add email events

app/mailers/application_mailer.rb

@@ -6,11 +6,32 @@ class ApplicationMailer < ActionMailer::Base
 
   register_interceptor ActionMailerConfigsInterceptor
 
+  register_observer ActionMailerEventsObserver
+
   before_action do
     ActiveStorage::Current.url_options = Docuseal.default_url_options
   end
 
+  after_action :set_message_metadata
+  after_action :set_message_uuid
+
   def default_url_options
     Docuseal.default_url_options
   end
+
+  def set_message_metadata
+    message.instance_variable_set(:@message_metadata, @message_metadata)
+  end
+
+  def set_message_uuid
+    message['X-Message-Uuid'] = SecureRandom.uuid
+  end
+
+  def assign_message_metadata(tag, record)
+    @message_metadata = {
+      'tag' => tag,
+      'record_id' => record.id,
+      'record_type' => record.class.name
+    }
+  end
 end