optimize ngx resolver

nginx/conf/nginx.conf

@@ -38,6 +38,7 @@ http {
     init_by_lua_file "lua/luainit/init.lua";
     init_worker_by_lua_file "lua/luabiz/settle.lua";
 
+
     #gzip  on;
     server {
         listen       8080;
@@ -68,8 +69,8 @@ http {
 
 
         location / {
-            root   html;
-            index  index.html index.htm;
+            root   /Users/zhoush/Documents/Private/Notes/;
+            index README.html;
             lua_code_cache on;
             log_by_lua_block {
                 local logger = require("socket")
@@ -96,16 +97,11 @@ http {
             }
         }
 
-        location /regex {
+        location /get_addr {
             content_by_lua_block {
-                local str = '2018-08-15'
-                local regex = [[(\d+)-(\d+)-(\d+)]]
-                local r = ngx.re.match(str, regex, 'jo')
-                if r then
-                ngx.say(r[1], r[2], r[3])
-                else
-                ngx.say('no matched')
-                end
+                local zx_base = loadmod("zx_base")
+                local host = zx_base:_get_addr("www.baidu.com")
+                ngx.say(host)
                 }
         }
 

nginx/lua/luabiz/async.lua

@@ -5,68 +5,72 @@ local mysql = loadmod("resty.mysql")
 local json = loadmod('cjson')
 local zx_base = loadmod('zx_base')
 
-local function async_sql_ins()
-  local pay_type
-  local rate = 305
-  local reqs = json.decode(ngx.var.request_body)
-
-  if reqs["code"] ~= "SUCCESS" then
-    return nil
-  end
-
-  if string.find(reqs["trade_type"], "alipay") then
-    pay_type = "12"
-  elseif string.find(reqs["trade_type"], "weixin") then
-    pay_type = "11"
-  end
-
-  local ins_sql = string.format(
-    [[INSERT INTO pay_noty_trace SET host_map_id = 3, tkpay_order_no = %d, channel_order_no = %s, host_order_no = %s,
-      pay_type = %s, trans_amt = %s, trans_time = %s, trans_status = %s, currency = '%s', rate = %d]],
-      reqs['out_transaction_no'], reqs['out_trade_no'],
-      reqs['transaction_no'], pay_type, reqs['total_amount'] * 100,
-      reqs['time_start'], "0", reqs['currency'], rate)
-  zx_base:log("ASYNC_SQL", ins_sql)
-  return ins_sql
-end
-
-local function async_db(ins_sql)
-  local db, err = mysql:new()
-
-  if not db then
-    zx_base:log("ASYNC_DB", "failed to instantiate mysql: ", err)
-    return false
-  end
-
-  db:set_timeout(1000) -- 1 sec
-
-  local db_st = zx_base:db_read()
-  local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
-    port     = db_st['port'],
-    database = db_st['database'],
-    user     = db_st['user'],
-    password = db_st['password'],
-    timeout  = db_st['timeout'],
-    charset  = 'utf8'
-  }
-
-  if not ok then
-    zx_base:log("ASYNC_DB",  err, ": ", errcode, " ", sqlstate)
-    return
-  end
-
-  local res, err, errcode, sqlstate = db:query(ins_sql)
-  if not res then
-    zx_base:log("ASYNC_DB", "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
-    return
-  end
-
-  db:set_keepalive(10000, 100)
-end
+-- local function async_sql_ins()
+--   local pay_type
+--   local rate = 305
+--   local reqs = json.decode(ngx.var.request_body)
+
+--   if reqs["code"] ~= "SUCCESS" then
+--     return nil
+--   end
+
+--   if string.find(reqs["trade_type"], "alipay") then
+--     pay_type = "12"
+--   elseif string.find(reqs["trade_type"], "weixin") then
+--     pay_type = "11"
+--   end
+
+--   local ins_sql = string.format(
+--     [[INSERT INTO pay_noty_trace SET host_map_id = 3, tkpay_order_no = %d, channel_order_no = %s, host_order_no = %s,
+--       pay_type = %s, trans_amt = %s, trans_time = %s, trans_status = %s, currency = '%s', rate = %d]],
+--       reqs['out_transaction_no'], reqs['out_trade_no'],
+--       reqs['transaction_no'], pay_type, reqs['total_amount'] * 100,
+--       reqs['time_start'], "0", reqs['currency'], rate)
+--   zx_base:log("ASYNC_SQL", ins_sql)
+--   return ins_sql
+-- end
+
+-- local function async_db(ins_sql)
+--   local db, err = mysql:new()
+
+--   if not db then
+--     zx_base:log("ASYNC_DB", "failed to instantiate mysql: ", err)
+--     return false
+--   end
+
+--   db:set_timeout(1000) -- 1 sec
+
+--   local db_st = zx_base:db_read()
+--   local ok, err, errcode, sqlstate = db:connect{
+--     host     = zx_base:_get_addr(db_st['host']),
+--     port     = db_st['port'],
+--     database = db_st['database'],
+--     user     = db_st['user'],
+--     password = db_st['password'],
+--     timeout  = db_st['timeout'],
+--     charset  = 'utf8'
+--   }
+
+--   if not ok then
+--     zx_base:log("ASYNC_DB",  err, ": ", errcode, " ", sqlstate)
+--     return
+--   end
+
+--   local res, err, errcode, sqlstate = db:query(ins_sql)
+--   if not res then
+--     zx_base:log("ASYNC_DB", "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
+--     return
+--   end
+
+--   db:set_keepalive(10000, 100)
+-- end
 
