Simple rake progress bar

gistfile1.txt

# Use:
#
# # Pass an emuerable to #new
#
# users = User.active
# RakeProgrssBar.new(users) do |user|
#   user.do_something_amazing
# end
#
#
# # Or, pass any iterator to #new; ie, each_with_index
#
# users = User.active
# RakeProgressBar.new(users.each_with_index) do |user,index|
#   user.something_else_awesome
# end
#
#
# # Or, store progress_bar and iterate with #each later
#
# progress_bar = RakeProgressBar.new(users.active)
#
# progress_bar.each do |user|
#   user.something_else_again
# end
#
#
# As always, use CTRL-C to abort
#
class RakeProgressBar

  attr_reader :iterator, :count, :width

  def initialize(iterator, options = {}, &block)
    @iterator = iterator
    @count = options[:count] || iterator.count
    @width = options[:width] || 70 # TODO figure out console width

    each(&block) if block_given?
  end

  def each
    print "\n"
    time_start = Time.now

    index = 0
    iterator.each do |*args|

      index += 1
      progress = ((index.to_f / count) * width).to_i


      elapsed = Time.now - time_start
      remaining = (elapsed.to_f / index) * count - index

      print "Elapsed: #{format_time elapsed} | Remaining: #{format_time remaining}\n"
      print "[#{'#' * progress}#{'-' * (width - progress)}]"
      print "(#{index} / #{count})"
      yield *args
      cursor_up
    end
    print "\n"
  end

  def cursor_up
    print "\r" # move to beginning of current line
    print "\e[0k" # clear line
    print "\e[0A" # move up to previous line
    print "\e[0k" # clear line
  end

  def format_time(time)
    # TODO Fails if `time` is more than 24 hours...
    Time.at(time).gmtime.strftime('%H:%M:%S')
  end
end


=begin
require './lib/rake_progress_bar'

desc "Test the RakeProgressBar thingy"
task :test_progress_bar do
  puts "Looping 1000 times with a .1 second delay"
  RakeProgressBar.new((1..1000).each_with_index).each do |i|
    sleep 0.1
    # nothing
  end
  puts "Done!"
end
=end