1 files changed, 41 insertions, 0 deletions
diff --git a/lib/gitlab/metrics/prometheus.rb b/lib/gitlab/metrics/prometheus.rb
new file mode 100644
index 00000000000..60686509332
--- /dev/null
+++ b/lib/gitlab/metrics/prometheus.rb
@@ -0,0 +1,41 @@
+require 'prometheus/client'
+
+module Gitlab
+  module Metrics
+    module Prometheus
+      include Gitlab::CurrentSettings
+
+      def prometheus_metrics_enabled?
+        @prometheus_metrics_enabled ||= current_application_settings[:prometheus_metrics_enabled] || false
+      end
+
+      def registry
+        @registry ||= ::Prometheus::Client.registry
+      end
+
+      def counter(name, docstring, base_labels = {})
+        provide_metric(name) || registry.counter(name, docstring, base_labels)
+      end
+
+      def summary(name, docstring, base_labels = {})
+        provide_metric(name) || registry.summary(name, docstring, base_labels)
+      end
+
+      def gauge(name, docstring, base_labels = {})
+        provide_metric(name) || registry.gauge(name, docstring, base_labels)
+      end
+
+      def histogram(name, docstring, base_labels = {}, buckets = ::Prometheus::Client::Histogram::DEFAULT_BUCKETS)
+        provide_metric(name) || registry.histogram(name, docstring, base_labels, buckets)
+      end
+
+      def provide_metric(name)
+        if prometheus_metrics_enabled?
+          registry.get(name)
+        else
+          NullMetric.new
+        end
+      end
+    end
+  end
+end