Software /
code /
prosody
File
util/hashring.lua @ 13014:06453c564141
util.startup: Add prosody.started promise to easily execute code after startup
To avoid a race where server-started fires before the promise function body is
run (on next tick), I moved server-started to fire on the next tick, which
seems sensible anyway.
Errors are logged, I'm not sure if we ought to be doing something more here.
I'm sure we'll find out.
author | Matthew Wild <mwild1@gmail.com> |
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date | Sat, 01 Apr 2023 11:56:38 +0100 |
parent | 12975:d10957394a3c |
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local it = require "prosody.util.iterators"; local function generate_ring(nodes, num_replicas, hash) local new_ring = {}; for _, node_name in ipairs(nodes) do for replica = 1, num_replicas do local replica_hash = hash(node_name..":"..replica); new_ring[replica_hash] = node_name; table.insert(new_ring, replica_hash); end end table.sort(new_ring); return new_ring; end local hashring_methods = {}; local hashring_mt = { __index = function (self, k) -- Automatically build self.ring if it's missing if k == "ring" then local ring = generate_ring(self.nodes, self.num_replicas, self.hash); rawset(self, "ring", ring); return ring; end return rawget(hashring_methods, k); end }; local function new(num_replicas, hash_function) return setmetatable({ nodes = {}, num_replicas = num_replicas, hash = hash_function }, hashring_mt); end; function hashring_methods:add_node(name, value) self.ring = nil; self.nodes[name] = value == nil and true or value; table.insert(self.nodes, name); return true; end function hashring_methods:add_nodes(nodes) self.ring = nil; local iter = pairs; if nodes[1] then -- simple array? iter = it.values; end for node_name, node_value in iter(nodes) do if self.nodes[node_name] == nil then self.nodes[node_name] = node_value == nil and true or node_value; table.insert(self.nodes, node_name); end end return true; end function hashring_methods:remove_node(node_name) self.ring = nil; if self.nodes[node_name] ~= nil then for i, stored_node_name in ipairs(self.nodes) do if node_name == stored_node_name then self.nodes[node_name] = nil; table.remove(self.nodes, i); return true; end end end return false; end function hashring_methods:remove_nodes(nodes) self.ring = nil; for _, node_name in ipairs(nodes) do self:remove_node(node_name); end end function hashring_methods:clone() local clone_hashring = new(self.num_replicas, self.hash); for node_name, node_value in pairs(self.nodes) do clone_hashring.nodes[node_name] = node_value; end clone_hashring.ring = nil; return clone_hashring; end function hashring_methods:get_node(key) local node; local key_hash = self.hash(key); for _, replica_hash in ipairs(self.ring) do if key_hash < replica_hash then node = self.ring[replica_hash]; break; end end if not node then node = self.ring[self.ring[1]]; end return node, self.nodes[node]; end return { new = new; }