Gather the value of a Riemann metric for each node in PupppetDB

riemann-query-each-node.rb

#!/opt/puppetlabs/puppet/bin/ruby
# Gather the value of a Riemann metric for each node in PupppetDB

require 'optparse'

require 'puppetdb'
require 'riemann'

usage = "usage: #{$PROGRAM_NAME} [metric]"

OptionParser.new do |opts|
  opts.banner = usage
end.parse!

if ARGV.size > 1
  warn usage
  exit 1
end

service = ARGV[0] || "cpu"

pdb = PuppetDB::Client.new({:server => 'http://localhost:8079'})
r = Riemann::Client.new(:ssl => true, :key_file => '/etc/riemann/riemann.pkcs8', :cert_file => '/etc/riemann/riemann.crt', :ca_file => '/etc/riemann/ca.crt', :ssl_verify => true)

hosts = pdb.request('', 'nodes[certname] {}').data.map { |x| x['certname'] }
w = hosts.map { |host| host.length }.max

hosts.map! do |host|
  res = r.tcp["host = \"#{host}\" and service = \"#{service}\""]
  value = res.size == 1 ? res.first.metric : nil

  [host, value]
end

Hash[hosts].sort_by { |host, value| value || Float::INFINITY }.each do |host, value|
  puts(format("%-#{w}s %s\n", host, value ? format('%1.3f', value) : 'n/a'))
end