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Verify database connections in long-running idle Rails processes

I've interfaced one of my xmpp4r bots with the Xeriom Networks control panel. I had intended to write a post about it to show how easy it is, but I've been beaten to it. I can, however, offer one piece of advice that will stop the bot dying after a few hours of idling: periodically verify your database connections.

RAILS_DEFAULT_LOGGER.debug "Launching database connection verifier"
Thread.new do
  loop do
    sleep 1800 # Half an hour
    RAILS_DEFAULT_LOGGER.debug "Verifying database connections"
    ActiveRecord::Base.verify_active_connections!
  end
end

Adding the above code to a script will stop database connections getting dropped (or, at least, will reconnect them if it happens).

To see it in action, add support@xeriom.net to your XMPP roster and have a chat. It's not hugely intelligent, but it does support a few useful commands.

Love me!

If you've found this article useful I'd appreciate beer and recommendations at Working With Rails.

XMPP4R-Simple makes XMPP in Ruby uhh... simple...

I thought it might be cool to have a control interface that you could talk to using IM, something like the IM client for Twitter.

Initially I was looking at XMPP4R but a little reading pointed out that there's a gem called XMPP4R-Simple. Well, simple is always good so one gem install and 45 minutes later I had a Ruby script that could log in to an XMPP server, listen to (and log) what people said, and respond with a simple message.

#!/usr/bin/env ruby

require 'rubygems'
require 'xmpp4r-simple'

logfile = File.join('..', 'log', "#{File.basename(__FILE__)}.log")
logger = Hodel3000CompliantLogger.new(logfile)

jabber = Jabber::Simple.new "username@domain.com", "password"
sleep 1
jabber.status(:away, "No one here but us mice.")
sleep 1

jabber.deliver("craig@xeriom.net", "I woke up at #{Time.now}.")

loop do  
  begin
    jabber.received_messages do |msg|
      jid = msg.from.strip.to_s
      logger.info "%s said: %s" % [ jid, msg.body ]
      jabber.add(jid) if !jabber.subscribed_to?(jid)
      jabber.deliver(jid, "Nom nom nom.")
    end

    jabber.presence_updates do |update|
      jid, status, message = *update
      logger.info "#{jid} is #{status} (#{message})"
    end

    jabber.new_subscriptions do |friend, presence|
      logger.info "#{friend.jid} #{presence.type}"
      jabber.add(friend.jid) if !jabber.subscribed_to?(friend.jid)
    end
  rescue Exception => e
    logger.error e.to_s
  end
  sleep 1
end

Our own little pet XMPP client. How cute is that?

Quit yo jibba jabba, sucka!

If you've found this article useful I'd appreciate recommendations at Working With Rails.

About the boy

A picture of Craig in grayscale

Hi, I'm Craig and I'm a Ruby coder. I live, work and play in London. I like scaling applications and eating yoghurt. Sometimes I climb rocks. Most of the time I climb back down.

You can contact me by email, MSN or Jabber. My address on all of these is craig@xeriom.net.

Code Licence

You can use any of the code on this blog in any way you want. It's totally public domain. You don't even need to attribute it to me, although it would be nice if you did. Just don't sue me.

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