Breaking out from threaded loop

Question

I'm downloading images from a (descending) time ordered gallery. I want to stop, when we get to the pictures already down.

require 'thread/pool'

def getimg(uri)
#...
  if File.exist? filename
    raise "Already done."  # something like this
  end
#...
end

pool = Thread.pool(4)

thumbs.each do |a|
  pool.process {
    getimg(URI(a.attr('href')))
  }
end

Answer 1

How about passing a pool object and use pool.shutdown?

require 'thread/pool'

def getimg(uri, pool) # <----
#...
  if File.exist? filename
    pool.shutdown  # <--------
    return         # <------
  end
#...
end

pool = Thread.pool(4)

thumbs.each do |a|
  pool.process {
    getimg(URI(a.attr('href')), pool) # <----
  }
end

According to the Thread::Pool#process code comment:

Shut down the pool, it will block until all tasks have finished running.

UPDATE

use shutdown! instead of shutdown.

shutown! Shut down the pool instantly without finishing to execute tasks.