openlabs_email_queue 3.4.0.1

Trytond Email Queue Module

This module implements an email queue which acts as a transaction safe buffer for tryton modules to send emails.

Source code: https://github.com/openlabs/email-queue

Why should I use this module ?

Do you send emails from your tryton module ? Then you most probably need this module. Here’s why:

Transaction Safety

Consider the case where you are sending an Order confirmation email when you click the confirm button. The transaction could roll back for a variety of reasons after the email has been sent out to the customer. This could be specially annoying if you sent an order number or other information which could change, the second time you save the record - in addition to the second time the second email that would spam the user.

This module solves the problem by buffering the email to a database table within the same transaction. Later, a cron task clears out the email. If the transaction was rolled back the would not be saved in the buffer too and you would not have to do anything separate.

Performance

Depending on how your SMTP server is setup and the bandwidth of your servers, the sending of an email takes way more time than a database write. This creates blocking operations resulting in poor user experience and your app would now need more workers to handle more such requests. This module works around the problem by first buffering the email and then having a separate cron task which clears out the email by actually sending it.

Scalability

If you desire to be webscale like most of the internet aspires to be, you would probably want to perform network bound operations like sending emails from separate servers and scale using a message queue. This module offers an API which lets you easily scale by subclassing the email.queue model and changing the send_all implementation.

How do I install this module ?

Install from PyPI:

pip install openlabs_email_queue

Install from source:

git clone [e-mail]:openlabs/email-queue
python setup.py install

You can then install the module in your database.

How do I use this functionality in my modules ?

The module provides a convenient method which has the same signature as python’s smtplib.SMTP.sendmail method. This makes it easy to update your existing email sending code.

msg = MIMEText('This is the body')
msg['Subject'] = 'An important email'
msg['From'] = '[e-mail]'
msg['To'] = '[e-mail]'

EmailQueue = Pool().get('email.queue')
EmailQueue.queue_mail(me, [you], msg.as_string())

If your transaction was successful, the email would be queued to be sent and the mail would be sent out through the SMTP server when the cron runs next time.

The cron runs every 1 minute and you can change the frequency from cron settings

How do I configure the SMTP Server ?

By default the emails are sent out using the smtp client provided by Tryton. You can configure the settings for the same on your tryton configuration file.

Authors and Contributors

This module was built at Openlabs.

Professional Support

This module is professionally supported by Openlabs. If you are looking for on-site teaching or consulting support, contact our sales and support teams.