mirrors/prosody
1
0
Fork 0
mirror of https://github.com/bjc/prosody.git synced 2025-04-01 20:27:39 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions

util.hashring: Support associating arbitrary data with nodes

Browse source 
In this API, a 'node' is always a simple text string. Sometimes the caller may
have a more complex structure representing a node, but the hash ring is really
only concerned with the node's name.

This API change allows :add_nodes() to take a table of `node_name = value`
pairs, as well as the simple array of node names previously accepted.

The 'value' of the selected node is returned as a new second result from
:get_node().

If no value is passed when a node is added, it defaults to `true` (as before,
but this was never previously exposed).
This commit is contained in:
Matthew Wild 2022-12-02 20:32:36 +00:00
parent d33904f7e9
commit ae84717255
2 changed files with 30 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

7
spec/util_hashring_spec.lua
View file

@ -83,4 +83,11 @@ describe("util.hashring", function ()
end
end);
it("should support values associated with nodes", function ()
local r = hashring.new(128, sha256);
r:add_node("node1", { a = 1 });
local node, value = r:get_node("foo");
assert.is_equal("node1", node);
assert.same({ a = 1 }, value);
end);
end);

32
util/hashring.lua
View file

@ -1,3 +1,5 @@
local it = require "util.iterators";
local function generate_ring(nodes, num_replicas, hash)
local new_ring = {};
for _, node_name in ipairs(nodes) do
@ -28,18 +30,22 @@ 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)
function hashring_methods:add_node(name, value)
self.ring = nil;
self.nodes[name] = true;
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;
for _, node_name in ipairs(nodes) do
if not self.nodes[node_name] then
self.nodes[node_name] = true;
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
@ -48,7 +54,7 @@ end
function hashring_methods:remove_node(node_name)
self.ring = nil;
if self.nodes[node_name] then
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;
@ -69,18 +75,26 @@ end
function hashring_methods:clone()
local clone_hashring = new(self.num_replicas, self.hash);
clone_hashring:add_nodes(self.nodes);
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
return self.ring[replica_hash];
node = self.ring[replica_hash];
break;
end
end
return self.ring[self.ring[1]];
if not node then
node = self.ring[self.ring[1]];
end
return node, self.nodes[node];
end
return {