A Ruby utility script for use in `git bisect`. Returns a non-0 exit code if memory usage for the process exceeds a specified number.

memory_usage.rb

# To run git bisect looking for the first spec suite to exceed 1000MB of RAM:
# git bisect run ruby memory_usage.rb 'rake spec' 1000000

require 'open3'

command = ARGV[0]
threshold = ARGV[1].to_i || 500000

cmd = "/usr/bin/time -v #{command}"
Open3.popen3(cmd) do |stdin, stdout, stderr, wait_thr|
  output = stderr.read.gsub("\t", "")
  match = /Maximum resident set size \(kbytes\): (.*)/.match(output.strip)
  memory_usage = match[1].to_i
  p "Memory usage: #{memory_usage}KB"

  if memory_usage > threshold
    Process.exit 1
  else
    Process.exit 0
  end
end