Implement action mailer delivery metrics observer

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/gitlab/email/hook/delivery_metrics_observer.rb b/lib/gitlab/email/hook/delivery_metrics_observer.rb
new file mode 100644
index 00000000000..1c2985f6045
--- /dev/null
+++ b/lib/gitlab/email/hook/delivery_metrics_observer.rb
@@ -0,0 +1,31 @@
+module Gitlab
+  module Email
+    module Hook
+      class DeliveryMetricsObserver
+        extend Gitlab::Utils::StrongMemoize
+
+        def self.delivering_email(_message)
+          delivery_attempts_counter.increment
+        end
+
+        def self.delivered_email(_message)
+          delivered_emails_counter.increment
+        end
+
+        def self.delivery_attempts_counter
+          strong_memoize(:delivery_attempts_counter) do
+            Gitlab::Metrics.counter(:gitlab_emails_delivery_attempts_total,
+                                    'Counter of total emails delivery attempts')
+          end
+        end
+
+        def self.delivered_emails_counter
+          strong_memoize(:delivered_emails_counter) do
+            Gitlab::Metrics.counter(:gitlab_emails_delivered_total,
+                                    'Counter of total emails delievered')
+          end
+        end
+      end
+    end
+  end
+end