spool.rst

How to Spool Email

When you are using the SwiftmailerBundle to send emails from a Symfony2 application it will by default send the email immediately. You may want to avoid the performance hit of the communication between Swiftmailer and the email transport taking place at the time. This can be avoided by choosing to spool the emails instead of sending them directly. This means that Swiftmailer does not attempt to send the email but instead saves the message to somewhere such as a file. Another process can then read from the spool and take care of sending of the email. Currently only spooling to file is supported by Swiftmailer.

In order to use the spool you will need to use the following config:

# app/config/config.yml
swiftmailer:
    # ...
    spool:
        type: file
        path: /path/to/spool

<!-- app/config/config.xml -->

<!--
xmlns:swiftmailer="http://symfony.com/schema/dic/swiftmailer"
http://symfony.com/schema/dic/swiftmailer http://symfony.com/schema/dic/swiftmailer/swiftmailer-1.0.xsd
-->

<swiftmailer:config>
     <swiftmailer:spool
         type="file"
         path="/path/to/spool" />
</swiftmailer:config>

// app/config/config.php
$container->loadFromExtension('swiftmailer', array(
     // ...
    'spool' => array(
        'type' => 'file',
        'path' => '/path/to/spool',
    )
));

Now when your app sends an email it will not actually be sent but added to the spool. Sending the messages from the spool is done separately. There is a console command to send the messages in the spool:

php app/console swiftmailer:spool:send

It has an option to limit the number of messages to be sent:

php app/console swiftmailer:spool:send --message-limit=10

You can also set the time limit in seconds:

php app/console swiftmailer:spool:send --time-limit=10

Of course you will not want to run this manually in actual use, the console command should be triggered by a cron job or scheduled task and run at a regular interval.