wrapping flightquest simulator

meryl.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-
require 'webrick'
require 'logger'

# Requirements:
#   * ruby >= 2
#   * mono
#   * FlightQuest Simulator

# Usage:
#   $ curl "localhost:3000/api?cruise39000_desc160_speed490_sample.csv"

RUN_SIMULATOR_CMD = "/usr/bin/mono /opt/GEFlight2/Rev3/FlightQuestSimulatorExecutable/RunSimulation.exe"
SUBMISSION_DIRNAME = "/opt/GEFlight2/Rev2/OneDaySimulatorFiles"


module Meryl
  class SimulatorRunner
    def initialize(cmd)
      @cmd = cmd
      @pid = nil
      @reader = nil
      @writer = nil
      @log = Logger.new(STDOUT)
    end

    def spawn
      out_r, out_w = IO.pipe
      in_r, in_w = IO.pipe

      @writer = in_w
      @reader = out_r
      @pid = Process.spawn(@cmd, :in => in_r, :out => out_w)
    end

    def prepare
      while ret = @reader.readline
        @log.info("RunSimulation: #{ret.rstrip}")
        break if ret =~ /Enter routes file name from/
      end
    end

    def run(filename)
      @writer.puts filename
      @writer.flush

      output = []
      while ret = @reader.readline
        @log.info("RunSimulation: #{ret.rstrip}")
        break if ret =~ /Enter routes file name from/
        output << ret
      end

      output.join("").rstrip
    end

    def shutdown
      @log.info("RunSimulation: going to shutdown")
      puts "going to shutdown"
      @writer.close
      @reader.close
      Process.waitpid(@pid)
      @log.info("RunSimulation: done")
    end
  end

  def self.start(cmd, dirname)
    wrapper = SimulatorRunner.new(cmd)
    wrapper.spawn
    wrapper.prepare

    server = WEBrick::HTTPServer.new(
      :Port => 3000,
      :BindAddress => '0.0.0.0',
    )

    server.mount_proc '/api' do |req, res|
      res.content_type = "text/plain"
      if File.exist?("#{dirname}/#{req.query_string}")
        res.body = wrapper.run(req.query_string)
      else
        res.body = "requested file not found"
      end
    end

    trap 'INT' do
      server.shutdown
      wrapper.shutdown
    end
    server.start
  end
end

Meryl.start(RUN_SIMULATOR_CMD, SUBMISSION_DIRNAME)