Remove action_mailer

We're no longer using `ActionMailer` to send emails so we can safely
remove code that references it.

app/jobs/notify_delivery_job.rb

@@ -1,12 +1,14 @@
 # frozen_string_literal: true
 
+require "notifications/client"
+
 class NotifyDeliveryJob < ApplicationJob
-  queue_as { Rails.configuration.action_mailer.deliver_later_queue_name }
+  queue_as :mailer
 
   def self.client
     @client ||=
       Notifications::Client.new(
-        Rails.configuration.action_mailer.notify_settings[:api_key]
+        Settings.govuk_notify["#{Settings.govuk_notify.mode}_key"]
       )
   end
 
@@ -15,11 +17,11 @@ def self.deliveries
   end
 
   def self.send_via_notify?
-    Rails.configuration.action_mailer.delivery_method == :notify
+    Settings.govuk_notify&.enabled
   end
 
   def self.send_via_test?
-    Rails.configuration.action_mailer.delivery_method == :test
+    Rails.env.test?
   end
 
   class UnknownTemplate < StandardError

config/application.rb

@@ -64,8 +64,6 @@ class Application < Rails::Application
     config.active_job.queue_adapter = :good_job
     config.good_job.execution_mode = :async
 
-    config.action_mailer.deliver_later_queue_name = :mailer
-
     config.view_component.default_preview_layout = "component_preview"
     config.view_component.preview_controller = "ComponentPreviewsController"
     config.view_component.preview_paths << Rails.root.join(

config/environments/development.rb

@@ -36,25 +36,6 @@
   # Store uploaded files on the local file system (see config/storage.yml for options).
   config.active_storage.service = :local
 
-  # Don't care if the mailer can't send.
-  config.action_mailer.raise_delivery_errors = false
-
-  # Make template changes take effect immediately.
-  config.action_mailer.perform_caching = false
-
-  # Set localhost to be used by links generated in mailer templates.
-  config.action_mailer.default_url_options = { host: "localhost", port: 4000 }
-
-  if Settings.govuk_notify&.enabled
-    config.action_mailer.delivery_method = :notify
-    config.action_mailer.notify_settings = {
-      api_key: Settings.govuk_notify["#{Settings.govuk_notify.mode}_key"]
-    }
-  else
-    config.action_mailer.default_options = { from: "[email protected]" }
-    config.action_mailer.delivery_method = :file
-  end
-
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log
 

config/environments/production.rb

@@ -77,27 +77,6 @@
   # Replace the default in-process and non-durable queuing backend for Active Job.
   # config.active_job.queue_adapter = :resque
 
-  # Ignore bad email addresses and do not raise email delivery errors.
-  # Set this to true and configure the email server for immediate delivery to raise delivery errors.
-  # config.action_mailer.raise_delivery_errors = false
-
-  # Set host to be used by links generated in mailer templates.
-  config.action_mailer.default_url_options = {
-    host:
-      if Settings.is_review
-        "#{ENV["HEROKU_APP_NAME"]}.herokuapp.com"
-      else
-        Settings.host
-      end,
-    protocol: "https"
-  }
-
-  # Configure GOV.UK Notify.
-  config.action_mailer.delivery_method = :notify
-  config.action_mailer.notify_settings = {
-    api_key: Settings.govuk_notify.live_key
-  }
-
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation cannot be found).
   config.i18n.fallbacks = true

config/environments/staging.rb

@@ -20,8 +20,4 @@
       description: "Track the status of DPS exports"
     }
   )
-
-  config.action_mailer.notify_settings = {
-    api_key: Settings.govuk_notify["#{Settings.govuk_notify.mode}_key"]
-  }
 end

config/environments/test.rb

@@ -35,15 +35,6 @@
   # Store uploaded files on the local file system in a temporary directory.
   config.active_storage.service = :test
 
-  # Tell Action Mailer not to deliver emails to the real world.
-  # The :test delivery method accumulates sent emails in the
-  # ActionMailer::Base.deliveries array.
-  config.action_mailer.delivery_method = :test
-
-  # Set host to be used by links generated in mailer templates.
-  config.action_mailer.default_url_options = { host: "localhost:4000" }
-  config.action_mailer.default_options = { from: "[email protected]" }
-
   # Print deprecation notices to the stderr.
   config.active_support.deprecation = :stderr
 

config/settings/test.yml

@@ -7,6 +7,10 @@ cis2:
   issuer: "http://localhost:4000/test/oidc"
   client_id: "31337.apps.national"
 
+govuk_notify:
+  enabled: false
+  mode: test
+
 mesh:
   base_url: https://localhost:8700
   disable_ssl_verification: true

spec/jobs/email_delivery_job_spec.rb

@@ -2,11 +2,11 @@
 
 describe EmailDeliveryJob do
   before(:all) do
-    Rails.configuration.action_mailer.delivery_method = :notify
-    Rails.configuration.action_mailer.notify_settings = { api_key: "abc" }
+    Settings.govuk_notify.enabled = true
+    Settings.govuk_notify.test_key = "abc"
   end
 
-  after(:all) { Rails.configuration.action_mailer.delivery_method = :test }
+  after(:all) { Settings.govuk_notify.enabled = false }
 
   let(:response) do
     instance_double(

spec/jobs/sms_delivery_job_spec.rb

@@ -2,11 +2,11 @@
 
 describe SMSDeliveryJob do
   before(:all) do
-    Rails.configuration.action_mailer.delivery_method = :notify
-    Rails.configuration.action_mailer.notify_settings = { api_key: "abc" }
+    Settings.govuk_notify.enabled = true
+    Settings.govuk_notify.test_key = "abc"
   end
 
-  after(:all) { Rails.configuration.action_mailer.delivery_method = :test }
+  after(:all) { Settings.govuk_notify.enabled = false }
 
   let(:response) do
     instance_double(