refactor balancer into more testable and extensible interface
This commit is contained in:
Elvin Efendi
parent
1b5db4b3b0
commit
e9dc275b81
20 changed files with 368 additions and 467 deletions
21
rootfs/etc/nginx/lua/balancer/chash.lua
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21
rootfs/etc/nginx/lua/balancer/chash.lua
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@ -0,0 +1,21 @@
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local balancer_resty = require("balancer.resty")
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local resty_chash = require("resty.chash")
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local util = require("util")
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local _M = balancer_resty:new({ factory = resty_chash, name = "chash" })
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function _M.new(self, backend)
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local nodes = util.get_nodes(backend.endpoints)
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local o = { instance = self.factory:new(nodes), hash_by = backend["upstream-hash-by"] }
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setmetatable(o, self)
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self.__index = self
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return o
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end
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function _M.balance(self)
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local key = util.lua_ngx_var(self.hash_by)
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local endpoint_string = self.instance:find(key)
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return util.split_pair(endpoint_string, ":")
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end
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return _M
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@ -14,7 +14,7 @@ local PICK_SET_SIZE = 2
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local ewma_lock = resty_lock:new("locks", {timeout = 0, exptime = 0.1})
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local _M = {}
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local _M = { name = "ewma" }
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local function lock(upstream)
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local _, err = ewma_lock:lock(upstream .. LOCK_KEY)
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@ -117,17 +117,18 @@ local function pick_and_score(peers, k)
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return peers[lowest_score_index]
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end
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function _M.balance(backend)
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local peers = backend.endpoints
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function _M.balance(self)
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local peers = self.peers
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if #peers == 1 then
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return peers[1]
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end
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local k = (#peers < PICK_SET_SIZE) and #peers or PICK_SET_SIZE
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local peer_copy = util.deepcopy(peers)
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return pick_and_score(peer_copy, k)
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local endpoint = pick_and_score(peer_copy, k)
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return endpoint.address, endpoint.port
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end
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function _M.after_balance()
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function _M.after_balance(_)
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local response_time = tonumber(util.get_first_value(ngx.var.upstream_response_time)) or 0
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local connect_time = tonumber(util.get_first_value(ngx.var.upstream_connect_time)) or 0
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local rtt = connect_time + response_time
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@ -139,10 +140,21 @@ function _M.after_balance()
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get_or_update_ewma(upstream, rtt, true)
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end
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function _M.sync(_)
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function _M.sync(self, backend)
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local changed = not util.deep_compare(self.peers, backend.endpoints)
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if not changed then
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return
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end
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-- TODO: Reset state of EWMA per backend
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ngx.shared.balancer_ewma:flush_all()
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ngx.shared.balancer_ewma_last_touched_at:flush_all()
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end
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function _M.new(self, backend)
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local o = { peers = backend.endpoints }
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setmetatable(o, self)
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self.__index = self
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return o
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end
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return _M
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@ -1,142 +1,25 @@
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local resty_roundrobin = require("resty.roundrobin")
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local resty_chash = require("resty.chash")
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local util = require("util")
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local ck = require("resty.cookie")
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local _M = {}
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local instances = {}
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local function get_resty_balancer_nodes(endpoints)
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local nodes = {}
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local weight = 1
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for _, endpoint in pairs(endpoints) do
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local endpoint_string = endpoint.address .. ":" .. endpoint.port
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nodes[endpoint_string] = weight
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end
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return nodes
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function _M.new(self, o)
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o = o or {}
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setmetatable(o, self)
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self.__index = self
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return o
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end
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local function init_resty_balancer(factory, instance, endpoints)
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local nodes = get_resty_balancer_nodes(endpoints)
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if instance then
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instance:reinit(nodes)
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else
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instance = factory:new(nodes)
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function _M.sync(self, backend)
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local nodes = util.get_nodes(backend.endpoints)
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local changed = not util.deep_compare(self.instance.nodes, nodes)
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if not changed then
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return
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end
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return instance
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self.instance:reinit(nodes)
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end
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local function is_sticky(backend)
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return backend["sessionAffinityConfig"] and backend["sessionAffinityConfig"]["name"] == "cookie"
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end
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local function cookie_name(backend)
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return backend["sessionAffinityConfig"]["cookieSessionAffinity"]["name"] or "route"
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end
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local function encrypted_endpoint_string(backend, endpoint_string)
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local encrypted, err
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if backend["sessionAffinityConfig"]["cookieSessionAffinity"]["hash"] == "sha1" then
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encrypted, err = util.sha1_digest(endpoint_string)
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else
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encrypted, err = util.md5_digest(endpoint_string)
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end
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if err ~= nil then
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ngx.log(ngx.ERR, err)
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end
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return encrypted
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end
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local function set_cookie(backend, value)
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local cookie, err = ck:new()
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if not cookie then
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ngx.log(ngx.ERR, err)
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end
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local ok
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ok, err = cookie:set({
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key = cookie_name(backend),
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value = value,
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path = "/",
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domain = ngx.var.host,
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httponly = true,
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})
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if not ok then
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ngx.log(ngx.ERR, err)
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end
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end
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local function pick_random(instance)
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local index = math.random(instance.npoints)
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return instance:next(index)
