1 files changed, 46 insertions, 0 deletions
diff --git a/actionmailer/lib/action_mailer/log_subscriber.rb b/actionmailer/lib/action_mailer/log_subscriber.rb
new file mode 100644
index 0000000000..25c99342c2
--- /dev/null
+++ b/actionmailer/lib/action_mailer/log_subscriber.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "active_support/log_subscriber"
+
+module ActionMailer
+  # Implements the ActiveSupport::LogSubscriber for logging notifications when
+  # email is delivered or received.
+  class LogSubscriber < ActiveSupport::LogSubscriber
+    # An email was delivered.
+    def deliver(event)
+      info do
+        perform_deliveries = event.payload[:perform_deliveries]
+        recipients = Array(event.payload[:to]).join(", ")
+        if perform_deliveries
+          "Sent mail to #{recipients} (#{event.duration.round(1)}ms)"
+        else
+          "Skipped sending mail to #{recipients} as `perform_deliveries` is false"
+        end
+      end
+
+      debug { event.payload[:mail] }
+    end
+
+    # An email was received.
+    def receive(event)
+      info { "Received mail (#{event.duration.round(1)}ms)" }
+      debug { event.payload[:mail] }
+    end
+
+    # An email was generated.
+    def process(event)
+      debug do
+        mailer = event.payload[:mailer]
+        action = event.payload[:action]
+        "#{mailer}##{action}: processed outbound mail in #{event.duration.round(1)}ms"
+      end
+    end
+
+    # Use the logger configured for ActionMailer::Base.
+    def logger
+      ActionMailer::Base.logger
+    end
+  end
+end
+
+ActionMailer::LogSubscriber.attach_to :action_mailer