when executed from outside of the Rails.root" do
+      Dir.chdir(Dir.tmpdir) do
+        expect { subject.execute }.not_to raise_error
+      end
+
+      expect(PrometheusMetric.common).not_to be_empty
+    end
+  end
+
   context 'does import properly all fields' do
     let(:query_identifier) { 'response-metric' }
     let(:group) do