Method: Spring::Application#serve

Defined in:

lib/spring/application.rb

#serve(client) ⇒ Object

# File 'lib/spring/application.rb', line 169

def serve(client)
  log "got client"
  manager.puts

  @clients[client] = true

  _stdout, stderr, _stdin = streams = 3.times.map { client.recv_io }
  [STDOUT, STDERR, STDIN].zip(streams).each { |a, b| a.reopen(b) }

  if preloaded?
    client.puts(0) # preload success
  else
    begin
      preload
      client.puts(0) # preload success
    rescue Exception
      log "preload failed"
      client.puts(1) # preload failure
      raise
    end
  end

  args, env = JSON.load(client.read(client.gets.to_i)).values_at("args", "env")
  command   = Spring.command(args.shift)

  connect_database
  setup command

  if Rails.application.reloaders.any?(&:updated?)
    Rails.application.reloader.reload!
  end

  pid = fork {
    # Make sure to close other clients otherwise their graceful termination
    # will be impossible due to reference from this fork.
    @clients.each_key { |c| c.close if c != client }

    Process.setsid
    IGNORE_SIGNALS.each { |sig| trap(sig, "DEFAULT") }
    trap("TERM", "DEFAULT")

    unless Spring.quiet
      STDERR.puts "Running via Spring preloader in process #{Process.pid}"

      if Rails.env.production?
        STDERR.puts "WARNING: Spring is running in production. To fix "         \
                    "this make sure the spring gem is only present "            \
                    "in `development` and `test` groups in your Gemfile "       \
                    "and make sure you always use "                             \
                    "`bundle install --without development test` in production"
      end
    end

    ARGV.replace(args)
    $0 = command.exec_name

    # Delete all env vars which are unchanged from before Spring started
    original_env.each { |k, v| ENV.delete k if ENV[k] == v }

    # Load in the current env vars, except those which *were* changed when Spring started
    env.each { |k, v| ENV[k] ||= v }

    connect_database
    srand

    invoke_after_fork_callbacks
    shush_backtraces

    command.call
  }

  disconnect_database

  log "forked #{pid}"
  manager.puts pid

  wait pid, streams, client
rescue Exception => e
  log "exception: #{e}"
  manager.puts unless pid

  if streams && !e.is_a?(SystemExit)
    print_exception(stderr, e)
    streams.each(&:close)
  end

  client.puts(1) if pid
  client.close
ensure
  # Redirect STDOUT and STDERR to prevent from keeping the original FDs
  # (i.e. to prevent `spring rake -T | grep db` from hanging forever),
  # even when exception is raised before forking (i.e. preloading).
  reset_streams
end