| -- |
| -- 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 resty_chash = require("resty.chash") |
| local str_char = string.char |
| local str_gsub = string.gsub |
| local pairs = pairs |
| |
| |
| local CONSISTENT_POINTS = 160 -- points per server, taken from `resty.chash` |
| |
| |
| local _M = {} |
| |
| |
| local function fetch_chash_hash_key(ctx, upstream) |
| local key = upstream.key |
| local hash_on = upstream.hash_on or "vars" |
| local chash_key |
| |
| if hash_on == "consumer" then |
| chash_key = ctx.consumer_name |
| elseif hash_on == "vars" then |
| chash_key = ctx.var[key] |
| elseif hash_on == "header" then |
| chash_key = ctx.var["http_" .. key] |
| elseif hash_on == "cookie" then |
| chash_key = ctx.var["cookie_" .. key] |
| elseif hash_on == "vars_combinations" then |
| local err |
| chash_key, err = core.utils.resolve_var(key, ctx.var); |
| if err then |
| core.log.error("could not resolve vars in ", key, " error: ", err) |
| end |
| end |
| |
| if not chash_key then |
| chash_key = ctx.var["remote_addr"] |
| core.log.warn("chash_key fetch is nil, use default chash_key ", |
| "remote_addr: ", chash_key) |
| end |
| core.log.info("upstream key: ", key) |
| core.log.info("hash_on: ", hash_on) |
| core.log.info("chash_key: ", core.json.delay_encode(chash_key)) |
| |
| return chash_key |
| end |
| |
| |
| function _M.new(up_nodes, upstream) |
| local str_null = str_char(0) |
| |
| local nodes_count = 0 |
| local safe_limit = 0 |
| local servers, nodes = {}, {} |
| for serv, weight in pairs(up_nodes) do |
| local id = str_gsub(serv, ":", str_null) |
| |
| nodes_count = nodes_count + 1 |
| safe_limit = safe_limit + weight |
| servers[id] = serv |
| nodes[id] = weight |
| end |
| safe_limit = safe_limit * CONSISTENT_POINTS |
| |
| local picker = resty_chash:new(nodes) |
| return { |
| upstream = upstream, |
| get = function (ctx) |
| local id |
| if ctx.balancer_tried_servers then |
| if ctx.balancer_tried_servers_count == nodes_count then |
| return nil, "all upstream servers tried" |
| end |
| |
| -- the 'safe_limit' is a best effort limit to prevent infinite loop caused by bug |
| for i = 1, safe_limit do |
| id, ctx.chash_last_server_index = picker:next(ctx.chash_last_server_index) |
| if not ctx.balancer_tried_servers[servers[id]] then |
| break |
| end |
| end |
| else |
| local chash_key = fetch_chash_hash_key(ctx, upstream) |
| id, ctx.chash_last_server_index = picker:find(chash_key) |
| end |
| -- core.log.warn("chash id: ", id, " val: ", servers[id]) |
| return servers[id] |
| end, |
| after_balance = function (ctx, before_retry) |
| 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[ctx.balancer_server] = true |
| ctx.balancer_tried_servers_count = (ctx.balancer_tried_servers_count or 0) + 1 |
| 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 |
| |
| ctx.balancer_tried_servers_count = 0 |
| end, |
| } |
| end |
| |
| |
| return _M |