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102 lines
2.4 KiB
102 lines
2.4 KiB
local it = require "prosody.util.iterators";
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local function generate_ring(nodes, num_replicas, hash)
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local new_ring = {};
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for _, node_name in ipairs(nodes) do
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for replica = 1, num_replicas do
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local replica_hash = hash(node_name..":"..replica);
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new_ring[replica_hash] = node_name;
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table.insert(new_ring, replica_hash);
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end
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end
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table.sort(new_ring);
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return new_ring;
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end
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local hashring_methods = {};
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local hashring_mt = {
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__index = function (self, k)
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-- Automatically build self.ring if it's missing
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if k == "ring" then
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local ring = generate_ring(self.nodes, self.num_replicas, self.hash);
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rawset(self, "ring", ring);
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return ring;
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end
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return rawget(hashring_methods, k);
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end
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};
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local function new(num_replicas, hash_function)
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return setmetatable({ nodes = {}, num_replicas = num_replicas, hash = hash_function }, hashring_mt);
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end;
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function hashring_methods:add_node(name, value)
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self.ring = nil;
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self.nodes[name] = value == nil and true or value;
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table.insert(self.nodes, name);
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return true;
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end
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function hashring_methods:add_nodes(nodes)
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self.ring = nil;
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local iter = pairs;
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if nodes[1] then -- simple array?
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iter = it.values;
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end
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for node_name, node_value in iter(nodes) do
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if self.nodes[node_name] == nil then
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self.nodes[node_name] = node_value == nil and true or node_value;
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table.insert(self.nodes, node_name);
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end
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end
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return true;
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end
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function hashring_methods:remove_node(node_name)
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self.ring = nil;
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if self.nodes[node_name] ~= nil then
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for i, stored_node_name in ipairs(self.nodes) do
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if node_name == stored_node_name then
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self.nodes[node_name] = nil;
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table.remove(self.nodes, i);
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return true;
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end
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end
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end
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return false;
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end
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function hashring_methods:remove_nodes(nodes)
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self.ring = nil;
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for _, node_name in ipairs(nodes) do
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self:remove_node(node_name);
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end
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end
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function hashring_methods:clone()
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local clone_hashring = new(self.num_replicas, self.hash);
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for node_name, node_value in pairs(self.nodes) do
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clone_hashring.nodes[node_name] = node_value;
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end
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clone_hashring.ring = nil;
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return clone_hashring;
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end
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function hashring_methods:get_node(key)
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local node;
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local key_hash = self.hash(key);
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for _, replica_hash in ipairs(self.ring) do
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if key_hash < replica_hash then
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node = self.ring[replica_hash];
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break;
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end
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end
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if not node then
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node = self.ring[self.ring[1]];
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end
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return node, self.nodes[node];
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end
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return {
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new = new;
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}
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