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Subexec

# Subexec

## Description

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. Subexec executes mogrify and preempts if it gets lost.

## Usage

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

# Timeout process after a second sub = Subexec.run "echo 'hello' && sleep 3", :timeout => 1 puts sub.output # returns: puts sub.exitstatus # returns:

Constants

VERSION

Attributes

command[RW]
exitstatus[RW]
lang[RW]
log_file[RW]
output[RW]
pid[RW]
timeout[RW]

Public Class Methods

new(command, options={}) click to toggle source 
# File lib/subexec.rb, line 45
def initialize(command, options={})
  self.command    = command
  self.lang       = options[:lang]      || "C"
  self.timeout    = options[:timeout]   || -1     # default is to never timeout
  self.log_file   = options[:log_file]
  self.exitstatus = 0
end
run(command, options={}) click to toggle source 
# File lib/subexec.rb, line 39
def self.run(command, options={})
  sub = new(command, options)
  sub.run!
  sub
end

Public Instance Methods

run!() click to toggle source 
# File lib/subexec.rb, line 53
def run!
  if RUBY_VERSION >= '1.9' && RUBY_ENGINE != 'jruby'
    spawn
  else
    exec
  end
end

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