refactor lua balancer and fix ipv6 issue

rootfs/etc/nginx/lua/balancer/chash.lua

@@ -1,7 +1,6 @@
 local balancer_resty = require("balancer.resty")
 local resty_chash = require("resty.chash")
 local util = require("util")
-local split = require("util.split")
 
 local _M = balancer_resty:new({ factory = resty_chash, name = "chash" })
 
@@ -15,8 +14,7 @@ end
 
 function _M.balance(self)
   local key = util.lua_ngx_var(self.hash_by)
-  local endpoint_string = self.instance:find(key)
-  return split.split_pair(endpoint_string, ":")
+  return self.instance:find(key)
 end
 
 return _M

rootfs/etc/nginx/lua/balancer/ewma.lua

@@ -128,7 +128,8 @@ function _M.balance(self)
     endpoint = pick_and_score(peer_copy, k)
   end
 
-  return endpoint.address, endpoint.port
+  -- TODO(elvinefendi) move this processing to _M.sync
+  return endpoint.address .. ":" .. endpoint.port
 end
 
 function _M.after_balance(_)

rootfs/etc/nginx/lua/balancer/round_robin.lua

@@ -1,7 +1,6 @@
 local balancer_resty = require("balancer.resty")
 local resty_roundrobin = require("resty.roundrobin")
 local util = require("util")
-local split = require("util.split")
 
 local _M = balancer_resty:new({ factory = resty_roundrobin, name = "round_robin" })
 
@@ -14,8 +13,7 @@ function _M.new(self, backend)
 end
 
 function _M.balance(self)
-  local endpoint_string = self.instance:find()
-  return split.split_pair(endpoint_string, ":")
+  return self.instance:find()
 end
 
 return _M

rootfs/etc/nginx/lua/balancer/sticky.lua

@@ -1,7 +1,6 @@
 local balancer_resty = require("balancer.resty")
 local resty_chash = require("resty.chash")
 local util = require("util")
-local split = require("util.split")
 local ck = require("resty.cookie")
 
 local _M = balancer_resty:new({ factory = resty_chash, name = "sticky" })
@@ -56,7 +55,7 @@ local function pick_random(instance)
   return instance:next(index)
 end
 
-local function sticky_endpoint_string(self)
+function _M.balance(self)
   local cookie, err = ck:new()
   if not cookie then
     ngx.log(ngx.ERR, err)
@@ -73,9 +72,4 @@ local function sticky_endpoint_string(self)
   return self.instance:find(key)
 end
 
-function _M.balance(self)
-  local endpoint_string = sticky_endpoint_string(self)
-  return split.split_pair(endpoint_string, ":")
-end
-
 return _M