Subexec

by Peter Kieltyka http://github/nulayer/subexec

Subexec is a simple library that spawns an external command with an optional timeout parameter. It relies on Ruby 1.9's Process.spawn method. Also, it works with synchronous and asynchronous code.

Useful for libraries that are Ruby wrappers for CLI's. For example, resizing images with ImageMagick's mogrify command sometimes stalls and never returns control back to the original process. Enter Subexec.

Tested with MRI 1.9.3, 1.9.2, 1.8.7

Note: Process.spawn seems to be broken with JRuby 1.7.0.dev (as of April 20th, 2012), and so it uses Process.exec instead.

sub = Subexec.run "echo 'hello' && sleep 3", :timeout => 5
puts sub.output     # returns: hello
puts sub.exitstatus # returns: 0

sub = Subexec.run "echo 'hello' && sleep 3", :timeout => 1
puts sub.output     # returns: 
puts sub.exitstatus # returns:`

Only Ruby 1.9 can spawn non-blocking subprocesses, via Process.spawn. So Ruby 1.8 support is sheerly for backwards compatibility.

Limited Windows support is available. We are more than happy to accept patches. However, our tests are run on Unix-like operating systems. Primarily, the intended effect should be that Subexec works on Windows, though it may not give many advantages.