Friday, July 23, 2010

Sending outbound SMTP messages through Gmail with Mule ESB

I'm currently working on a Managed File Transfer (MFT) proof-of-concept for a client using Mule ESB Enterprise.  One of the requirements I had to address is the ability to send SMTP email messages when a particular connector failed, i.e. SFTP connection failed.  I thought to myself, that's a reasonable request and something that is probably straightforward to do in Mule ESB.  Well, if you look at the Mule configuration it is straightforward however, getting to that point using Gmail took some I thought I'd share :)

What you need...
  • Mule ESB (I'm using Mule ESB Enterprise Version: 2.2.5 Build: 16813 along with Mule Management Console support, i.e. mmc-agent-2.2.5.jar) *
  • A test Gmail account
* - if you plan on running the same version I am then there is a patch that needs to be applied to the mmc-agent-2.2.5.jar.  See JIRA issue MULE-4970.

Mule Configuration...
<?xml version="1.0"?>
<mule xmlns=""

  <description>Test configuration to send SMTP email through Gmail.</description>

  <!-- Configure some properties to work with GMail's SMTP -->
  <smtp:gmail-connector name="emailConnector" />

  <model name="processInboundFileModel">
    <service name="processInboundFileService">
<account name>"
<email addresses>"
<account name>"
            subject="Test email message"/>

As indicated, the Mule configuration is very straightforward.  You can get most of the information you need from the Mule SMTP Transport documentation except for what Gmail port to use and most importantly the gmail-connector information.  That tripped me up for a while until I came across a Mule JIRA issue where someone refer to the configuration in the bookstore example for sending email through Gmail.  I still haven't found much information on this connector and what it's doing but it does work and you need to use in order to connect to Gmail.

One other thing that is documented however maybe overlooked is that you need to replace the "@" symbol in the "user" attribute with the URL escape code of "%40".