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Senior Developer

Email Logging in Drupal

There are a number of scenarios where you might want to log email being sent by Drupal; perhaps locally during development or for urgent debugging on a live site. There are a number of options available for Drupal email logging, and this article will cover four of the most common ways:

We'll look at the main pro's, con's and technical overhead involved in each. I won't go into too much technical detail about setting things up, but hopefully you'll get and idea of the options available when you next find yourself wanting to log email from your Drupal site.

Devel Module

This is the simplest of the options, especially if you (like us) almost invariably have the Devel module kicking around your development Drupal install (if you're not familiar with devel, go check it out; it's massively handy).

The steps involved:

  1. Download Devel from the project page and enable it.
  2. Visit the devel module configuration page.
  3. Set the 'SMTP library' option to 'log only'.
  4. View the emails in the watchdog at admin/reports/dblog

It should be noted that this method isn't really suitable for use on live sites. Besides the fact that Devel isn't usually recommended for use in a live environment, none of the emails will ever make it any further than the log, meaning users won't get them, which is obviously bad news on a live site. It should also be noted that this only works in the Drupal 6 version of Devel, as the functionality was dropped in the D7 version.

Drupal logging modules

There are several other modules available with the specific purpose of logging emails within Drupal. Maillog for example allows you to log all emails sent by the system, viewable at admin/settings/maillog. Furthermore, you can optionally block emails from proceeding further, which arguably makes it the most flexible for use in a live environment. This is a nice simple solution when a log is the most helpful way to monitor things.

Drupal re-routing modules

Sometimes you need more than a plain text log - debugging HTML email for example isn't practical from within the Drupal interface. What's needed in this case is viewing in an email client. There are again several modules available that will help you achieve this. They will catch email leaving Drupal and redirect to a given email address. For a wholesale approach, there's Reroute Email, or for more complex routing rules there's Advanced Mail Reroute.

Re-routing e-mails in this way will once again prevent the original recipient from recieving the email, so is perhaps most useful during development or if you are working with a live database dump and wish to prevent emails getting to users.

SMTP rerouting

The most complex but ultimately powerful solution is custom configuration of a SMTP server on the machine the site is running on. On a unix system, postfix (or other SMTP server) can be configured in any number of ways, to block, redirect or BCC any outbound (or indeed inbound) e-mail. So during development, you might configure your local machine to catch all outbound e-mail sent by PHP and redirect it locally, for viewing in an appropriately configured e-mail client of you choosing.

This big win of this is that you only need do this locally once, after which you'll get all the e-mail sent by any of the sites you have set up on your machine. Furthermore, in a UAT/QA or live context, the server could be configured to silently BCC all outbound email to some defined address (though be aware of any potential privacy/legal issues with doing so).

Server configuration is obviously the most powerful solution for Drupal email logging, and elegant too, in that it doesn't touch your Drupal codebase or change the execution of PHP at all. It would also work for any other applications you have installed sending email via the server's built-in SMTP libraries (should you also work in some other framework/CMS than Drupal). It is however the most difficult to set up, requiring some significant sysadmin chops to configure. Certainly tinkering with this in a live environment would be best left to someone who knows what they're doing.

Looking to Drupal 7

Depending on the environment, one of these solutions should be appropriate to fit your Drupal e-mail logging needs. Presuming, that is, you're still only working with Drupal 6. The only option currently 'ready' for Drupal 7 is the SMTP server configuration choice, whilst the module closest to a stable release looks to be Reroute Email.


Thanks for taking the time to write this down. This is well-written and a good reference for developers.

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