This is an implementation of the Chord protocol, a description of which can be found here: http://pdos.csail.mit.edu/chord/papers/chord.pdf http://pdos.csail.mit.edu/chord/papers/paper-ton.pdf http://en.wikipedia.org/wiki/Chord_%28peer-to-peer%29
The implementation is based on the psuedocode and implementation suggestions in the MIT papers, but it has some modifications.
As it stands currently, nodes can balance their workload with their successor. It currently does this by comparing its workload to the load of the successor. If the successor has a sufficiently larger load, as determined by the Swiftcore::Chord::Node#calculate_allowable_difference method, then the node will advance its ID, and thus, the keyspace that it is responsible for, towards that of its successor. It then tells its successor to reallocate data that lies in the new keyspace to it.
By only moving towards a successor, without ever changing relative positions, changing a node's id/keyspace coverage doesn't harm the ability of the the chord to find the data in any given node, and the balancing algorithm will eventually result in well distributed nodes, even as data changes and nodes are added or removed from the chord.
Add this line to your application's Gemfile:
gem 'chord'And then execute:
$ bundle
Or install it yourself as:
$ gem install chord
TODO: Write usage instructions here
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/wyhaines/chord. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
The gem is available as open source under the terms of the MIT License.