module Timeout

Timeout long-running blocks

Synopsis

require 'timeout'
status = Timeout::timeout(5) {
  # Something that should be interrupted if it takes more than 5 seconds...
}

Description

Timeout provides a way to auto-terminate a potentially long-running operation if it hasn't finished in a fixed amount of time.

Previous versions didn't use a module for namespacing, however timeout is provided for backwards compatibility. You should prefer #timeout instead.

Copyright

Copyright: (C) 2000 Network Applied Communication Laboratory, Inc.
Copyright: (C) 2000 Information-technology Promotion Agency, Japan

Constants

ExitException: Raised by #timeout when the block times out.

Public Class Methods

timeout(sec, klass = nil) { |sec| ... } Show source

# File lib/timeout.rb, line 72
def timeout(sec, klass = nil)   #:yield: +sec+
  return yield(sec) if sec == nil or sec.zero?
  message = "execution expired"
  e = Error
  bl = proc do |exception|
    begin
      x = Thread.current
      y = Thread.start {
        begin
          sleep sec
        rescue => e
          x.raise e
        else
          x.raise exception, message
        end
      }
      return yield(sec)
    ensure
      if y
        y.kill
        y.join # make sure y is dead.
      end
    end
  end
  if klass
    begin
      bl.call(klass)
    rescue klass => e
      bt = e.backtrace
    end
  else
    bt = Error.catch(message, &bl)
  end
  rej = /\A#{Regexp.quote(__FILE__)}:#{__LINE__-4}\z/o
  bt.reject! {|m| rej =~ m}
  level = -caller(CALLER_OFFSET).size
  while THIS_FILE =~ bt[level]
    bt.delete_at(level)
  end
  raise(e, message, bt)
end

Perform an operation in a block, raising an error if it takes longer than sec seconds to complete.

sec: Number of seconds to wait for the block to terminate. Any number may be used, including Floats to specify fractional seconds. A value of 0 or nil will execute the block without any timeout.
klass: Exception Class to raise if the block fails to terminate in sec seconds. Omitting will use the default, Timeout::Error

Returns the result of the block if the block completed before sec seconds, otherwise throws an exception, based on the value of klass.

The exception thrown to terminate the given block cannot be rescued inside the block unless klass is given explicitly.

Note that this is both a method of module Timeout, so you can include Timeout into your classes so they have a timeout method, as well as a module method, so you can call it directly as #timeout.

Private Instance Methods