A sensu mutator to turn warnings into criticals when the TTL has expired.

ttl_warn_to_crit.rb

#!/usr/bin/env ruby
#
# Mutate TTL results with warnings to critical status
# Because Sensu hardcodes a stale TTL check to status=1
#   we'll never get paged for TTL failures.
# Refer to https://github.com/sensu/sensu/issues/1166
#
# Cribbed from the example at https://sensuapp.org/docs/0.25/reference/plugins.html#example-plugins

require 'json'

event = JSON.parse(STDIN.read, :symbolize_names => true)

# If we have a check with a ttl and a warning status
# check if the time since execution is more than the allowed TTL
# Change the status to 2 if so.
if (event[:check].key?(:ttl) && event[:check][:status] == 1)
  time_since_last_execution = Time.now.to_i - event[:check][:executed]
  if time_since_last_execution >= event[:check][:ttl]
    event[:check][:status] = 2
  end
end

puts event.to_json