How to implement a mailing system with Rails that sends emails in the background

Question

I want to implement a reliable mailing system with Ruby on Rails that sends emails in the background as sending email sometimes takes like 10 seconds or more so I don't want the user to wait. Some ideas I thought of:

1. Write to a table in DB a have a background process that go over and send email (concern: potential many reads/writes to DB slows down my application)

2. Messaging Queue background process / Rake task (concern: if server crashes queued mails will be lost also might eat up a lot of memory if many emails)

I was wondering if you a know of a good solution that provides a balance between reliability and performance.

Answer 1

Have you looked at the mail-queue plugin?

http://code.google.com/p/mail-queue/

The docs seem to suggest it stores the mails in a DB table, thus avoiding #2 at least.

Answer 2

I think Starling and Workling will be able to assist you =) Watch this railscast: http://railscasts.com/episodes/128-starling-and-workling

Answer 3

You can implement the feature or rely on external services.

I have been using PostageApp for the last 2 months and I'm really happy with it. An other solution is Postmark.

Otherwise, if you want to code it, first you need a queue system. For Rails, you can use DelayedJob or Resque. Sending emails in the background is probably the most simple solution, the "problem" is dealing with failures and retry.