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end
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local function sticky_endpoint_string(instance, backend)
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local cookie, err = ck:new()
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if not cookie then
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ngx.log(ngx.ERR, err)
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return pick_random(instance)
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end
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local key = cookie:get(cookie_name(backend))
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if not key then
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local tmp_endpoint_string = pick_random(instance)
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key = encrypted_endpoint_string(backend, tmp_endpoint_string)
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set_cookie(backend, key)
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end
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return instance:find(key)
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end
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function _M.is_applicable(backend)
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return is_sticky(backend) or backend["upstream-hash-by"] or backend["load-balance"] == "round_robin"
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end
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function _M.balance(backend)
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local instance = instances[backend.name]
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if not instance then
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ngx.log(ngx.ERR, "no LB algorithm instance was found")
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return nil
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end
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local endpoint_string
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if is_sticky(backend) then
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endpoint_string = sticky_endpoint_string(instance, backend)
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elseif backend["upstream-hash-by"] then
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local key = util.lua_ngx_var(backend["upstream-hash-by"])
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endpoint_string = instance:find(key)
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else
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endpoint_string = instance:find()
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end
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local address, port = util.split_pair(endpoint_string, ":")
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return { address = address, port = port }
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end
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function _M.sync(backend)
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local instance = instances[backend.name]
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local factory = resty_roundrobin
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if is_sticky(backend) or backend["upstream-hash-by"] then
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factory = resty_chash
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end
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if instance then
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local mt = getmetatable(instance)
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if mt.__index ~= factory then
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ngx.log(ngx.INFO, "LB algorithm has been changed, resetting the instance")
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instance = nil
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end
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end
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instances[backend.name] = init_resty_balancer(factory, instance, backend.endpoints)
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end
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function _M.after_balance()
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function _M.after_balance(_)
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end
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return _M
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20
rootfs/etc/nginx/lua/balancer/round_robin.lua
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20
rootfs/etc/nginx/lua/balancer/round_robin.lua
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@ -0,0 +1,20 @@
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local balancer_resty = require("balancer.resty")
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local resty_roundrobin = require("resty.roundrobin")
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local util = require("util")
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local _M = balancer_resty:new({ factory = resty_roundrobin, name = "round_robin" })
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function _M.new(self, backend)
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local nodes = util.get_nodes(backend.endpoints)
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local o = { instance = self.factory:new(nodes) }
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setmetatable(o, self)
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self.__index = self
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return o
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end
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function _M.balance(self)
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local endpoint_string = self.instance:find()
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return util.split_pair(endpoint_string, ":")
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end
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return _M
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80
rootfs/etc/nginx/lua/balancer/sticky.lua
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80
rootfs/etc/nginx/lua/balancer/sticky.lua
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@ -0,0 +1,80 @@
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local balancer_resty = require("balancer.resty")
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local resty_chash = require("resty.chash")
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local util = require("util")
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local ck = require("resty.cookie")
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local _M = balancer_resty:new({ factory = resty_chash, name = "sticky" })
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function _M.new(self, backend)
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local nodes = util.get_nodes(backend.endpoints)
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local digest_func = util.md5_digest
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if backend["sessionAffinityConfig"]["cookieSessionAffinity"]["hash"] == "sha1" then
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digest_func = util.sha1_digest
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end
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local o = {
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instance = self.factory:new(nodes),
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cookie_name = backend["sessionAffinityConfig"]["cookieSessionAffinity"]["name"] or "route",
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digest_func = digest_func,
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}
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setmetatable(o, self)
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self.__index = self
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return o
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end
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local function encrypted_endpoint_string(self, endpoint_string)
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local encrypted, err = self.digest_func(endpoint_string)
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if err ~= nil then
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ngx.log(ngx.ERR, err)
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end
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return encrypted
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end
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local function set_cookie(self, value)
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local cookie, err = ck:new()
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if not cookie then
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ngx.log(ngx.ERR, err)
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end
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local ok
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ok, err = cookie:set({
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key = self.cookie_name,
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value = value,
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path = "/",
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domain = ngx.var.host,
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httponly = true,
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})
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if not ok then
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ngx.log(ngx.ERR, err)
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end
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end
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local function pick_random(instance)
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local index = math.random(instance.npoints)
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return instance:next(index)
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end
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local function sticky_endpoint_string(self)
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local cookie, err = ck:new()
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if not cookie then
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ngx.log(ngx.ERR, err)
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return pick_random(self.instance)
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end
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local key = cookie:get(self.cookie_name)
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if not key then
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local tmp_endpoint_string = pick_random(self.instance)
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key = encrypted_endpoint_string(self, tmp_endpoint_string)
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set_cookie(self, key)
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end
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return self.instance:find(key)
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end
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function _M.balance(self)
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local endpoint_string = sticky_endpoint_string(self)
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return util.split_pair(endpoint_string, ":")
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end
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return _M
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