 local function eof()
-  if ngx.var.host == "icm-test.suixingpay.com" then
+  ngx.log(ngx.NOTICE, ngx.req.raw_header())
+  ngx.log(ngx.NOTICE, ngx.var.http_refer)
+
+  -- if ngx.var.hostname == "icm-test.suixingpay.com" then
+  if ngx.var.remote_addr == "106.37.197.50" then
     ngx.say("{\"code\":\"success\", \"msg\":\"成功\"}")
   else
     ngx.say("SUCCESS")

nginx/lua/luabiz/node_asb.lua

@@ -21,7 +21,7 @@ local function asb_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_asbdetail.lua

@@ -22,7 +22,7 @@ local function asbdetail_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_card.lua

@@ -23,7 +23,7 @@ local function card_sql(db_st, total_time)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],
@@ -56,26 +56,27 @@ local function card_sql(db_st, total_time)
     return
   end
 
-  -- INSERT INTO history table
-  local sql_insert = string.format([[INSERT INTO node_card_his SELECT * FROM node_card ]]..
-    [[WHERE DATE(`create_time`) < DATE('%s')]],
-    os.date("%Y%m%d%H%M%S", total_time - 24 * 60 * 60))
-  ngx.log(ngx.NOTICE, sql_insert)
-  local res, err, errcode, sqlstate = db:query(sql_insert)
-  if not res then
-    ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
-    return
-  end
-
-  -- DELETE current tables record
-  local sql_delete = string.format([[DELETE FROM node_card WHERE DATE(`create_time`) < DATE('%s')]],
-    os.date("%Y%m%d%H%M%S", total_time - 24 * 60 * 60 ))
-  ngx.log(ngx.NOTICE, sql_delete)
-  local res, err, errcode, sqlstate = db:query(sql_delete)
-  if not res then
-    ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
-    return
-  end
+  -- -- INSERT INTO history table
+  -- local sql_insert = string.format([[INSERT INTO node_card_his SELECT * FROM node_card ]]..
+  --   -- [[WHERE DATE(`create_time`) < DATE('%s')]],
+  --     -- [[WHERE EXTRACT(YEAR_MONTH FROM `create_time`) = EXTRACT(YEAR_MONTH FROM DATE_SUB('%s', INTERVAL 3 MONTH))]],
+  --   os.date("%Y%m%d%H%M%S", total_time))
+  -- ngx.log(ngx.NOTICE, sql_insert)
+  -- local res, err, errcode, sqlstate = db:query(sql_insert)
+  -- if not res then
+  --   ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
+  --   return
+  -- end
+
+  -- -- DELETE current tables record
+  -- local sql_delete = string.format([[DELETE FROM node_card WHERE DATE(`create_time`) < DATE('%s')]],
+  --   os.date("%Y%m%d%H%M%S", total_time - 24 * 60 * 60 ))
+  -- ngx.log(ngx.NOTICE, sql_delete)
+  -- local res, err, errcode, sqlstate = db:query(sql_delete)
+  -- if not res then
+  --   ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
+  --   return
+  -- end
 
