Add incineration by default

app/jobs/action_mailroom/inbound_email/incineration_job.rb

@@ -0,0 +1,11 @@
+class ActionMailroom::InboundEmail::IncinerationJob < ApplicationJob
+  queue_as :action_mailroom_incineration
+
+  def self.schedule(inbound_email)
+    set(wait: ActionMailroom::InboundEmail::Incineratable::INCINERATABLE_AFTER).perform_later(inbound_email)
+  end
+
+  def perform(inbound_email)
+    inbound_email.incinerate
+  end
+end

app/models/action_mailroom/inbound_email.rb

@@ -1,6 +1,8 @@
 require "mail"
 
 class ActionMailroom::InboundEmail < ActiveRecord::Base
+  include Incineratable
+
   self.table_name = "action_mailroom_inbound_emails"
 
   has_one_attached :raw_email

app/models/action_mailroom/inbound_email/incineratable.rb

@@ -0,0 +1,31 @@
+module ActionMailroom::InboundEmail::Incineratable
+  extend ActiveSupport::Concern
+
+  # TODO: Extract into framework configuration
+  INCINERATABLE_AFTER = 30.days
+
+  included do
+    before_update :remember_to_incinerate_later
+    after_update_commit :incinerate_later, if: :need_to_incinerate_later?
+  end
+
+  def incinerate
+    Incineration.new(self).run
+  end
+
+  private
+    # TODO: Use enum change tracking once merged into Active Support
+    def remember_to_incinerate_later
+      if status_changed? && (delivered? || failed?)
+        @incinerate_later = true
+      end
+    end
+
+    def need_to_incinerate_later?
+      @incinerate_later
+    end
+
+    def incinerate_later
+      ActionMailroom::InboundEmail::IncinerationJob.schedule(self)
+    end
+end

app/models/action_mailroom/inbound_email/incineratable/incineration.rb

@@ -0,0 +1,18 @@
+class ActionMailroom::InboundEmail::Incineratable::Incineration
+  def initialize(inbound_email)
+    @inbound_email = inbound_email
+  end
+
+  def run
+    @inbound_email.destroy if due? && processed?
+  end
+
+  private
+    def due?
+      @inbound_email.updated_at < ActionMailroom::InboundEmail::Incineratable::INCINERATABLE_AFTER.ago.end_of_day
+    end
+
+    def processed?
+      @inbound_email.delivered? || @inbound_email.failed?
+    end
+end

test/unit/inbound_email/incineration_test.rb

@@ -0,0 +1,14 @@
+require_relative '../../test_helper'
+
+class ActionMailroom::InboundEmail::IncinerationTest < ActiveSupport::TestCase
+  include ActiveJob::TestHelper
+
+  test "incinerate emails 30 days after they have been processed" do
+    freeze_time
+
+    assert_enqueued_with job: ActionMailroom::InboundEmail::IncinerationJob, at: 30.days.from_now do
+      inbound_email = create_inbound_email("welcome.eml")
+      inbound_email.delivered!
+    end
+  end
+end