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New Rails Plugin for making ActionMailer asynchronous

May 19, 2008 by alex

We have just released a new rails plugin called workling_mailer. This plugin provides a module which - when included into an ActionMailer subclass - pushes all emails that would normally be delivered synchronously into a queue for asynchronous processing. For queuing it relies on the workling plugin which can use for example twitter’s starling as a queue server.

We use this on autoki which sends a lot of email (thanks to our social feed plugin :) ).

Recently we got errors from the mailserver complaining about too many concurrent connections. This did not only cause emails not being delivered and our users getting an error page, it also caused long running transactions in the database: if you send an email within an after_create hook in a model this happens inside of the database transaction. That means that if you have a 60s timeout on your mail server you end up with database transactions taking 60s to finish (or being rolled back in this case) which essentially locks up your tables after a short period of time.

Now that we are sending our emails from a queue one at a time, the mailserver is happy and our database transactions are again as short as they should be.

You can get the sources at github.