Forkoff-0.0.4

NAME

forkoff

SYNOPSIS

brain-dead simple parallel processing for ruby

URI

http://rubyforge.org/projects/codeforpeople

INSTALL

gem install forkoff

DESCRIPTION

forkoff works for any enumerable object, iterating a code block to
run in a
child process and collecting the results. forkoff can limit the
number of
child processes which is, by default, 2.

HISTORY
0.0.4
- code re-org
- add :strategy option
- default number of processes is 2, not 8

SAMPLES

<========< samples/a.rb >========>

~ > cat samples/a.rb

 # forkoff makes it trivial to do parallel processing with ruby,

the following
# prints out each word in a separate process
#

   require 'forkoff'

   %w( hey you ).forkoff!{|word| puts "#{ word } from

#{ Process.pid }"}

~ > ruby samples/a.rb

 hey from 1032
 you from 1033

<========< samples/b.rb >========>

~ > cat samples/b.rb

 # for example, this takes only 4 seconds or so to complete (8

iterations
# running in two processes = twice as fast)
#

   require 'forkoff'

   a = Time.now.to_f

   results =
     (0..7).forkoff do |i|
       sleep 1
       i ** 2
     end

   b = Time.now.to_f

   elapsed = b - a

   puts "elapsed: #{ elapsed }"
   puts "results: #{ results.inspect }"

~ > ruby samples/b.rb

 elapsed: 4.25545883178711
 results: [0, 1, 4, 9, 16, 25, 36, 49]

<========< samples/c.rb >========>

~ > cat samples/c.rb

 # forkoff does *NOT* spawn processes in batches, waiting for each

batch to
# complete. rather, it keeps a certain number of processes busy
until all
# results have been gathered. in otherwords the following will
ensure that 3
# processes are running at all times, until the list is complete.
note that
# the following will take about 3 seconds to run (3 sets of 3 @ 1
second).
#

 require 'forkoff'

 pid = Process.pid

 a = Time.now.to_f

 pstrees =
   %w( a b c d e f g h i ).forkoff! :processes => 3 do |letter|
     sleep 1
     { letter => ` pstree -l 2 #{ pid } ` }
   end


 b = Time.now.to_f

 puts
 puts "pid: #{ pid }"
 puts "elapsed: #{ b - a }"
 puts

 require 'yaml'

 pstrees.each do |pstree|
   y pstree
 end

~ > ruby samples/c.rb

 pid: 1048
 elapsed: 3.14415812492371

 ---
 a: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01049 ahoward ruby -Ilib samples/c.rb
    |-+- 01050 ahoward ruby -Ilib samples/c.rb
    \-+- 01051 ahoward ruby -Ilib samples/c.rb

 ---
 b: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01049 ahoward (ruby)
    |-+- 01050 ahoward ruby -Ilib samples/c.rb
    \-+- 01051 ahoward ruby -Ilib samples/c.rb

 ---
 c: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01049 ahoward ruby -Ilib samples/c.rb
    |-+- 01050 ahoward ruby -Ilib samples/c.rb
    \-+- 01051 ahoward ruby -Ilib samples/c.rb

 ---
 d: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01061 ahoward ruby -Ilib samples/c.rb
    |-+- 01062 ahoward ruby -Ilib samples/c.rb
    \-+- 01063 ahoward ruby -Ilib samples/c.rb

 ---
 e: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01061 ahoward (ruby)
    |-+- 01062 ahoward ruby -Ilib samples/c.rb
    \-+- 01063 ahoward ruby -Ilib samples/c.rb

 ---
 f: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01061 ahoward ruby -Ilib samples/c.rb
    |-+- 01062 ahoward ruby -Ilib samples/c.rb
    \-+- 01063 ahoward ruby -Ilib samples/c.rb

 ---
 g: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01090 ahoward ruby -Ilib samples/c.rb
    |-+- 01091 ahoward ruby -Ilib samples/c.rb
    \-+- 01092 ahoward ruby -Ilib samples/c.rb

 ---
 h: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01090 ahoward ruby -Ilib samples/c.rb
    |-+- 01091 ahoward ruby -Ilib samples/c.rb
    \-+- 01092 ahoward ruby -Ilib samples/c.rb

 ---
 i: |
   -+- 01048 ahoward ruby -Ilib samples/c.rb
    |-+- 01090 ahoward ruby -Ilib samples/c.rb
    |-+- 01091 ahoward ruby -Ilib samples/c.rb
    \-+- 01092 ahoward ruby -Ilib samples/c.rb

<========< samples/d.rb >========>

~ > cat samples/d.rb

 # forkoff supports two strategies of reading the result from the

child: via
# pipe (the default) or via file. you can select which to use
using the
# :strategy option.
#

   require 'forkoff'

   %w( hey you guys ).forkoff :strategy => :file do |word|
     puts "#{ word } from #{ Process.pid }"
   end

~ > ruby samples/d.rb

 hey from 1102
 you from 1103
 guys from 1104

a @ http://codeforpeople.com/