Build Status Lamp with Ruby and TeamCity

Recently at work we got our new build status light setup. We’re using TeamCity as our Continuous Integration Server, MSBuild as the build script, and a homemade Ruby Script to control the lamp.

The setup sits in our team room and looks like this:

The Build Lamp (a red lava lamp in this case) is controlled by an X10 Transceiver:

I have a little X10 transmitter attached to the serial port of the computer you see. It’s basically the setup from the Firecracker kit on X10.com. To check the status, we enabled the status widget feature of TeamCity, and I wrote a simple Ruby script to parse the widget using Why’s awesome Hpricot parser and the CM17A X10 Ruby code from Rubyforge. That script is available for download but is just:

require 'hpricot'
require 'open-uri'
require 'x10/cm17a'

def there_are_failing_builds()
  retry_count = 0
  begin
    doc = Hpricot(open("http://teamcity:8080/externalStatus.html"))
    failingBuildElements = doc.search("//img[@title='Build configuration is failing']")
    return (failingBuildElements.length > 0)
  rescue
    if retry_count < 3
      retry_count += 1
      puts "Network not available. Sleeping for 10 seconds then retrying"
      sleep 10 #Wait for a bit to see if the network will come up
      retry
    else
        puts "Could not open web page (Network is down?)"
        return false
    end
  end
end

def turn_on_lamp()
  puts "BUILD BROKEN! Turning On Lamp"
  #Do it twice because sometimes the first doesn't take
  X10.device('C1').on
  X10.device('C1').on
end

def turn_off_lamp()
  #Do it twice because sometimes the first doesn't take
  puts "Build A-Ok! Turning off lamp"
  X10.device('C1').off
  X10.device('C1').off
end

puts "Welcome to the Build Monitor"

while(true)
	if(there_are_failing_builds())
	  turn_on_lamp()
	else
	  turn_off_lamp()
	end
	puts "Next status check in 60 seconds..."
	sleep 60
end

We’ll also play a build break sound (the team has chose the Macarena for now), but sound isn’t working on that machine yet.

Happy hacking!