gistfile1.rb

require 'net/http'

# Query external DB to fetch latest ssh known hosts, and store locally for 1 hour.
module Puppet::Parser::Functions
 newfunction(:sshkeyfromdb, :type => :rvalue) do |args|
  #local cache file on each puppetmaster
  ssh_keys_file = "/tmp/sshkeys"
  #URL to query
  host = "puppet"
  url = "/setting/ssh_keys"
  #Time to keep cache - e.g. 1 hours.
  ttl = (60 * 60)

  # create a cache file
  unless File.exist?(ssh_keys_file) or File.mtime(ssh_keys_file) > (Time.now - ttl)
  # cache miss, refreshing
    keys = Net::HTTP.get host,url
    File.new(ssh_keys_file,"w", 0600).write(keys)
  else
    keys = File.open(ssh_keys_file).read
  end
  return keys
 end
end