consume_consul_events

#!/usr/bin/env ruby

# check if the bundle installed gems somewhere besides the system, and if it
# did manually add that path to the GEM_PATH. all without actually loading the
# bundle, because it's huge
require 'pathname'
expanded_path = Pathname.new(__FILE__).realpath
rails_root = File.expand_path("../..", expanded_path)
bundle_config_file = "#{rails_root}/.bundle/config"
if File.exist?(bundle_config_file)
  require 'yaml'
  bundle_config = YAML.load_file(bundle_config_file)
  if bundle_config['BUNDLE_PATH']
    bundle_gem_path = File.expand_path("#{bundle_config['BUNDLE_PATH']}/#{RUBY_ENGINE}/#{RbConfig::CONFIG['ruby_version']}", rails_root)
    Gem::Specification.dirs = (Array(Gem.path) + [bundle_gem_path]).uniq
  end
end

gem 'redis'

require 'base64'
require 'json'
require 'redis'

# this purposely has no config so that it can spin up quickly;
# just copy this script elsewhere and modify if you have a
# non-default configuration
cache = Redis.new

data = JSON.load(STDIN.read)
data.each do |event|
  id = event['ID']
  # only invalidate events we haven't seen yet
  if cache.zadd("consul_events", Time.now.utc.to_f, id, nx: true)
    key = Base64.decode64(event['Payload'])
    # Special-case flushall
    if key == 'FLUSHDB'
      cache.flushdb
      # Readd this event so that it doesn't get forgotten about in the future
      cache.zadd("consul_events", Time.now.utc.to_f, id, nx: true)
    else
      cache.del(key)
    end
  end
end
# limit the set to the 256 newest elements
cache.zremrangebyrank("consul_events", 0, -257)