1 files changed, 72 insertions, 0 deletions
diff --git a/lib/gitlab/metrics/subscribers/action_cable.rb b/lib/gitlab/metrics/subscribers/action_cable.rb
new file mode 100644
index 00000000000..a9355eeae40
--- /dev/null
+++ b/lib/gitlab/metrics/subscribers/action_cable.rb
@@ -0,0 +1,72 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Metrics
+    module Subscribers
+      class ActionCable < ActiveSupport::Subscriber
+        include Gitlab::Utils::StrongMemoize
+
+        attach_to :action_cable
+
+        SINGLE_CLIENT_TRANSMISSION = :action_cable_single_client_transmissions_total
+        TRANSMIT_SUBSCRIPTION_CONFIRMATION = :action_cable_subscription_confirmations_total
+        TRANSMIT_SUBSCRIPTION_REJECTION = :action_cable_subscription_rejections_total
+        BROADCAST = :action_cable_broadcasts_total
+
+        def transmit_subscription_confirmation(event)
+          confirm_subscription_counter.increment
+        end
+
+        def transmit_subscription_rejection(event)
+          reject_subscription_counter.increment
+        end
+
+        def transmit(event)
+          transmit_counter.increment
+        end
+
+        def broadcast(event)
+          broadcast_counter.increment
+        end
+
+        private
+
+        def transmit_counter
+          strong_memoize("transmission_counter") do
+            ::Gitlab::Metrics.counter(
+              SINGLE_CLIENT_TRANSMISSION,
+              'The number of ActionCable messages transmitted to any client in any channel'
+            )
+          end
+        end
+
+        def broadcast_counter
+          strong_memoize("broadcast_counter") do
+            ::Gitlab::Metrics.counter(
+              BROADCAST,
+              'The number of ActionCable broadcasts emitted'
+            )
+          end
+        end
+
+        def confirm_subscription_counter
+          strong_memoize("confirm_subscription_counter") do
+            ::Gitlab::Metrics.counter(
+              TRANSMIT_SUBSCRIPTION_CONFIRMATION,
+              'The number of ActionCable subscriptions from clients confirmed'
+            )
+          end
+        end
+
+        def reject_subscription_counter
+          strong_memoize("reject_subscription_counter") do
+            ::Gitlab::Metrics.counter(
+              TRANSMIT_SUBSCRIPTION_REJECTION,
+              'The number of ActionCable subscriptions from clients rejected'
+            )
+          end
+        end
+      end
+    end
+  end
+end