#!/usr/bin/env ruby
require 'json'
require 'thread'
require 'logger'

require 'bunny'
require 'trollop'
require 'franz'


# If we find a local config, try to use it
# N.B. We'll fall back to the last guy listed here
config = nil
%w[
  config.json
  %{HOME}/.franz.json
  /etc/franz/franz.json
].each do |path|
  config = path % ENV rescue next
  break if File.exist? config
end


# Franz really only accepts a config file as an option, and that config file
# has got to conform to a certain format. If you're unsure, just look at the
# default options hashes in both Franz::Input and Franz::Output
opts = Trollop::options(ARGV) do
  version Franz::VERSION
  banner Franz::ART + "\n\n" + <<-EOS.gsub(/^    /, '')
    #{Franz::SUMMARY}

    Usage: franz [<options>]

    Options:
  EOS
  opt :config, 'Configuration file to use', type: :string, default: config
  opt :debug,  'Enable debugging output', default: false
  opt :trace,  'Enable trace output', default: false
  opt :log,    'Log to file, not STDOUT', type: :string, default: nil
end

Thread.abort_on_exception = true # Die quickly and with great ceremony

config = Franz::Config.new opts[:config]
logger = Franz::Logger.new opts[:debug], opts[:trace], opts[:log]

io_bound = config[:output][:bound] || 10_000
io = SizedQueue.new io_bound

# Now we'll connect to our output, RabbitMQ. This creates a new thread in the
# background, which will consume the events generated by our input on io
Franz::Output.new \
  input: io,
  output: config[:output][:rabbitmq],
  logger: logger,
  tags: config[:output][:tags]

# Franz has only one kind of input, plain text files.
Franz::Input.new \
  input: config[:input],
  output: io,
  logger: logger,
  checkpoint: config[:checkpoint],
  checkpoint_interval: config[:checkpoint_interval]

# Ensure memory doesn't grow too large (> 1GB by default)
def mem_kb ; `ps -o rss= -p #{$$}`.strip.to_i ; end

mem_limit = config[:memory_limit] || 1_000_000
mem_sleep = config[:memory_limit_interval] || 60

loop do
  sleep mem_sleep
  mem_used = mem_kb
  if mem_used > mem_limit
    logger.fatal \
      event: 'killed',
      reason: 'Consuming too much memory',
      used: mem_used,
      limit: mem_limit
    exit(1)
  end
  logger.debug \
    event: 'memcheck',
    used: mem_used,
    limit: mem_limit
end