container

#!/usr/bin/ruby

require 'optparse'
require 'time'
require 'json'

OPTIONS = {:action => nil, :inspect => false, :save_state => nil, :metadata => nil}
METHODS = %w{START UPDATE VALIDATE}
ENVVARS = %w{BUILD_CAUSE BUILD_TIME BUILD_MONTH BUILD_WEEK BUILD_DAY BUILD_HASH BUILD_TAG}

opt = OptionParser.new

opt.banner = "Start, stop and validate containers"
opt.separator ""

["START", "UPDATE", "VALIDATE"].each do |method|
  option = "--%s" % method.downcase
  help = "Perform the %s action based on %s_METHOD" % [method.downcase, method]

  opt.on(option, help) do
    OPTIONS[:action] = method
  end
end

opt.on("--inspect", "Show image metadata") do
  OPTIONS[:inspect] = true
end

opt.on("--metadata", "Show JSON metadata for image") do
  OPTIONS[:metadata] = true
end

opt.parse!

def self.color(code)
  colors = {:red => "",
    :green => "",
    :yellow => "",
    :cyan => "",
    :bold => "",
    :reset => ""}

  if STDOUT.tty?
    return colors[code] || ""
  else
    return ""
  end
end

def self.colorize(code, msg)
  "%s%s%s" % [ color(code), msg, color(:reset) ]
end

def valid_method?(method)
  METHODS.include?(method)
end

def key_for_method(method)
  "%s_METHOD" % method.upcase
end

def validate_method_script(method)
  return unless script_for(method)

  File.exist?(script_for(method)) && File.executable?(script_for(method))
end

def script_for(method)
  key = key_for_method(method)

  image_metadata[key.downcase] || ENV[key]
end

def method_supported?(method)
  key = key_for_method(method)

  image_metadata[key.downcase] || ENV[key]
end

def images_metadata
  Dir.entries("/").grep(/^\.image_metadata/).map do |metadata|
    if metadata =~ /^\.image_metadata_(.+)/
      [$1, JSON.parse(File.read(File.join("/", metadata)))]
    else
      [nil, {}]
    end
  end.sort_by{|_, m| m["build_time_stamp"]}.map {|i, m| [i, m]}
end

def image_metadata
  images_metadata.last[1]
end

def inspect_container
  if ENV["CONTAINER_FIRST_START"]
    puts "Container first started at %s (%s)" % [colorize(:bold, Time.at(Integer(ENV["CONTAINER_FIRST_START"]))), ENV["CONTAINER_FIRST_START"]]
    puts
  end

  puts "Container management methods:"
  puts

  METHODS.each do |method|
    if script = script_for(method)
      if File.exist?(script) && File.executable?(script)
        puts colorize(:green, "   Container supports %s method using command %s" % [method, script])
      else
        puts colorize(:red,   "   Container supports %s method but %s does not exist or is not executable" % [method, script])
      end
    else
      puts colorize(:yellow, "   Container does not support the %s method" % method)
    end
  end

  images_metadata.each do |image, metadata|
    next unless image

    puts
    puts "Metadata for image %s" % colorize(:bold, image)

    puts
    puts "  Names:"
    puts "            Project Name: %s " % metadata["project"]
    puts "              Image Name: %s " % metadata["image_name"]
    puts "         Image Tag Names: %s " % metadata["image_tag_names"].join(", ")
    puts
    puts "  Build Info:"
    puts "                  CI Run: %s " % metadata["ci"]
    puts "                Git Hash: %s " % metadata["gitref"]
    puts "             Build Cause: %s " % metadata["build_cause"]
    puts "              Build Time: %s (%s) " % [metadata["build_time"], metadata["build_time_stamp"]]
    puts "               Build Tag: %s " % metadata["build_tag"]
    puts
    puts "  Actions:"
    puts "                   START: %s " % [metadata["start_method"] || colorize(:yellow, "not set")]
    puts "                  UPDATE: %s " % [metadata["update_method"] || colorize(:yellow, "not set")]
    puts "                VALIDATE: %s " % [metadata["validate_method"] || colorize(:yellow, "not set")]
  end
end

def set_environment_for(method)
  ENV["CONTAINER_RUN_MODE"] = method
end

def run_method(method)
  abort("Unknown method %s" % method) unless valid_method?(method)
  abort("This container does not support the %s method" % method) unless method_supported?(method)
  abort("The script %s does not exist or is not executable" % script_for(method)) unless validate_method_script(method)

  if script = script_for(OPTIONS[:action])
    puts "%s: Performing %s action via %s" % [Time.now, colorize(:bold, method), colorize(:bold, script)]
    set_environment_for(method)
    exec(script)
  else
    abort("%s environment variable is not set, cannot perform %s action" % [key_for_method(method), method])
  end
end

def metadata
  puts image_metadata.to_json
end

if OPTIONS[:inspect]
  inspect_container
elsif OPTIONS[:metadata]
  metadata
elsif OPTIONS[:action]
  run_method(OPTIONS[:action])
else
  puts opt
  exit 1
end