The delayed_job_tracer gem is designed to monitor the delayed_job gem, which was extracted from Shopify (http://github.com/tobi/delayed_job), but is now maintained at (https://github.com/collectiveidea/delayed_job). It will alert you via e-mail if something goes wrong, such as if the delayed_job process crashes or one of its jobs fails or takes too long to complete.
This gem also detects wither e-mails sent through delayed_job are actually being delivered by sending test messages (like tracer bullets) to an e-mail account then checking that account to ensure they were processed and dispatched via the delayed_job queue. The e-mail delivery detection allows you to be notified if e-mails can’t be sent out either because of delayed_job having choked or because of an issue with the e-mail account the application uses to send e-mail.
- Sends an e-mail notification when delayed_job crashes or is unable to complete a job in a reasonable amount of time.
- Sends an e-mail notification when the Rails application is unable to successfully deliver e-mails via delayed_job.
- Circumvents the need for a process monitoring tool like Monit or God for delayed_job processes.
- Keeps memory usage low by working outside of Rails.
Why use a Cron’d ruby process to monitor delayed_job and e-mail delivery?
- Cron is often considered to be more reliable than process monitoring tools like Monit or God.
- The Cron’d Ruby process only uses a modest amount of memory (~27MB) for a few seconds at regular intervals, whereas a rake task or runner would equate to the entire size of the Rails application, with a memory footprint that grows over time.
Why use a Perl Script to send alert e-mails to admins?
- It’s fast
- It doesn’t rely on the Rails application
- It doesn’t rely on the delayed_job process you’re monitoring with this gem
1) Install XML and SSL Packages:
Note: These are for Ubuntu. You may need to find alternate packages for your platform.
sudo apt-get install libxml2-dev libxslt-dev libnet-ssleay-perl libcrypt-ssleay-perl libio-socket-ssl-perl
2) sendEmail Perl script:
Download from http://caspian.dotconf.net/menu/Software/SendEmail and follow the setup instructions, or just follow these instructions:
wget -c http://caspian.dotconf.net/menu/Software/SendEmail/sendEmail-v1.56.tar.gz tar xvfz sendEmail-v1.56.tar.gz sudo cp -a sendEmail-v1.56/sendEmail /usr/local/bin chmod +x /usr/local/bin/sendEmail
Run it to be sure it works:
rm -rf sendEmail-v1.56*
1) Add the gem to your Gemfile:
2) Generate the config file:
rails g delayed_job_tracer
- Create a ‘DelayedJobTracer’ folder/label in the e-mail account you configure the plugin to send test messages to and a filter to move all incoming messages with ‘[DelayedJobTracer]’ in the subject line to this folder (or label if you’re using Gmail). Set the name of this folder in the config/delayed_job_tracer_config.yml file – as it will be the folder that the Ruby process checks for test messages.
- Add a Cron job on the server:
Example for running every 15 minutes, replace with your actual app and ruby locations:
*/15 * * * * /usr/local/bin/delayed_job_tracer -c /opt/apps/appname/current/config/delayed_job_tracer_config.yml
Note: If you’re using bundler to install gems within an application-specific gem environment, you may need to also install the gem manually on the server so that the executable is available via the location in the example cron entry above.
- Finish configuring your settings in the config/delayed_job_tracer_config.yml file. Your database and ActionMailer config will be applied via the generator, but you’ll still need to provide an alternate e-mail account to send administrative notifications through, provide the admin’s e-mail address and so forth.
The MIT License
Copyright © 2010-2011 Kenny Johnston
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