Class: Rack::Reloader

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/reloader.rb

Overview

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.

Defined Under Namespace

Modules: Stat

Instance Method Summary collapse

Constructor Details

#initialize(app, cooldown = 10, backend = Stat) ⇒ Reloader

Returns a new instance of Reloader.


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# File 'lib/rack/reloader.rb', line 27

def initialize(app, cooldown = 10, backend = Stat)
  @app = app
  @cooldown = cooldown
  @last = (Time.now - cooldown)
  @cache = {}
  @mtimes = {}
  @reload_mutex = Mutex.new

  extend backend
end

Instance Method Details

#call(env) ⇒ Object


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# File 'lib/rack/reloader.rb', line 38

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) ⇒ Object


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# File 'lib/rack/reloader.rb', line 52

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) ⇒ Object

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


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# File 'lib/rack/reloader.rb', line 60

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