mirror of
https://codeberg.org/redict/redict.git
synced 2025-01-24 00:59:02 -05:00
73 lines
1.6 KiB
Ruby
73 lines
1.6 KiB
Ruby
require 'digest/md5'
|
|
class HashRing
|
|
attr_reader :ring, :sorted_keys, :replicas, :nodes
|
|
# nodes is a list of objects that have a proper to_s representation.
|
|
# replicas indicates how many virtual points should be used pr. node,
|
|
# replicas are required to improve the distribution.
|
|
def initialize(nodes=[], replicas=3)
|
|
@replicas = replicas
|
|
@ring = {}
|
|
@nodes = []
|
|
@sorted_keys = []
|
|
nodes.each do |node|
|
|
add_node(node)
|
|
end
|
|
end
|
|
|
|
# Adds a `node` to the hash ring (including a number of replicas).
|
|
def add_node(node)
|
|
@nodes << node
|
|
@replicas.times do |i|
|
|
key = gen_key("#{node}:#{i}")
|
|
@ring[key] = node
|
|
@sorted_keys << key
|
|
end
|
|
@sorted_keys.sort!
|
|
end
|
|
|
|
def remove_node(node)
|
|
@replicas.times do |i|
|
|
key = gen_key("#{node}:#{count}")
|
|
@ring.delete(key)
|
|
@sorted_keys.reject! {|k| k == key}
|
|
end
|
|
end
|
|
|
|
# get the node in the hash ring for this key
|
|
def get_node(key)
|
|
get_node_pos(key)[0]
|
|
end
|
|
|
|
def get_node_pos(key)
|
|
return [nil,nil] if @ring.size == 0
|
|
key = gen_key(key)
|
|
nodes = @sorted_keys
|
|
nodes.size.times do |i|
|
|
node = nodes[i]
|
|
if key <= node
|
|
return [@ring[node], i]
|
|
end
|
|
end
|
|
[@ring[nodes[0]], 0]
|
|
end
|
|
|
|
def iter_nodes(key)
|
|
return [nil,nil] if @ring.size == 0
|
|
node, pos = get_node_pos(key)
|
|
@sorted_keys[pos..-1].each do |k|
|
|
yield @ring[k]
|
|
end
|
|
end
|
|
|
|
def gen_key(key)
|
|
key = Digest::MD5.hexdigest(key)
|
|
((key[3] << 24) | (key[2] << 16) | (key[1] << 8) | key[0])
|
|
end
|
|
|
|
end
|
|
|
|
# ring = HashRing.new ['server1', 'server2', 'server3']
|
|
# p ring
|
|
# #
|
|
# p ring.get_node "kjhjkjlkjlkkh"
|
|
# |