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util/hashring.lua @ 12179:5e68635cdc2c
mod_http_file_share: Always measure total disk usage for statistics!
Metrics available or not depending on configuration is weird, even tho
it might be expensive to calculate and it's only really needed when
there is a global quota.
Default quota is set to infinity, which is essentially what it was.
Reports NaN if there is an error, which should count as over the
infinite default quota.
author | Kim Alvefur <zash@zash.se> |
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date | Tue, 11 Jan 2022 04:15:29 +0100 |
parent | 11208:96429946a742 |
child | 12795:87424cbedc55 |
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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) self.ring = nil; self.nodes[name] = true; table.insert(self.nodes, name); return true; end function hashring_methods:add_nodes(nodes) self.ring = nil; for _, node_name in ipairs(nodes) do if not self.nodes[node_name] then self.nodes[node_name] = true; 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] 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); clone_hashring:add_nodes(self.nodes); return clone_hashring; end function hashring_methods:get_node(key) local key_hash = self.hash(key); for _, replica_hash in ipairs(self.ring) do if key_hash < replica_hash then return self.ring[replica_hash]; end end return self.ring[self.ring[1]]; end return { new = new; }