dmke / cronmail

Send a periodical email for simple monitoring purpose.

Cronmail

Ruby server-side script for periodic status messages via email.

These status messages includes the average load, currently logged in users (number and origin), the uptime, free memory and a process list.

The email is send multipart'ed (text/plain and text/html).

Requirements

You need at least this setup on your machine:

• Ruby and RubyGems,
• the actionmailer gem ((sudo) gem install actionmailer),
• a running cron daemon, and a sendmail-compatible MTA.

I've tested Cronmail with a Debian Squeeze (Ruby 1.9.2, RubyGems 1.3.7, Vixie Cron 3.0, Postfix 2.7.1 and ActionMailer 3.0.5).

Installation

First, clone this repository:

$ git clone git://github.com/dmke/cronmail.git

Then edit the configuration file:

$ cd /path/to/cloned/cronmail
$ cp cronmail.yml.example cronmail.yml
$ $EDITOR cronmail.yml

There, you may change the senders field (:from) and the list of recipients (:recipients). The :action_mailer fields are for future purpose and currently not supported.

After finishing the configuration, test your Cronmail installation:

$ cd /path/to/cloned/cronmail
$ ruby cronmail.rb

If there is no output and you've received an email with "I am alive!" subject, you may continue with setting up a cronjob (else read the FAQ, below):

$ crontab -e
$ # insert a line like this:
$ # */10 * * * * /usr/bin/ruby /path/to/cloned/cronmail/cronmail.rb >/dev/null 2>&1

This will send your recipients every ten minutes a status report. See crontab(8) for more details.

FAQ

1. I have an error or any output while testing.

   • Consider this:
     • Ensure to have some recent versions of Ruby, RubyGems, Cron and your MTA installed.
     • Ensure to have them configured correctly.
     • Check the log messages of your MTA, may be the recipients are rejecting your host for some (good) reason.

2. I still receive no mail.

   • Have you checked your junk filter?
   • Ensure Cron and your MTA are running.

3. I'd like to have an email only at startup time, is that possible?

   • Sure, if your cron daemon allows you to be configured this way, like Vixie Cron, why not?
   • RTFM, crontab(8)

4. I don't have a cron daemon installed, is there another way to send status emails periodically?

   • That might be possible in a future version of Cronmail.
   • Seriously? You're running a server without any crond? How do you...?