1 files changed, 50 insertions, 0 deletions
diff --git a/lib/gitlab/metrics/samplers/unicorn_sampler.rb b/lib/gitlab/metrics/samplers/unicorn_sampler.rb
new file mode 100644
index 00000000000..ea325651fbb
--- /dev/null
+++ b/lib/gitlab/metrics/samplers/unicorn_sampler.rb
@@ -0,0 +1,50 @@
+module Gitlab
+  module Metrics
+    module Samplers
+      class UnicornSampler < BaseSampler
+        def initialize(interval)
+          super(interval)
+        end
+
+        def unicorn_active_connections
+          @unicorn_active_connections ||= Gitlab::Metrics.gauge(:unicorn_active_connections, 'Unicorn active connections', {}, :max)
+        end
+
+        def unicorn_queued_connections
+          @unicorn_queued_connections ||= Gitlab::Metrics.gauge(:unicorn_queued_connections, 'Unicorn queued connections', {}, :max)
+        end
+
+        def enabled?
+          # Raindrops::Linux.tcp_listener_stats is only present on Linux
+          unicorn_with_listeners? && Raindrops::Linux.respond_to?(:tcp_listener_stats)
+        end
+
+        def sample
+          Raindrops::Linux.tcp_listener_stats(tcp_listeners).each do |addr, stats|
+            unicorn_active_connections.set({ type: 'tcp', address: addr }, stats.active)
+            unicorn_queued_connections.set({ type: 'tcp', address: addr }, stats.queued)
+          end
+
+          Raindrops::Linux.unix_listener_stats(unix_listeners).each do |addr, stats|
+            unicorn_active_connections.set({ type: 'unix', address: addr }, stats.active)
+            unicorn_queued_connections.set({ type: 'unix', address: addr }, stats.queued)
+          end
+        end
+
+        private
+
+        def tcp_listeners
+          @tcp_listeners ||= Unicorn.listener_names.grep(%r{\A[^/]+:\d+\z})
+        end
+
+        def unix_listeners
+          @unix_listeners ||= Unicorn.listener_names - tcp_listeners
+        end
+
+        def unicorn_with_listeners?
+          defined?(Unicorn) && Unicorn.listener_names.any?
+        end
+      end
+    end
+  end
+end