A consistent hashing implementation in ruby

consistent_hashing.rb

require 'digest'

class ConsistentHashing
  def initialize(nodes)
    nodes.map { |node| add_node(node) }
  end

  def find_cache(key)
    puts
    hash = hash_value(key)
    puts "#{key} hashes to #{hash}"

    node_hash = closest_node_hash(hash)
    node = hash_to_node[node_hash]

    puts "#{key} maps to  #{node}"
  end

  def add_node(node)
    hash = hash_value(node)
    hash_to_node[hash] = node

    puts "Nodes map to #{@hash_to_node}"
  end

  def remove_node(node)
    hash = hash_value(node)
    @hash_to_node = @hash_to_node.select{|node| node != hash}

    puts "Nodes map to #{@hash_to_node}"
  end

  private

  def hash_value(key)
    Digest::SHA256.digest(key).sum % 360
  end

  def hash_to_node
    @hash_to_node ||= {}
  end

  def closest_node_hash(key)
    @hash_to_node.keys.sort.bsearch { |server| server >= key } || @hash_to_node.keys.sort.first
  end
end

servers = ["server:A", "server:B", "server:C"]

hasher = ConsistentHashing.new(servers)

hasher.find_cache("a")
hasher.find_cache("b")
hasher.find_cache("z")
hasher.find_cache("hello")

hasher.add_node("server:B1")
hasher.find_cache("a")
hasher.find_cache("b")
hasher.find_cache("z")
hasher.find_cache("hello")

hasher.remove_node("server:B")
hasher.find_cache("a")
hasher.find_cache("b")
hasher.find_cache("z")
hasher.find_cache("hello")