A reentrant/recursive flock.

Add this line to your application's Gemfile:

gem 'reentrant_flock'

And then execute:

$ bundle

Or install it yourself as:

$ gem install reentrant_flock

require 'reentrant_flock'

File.open('/tmp/lock', File::RDWR | File::CREAT) do |fp|
  ReentrantFlock.synchronize(fp, File::LOCK_EX) do
    ReentrantFlock.synchronize(fp, File::LOCK_EX) do
      # Not blocked by myself
    end
  end
end

require 'reentrant_flock'

def with_rlock(&block)
  File.open('/tmp/lock', File::RDWR | File::CREAT) do |fp|
    ReentrantFlock.synchronize(fp, File::LOCK_EX, &block)
  end
end

with_rlock do
  with_rlock do
    # Not blocked by myself
  end
end

ReentrantFlock.synchronize would raise ReentrantFlock::AlreadyLocked if File::LOCK_NB is given and already locked by somebody else.

See File#flock for flags.

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/sonots/reentrant_flock.