check-web-apps

#!/usr/bin/env ruby
require File.expand_path(File.dirname(__FILE__) + '/shared')
require 'uri'
require 'net/http'
require 'net/https'

def check(web_app)
	attempts = 0
	begin
		response = http_get(web_app['url'], web_app['username'], web_app['password'])
	rescue SocketError => e
		if attempts < 3
			attempts += 1
			sleep 1
			retry
		else
			notify_down(web_app, e)
			response = nil
		end
	rescue Errno::ECONNREFUSED, Errno::ECONNRESET, Errno::ETIMEDOUT, Timeout::Error => e
		notify_down(web_app, e)
		response = nil
	end
	if response && !response.body.include?(web_app['substring'])
		notify_down(web_app)
	end
rescue => e
	STDERR.puts "An exception occurred while checking for #{web_app['url']}"
	raise e
end

def notify_down(web_app, exception = nil)
	domain = URI.parse(web_app['url']).host
	message = "A web application is down!\n"
	if exception
		message << "Exception: #{exception}\n"
	end
	message << "URL: #{web_app['url']}\n"
	email(config(:from), config(:to),
		sprintf("#{config(:subject)}", domain),
		message)
end

def http_get(url, username = nil, password = nil)
	headers = {}
	uri = URI.parse(url)
	http = Net::HTTP.new(uri.host, uri.port)
	if uri.scheme == 'https'
		http.use_ssl = true
		http.verify_mode = OpenSSL::SSL::VERIFY_NONE
	end
	http.start do
		req = Net::HTTP::Get.new(uri.path, headers)
		req.basic_auth(username, password) if username
		http.request(req)
	end
end

def start
	config(:web_apps).each do |web_app|
		check(web_app)
	end
end

start