class Rack::Reloader

High performant source reloader

This class acts as Rack middleware.

What makes it especially suited for use in a production environment is that any file will only be checked once and there will only be made one system call stat(2).

Please note that this will not reload files in the background, it does so only when actively called.

It is performing a check/reload cycle at the start of every request, but also respects a cool down time, during which nothing will be done.

Public Class Methods

new (app, cooldown = 10, backend = Stat)

# File lib/rack/reloader.rb, line 25
def initialize(app, cooldown = 10, backend = Stat)
  @app = app
  @cooldown = cooldown
  @last = (Time.now - cooldown)
  @cache = {}
  @mtimes = {}
  @reload_mutex = Mutex.new

  extend backend
end

Public Instance Methods

call (env)

# File lib/rack/reloader.rb, line 36
def call(env)
  if @cooldown and Time.now > @last + @cooldown
    if Thread.list.size > 1
      @reload_mutex.synchronize{ reload! }
    else
      reload!
    end

    @last = Time.now
  end

  @app.call(env)
end

reload! (stderr = $stderr)

# File lib/rack/reloader.rb, line 50
def reload!(stderr = $stderr)
  rotation do |file, mtime|
    previous_mtime = @mtimes[file] ||= mtime
    safe_load(file, mtime, stderr) if mtime > previous_mtime
  end
end

safe_load (file, mtime, stderr = $stderr)

A safe Kernel::load, issuing the hooks depending on the results

# File lib/rack/reloader.rb, line 58
def safe_load(file, mtime, stderr = $stderr)
  load(file)
  stderr.puts "#{self.class}: reloaded `#{file}'"
  file
rescue LoadError, SyntaxError => ex
  stderr.puts ex
ensure
  @mtimes[file] = mtime
end