| -- |
| -- Licensed to the Apache Software Foundation (ASF) under one or more |
| -- contributor license agreements. See the NOTICE file distributed with |
| -- this work for additional information regarding copyright ownership. |
| -- The ASF licenses this file to You under the Apache License, Version 2.0 |
| -- (the "License"); you may not use this file except in compliance with |
| -- the License. You may obtain a copy of the License at |
| -- |
| -- http://www.apache.org/licenses/LICENSE-2.0 |
| -- |
| -- Unless required by applicable law or agreed to in writing, software |
| -- distributed under the License is distributed on an "AS IS" BASIS, |
| -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| -- See the License for the specific language governing permissions and |
| -- limitations under the License. |
| -- |
| |
| local core = require("apisix.core") |
| local binaryHeap = require("binaryheap") |
| local ipairs = ipairs |
| local pairs = pairs |
| |
| |
| local _M = {} |
| |
| |
| local function least_score(a, b) |
| return a.score < b.score |
| end |
| |
| |
| function _M.new(up_nodes, upstream) |
| local servers_heap = binaryHeap.minUnique(least_score) |
| for server, weight in pairs(up_nodes) do |
| local score = 1 / weight |
| -- Note: the argument order of insert is different from others |
| servers_heap:insert({ |
| server = server, |
| effect_weight = 1 / weight, |
| score = score, |
| }, server) |
| end |
| |
| return { |
| upstream = upstream, |
| get = function (ctx) |
| local server, info, err |
| if ctx.balancer_tried_servers then |
| local tried_server_list = {} |
| while true do |
| server, info = servers_heap:peek() |
| -- we need to let the retry > #nodes so this branch can be hit and |
| -- the request will retry next priority of nodes |
| if server == nil then |
| err = "all upstream servers tried" |
| break |
| end |
| |
| if not ctx.balancer_tried_servers[server] then |
| break |
| end |
| |
| servers_heap:pop() |
| core.table.insert(tried_server_list, info) |
| end |
| |
| for _, info in ipairs(tried_server_list) do |
| servers_heap:insert(info, info.server) |
| end |
| else |
| server, info = servers_heap:peek() |
| end |
| |
| if not server then |
| return nil, err |
| end |
| |
| info.score = info.score + info.effect_weight |
| servers_heap:update(server, info) |
| return server |
| end, |
| after_balance = function (ctx, before_retry) |
| local server = ctx.balancer_server |
| local info = servers_heap:valueByPayload(server) |
| info.score = info.score - info.effect_weight |
| servers_heap:update(server, info) |
| |
| if not before_retry then |
| if ctx.balancer_tried_servers then |
| core.tablepool.release("balancer_tried_servers", ctx.balancer_tried_servers) |
| ctx.balancer_tried_servers = nil |
| end |
| |
| return nil |
| end |
| |
| if not ctx.balancer_tried_servers then |
| ctx.balancer_tried_servers = core.tablepool.fetch("balancer_tried_servers", 0, 2) |
| end |
| |
| ctx.balancer_tried_servers[server] = true |
| end, |
| before_retry_next_priority = function (ctx) |
| if ctx.balancer_tried_servers then |
| core.tablepool.release("balancer_tried_servers", ctx.balancer_tried_servers) |
| ctx.balancer_tried_servers = nil |
| end |
| end, |
| } |
| end |
| |
| |
| return _M |