   ngx.log(ngx.NOTICE, "-----------------------> END")
   zx_base:close_db(db)

nginx/lua/luabiz/node_chgrule.lua

@@ -24,7 +24,7 @@ local function chgrule_sql(db_st)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_cs.lua

@@ -23,7 +23,7 @@ local function cs_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_csdetail.lua

@@ -24,7 +24,7 @@ local function csdetail_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_ms.lua

@@ -22,7 +22,7 @@ local function ms_sql(db_st)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_payment.lua

@@ -24,7 +24,7 @@ local function payment_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_psb.lua

@@ -23,7 +23,7 @@ local function psb_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_psbdetail.lua

@@ -23,7 +23,7 @@ local function psbdetail_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_rchg.lua

@@ -23,7 +23,7 @@ local function rchg_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_rchgdetail.lua

@@ -23,7 +23,7 @@ local function rchgdetail_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_saledetail.lua

@@ -24,7 +24,7 @@ local function saledetail_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_saleorder.lua

@@ -22,7 +22,7 @@ local function saleorder_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_shift.lua

@@ -24,7 +24,7 @@ local function shift_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_sku.lua

@@ -24,7 +24,7 @@ local function sku_sql(db_st)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_sms.lua

@@ -24,7 +24,7 @@ local function sms_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_smsvip.lua

@@ -24,7 +24,7 @@ local function smsvip_sql(db_st, interval)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/node_ticket.lua

@@ -20,7 +20,7 @@ local function ticket_sql(db_st, total_time)
   db:set_timeout(1000) -- 1 sec
 
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],
@@ -44,28 +44,27 @@ local function ticket_sql(db_st, total_time)
     return
   end
 
-  -- INSERT INTO history table
-  local sql_insert = string.format([[INSERT INTO node_ticket_his SELECT * FROM node_ticket WHERE ]]..
-      [[DATE(`create_time`) < DATE('%s')]],
-    os.date("%Y%m%d%H%M%S", total_time - 24 * 60 * 60))
-  ngx.log(ngx.NOTICE, sql_insert)
-  local res, err, errcode, sqlstate = db:query(sql_insert)
-  if not res then
-    ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
-    return
-  end
-
-
-  -- DELETE current tables record
-  local sql_delete = string.format([[DELETE FROM node_ticket WHERE DATE(`create_time`) < DATE('%s')]],
-    os.date("%Y%m%d%H%M%S", total_time - 24 * 60 * 60))
-  ngx.log(ngx.NOTICE, sql_delete)
-  local res, err, errcode, sqlstate = db:query(sql_delete)
-  if not res then
-    ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
-    return
-  end
-  ngx.log(ngx.NOTICE,  "-----------------------> END")
+  -- -- INSERT INTO history table
+  -- local sql_insert = string.format([[INSERT INTO node_ticket_his SELECT * FROM node_ticket WHERE ]]..
+  --     [[DATE(`create_time`) < DATE('%s')]],
+  --   os.date("%Y%m%d%H%M%S", total_time - 24 * 60 * 60))
+  -- ngx.log(ngx.NOTICE, sql_insert)
+  -- local res, err, errcode, sqlstate = db:query(sql_insert)
+  -- if not res then
+  --   ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
+  --   return
+  -- end
+
+  -- -- DELETE current tables record
+  -- local sql_delete = string.format([[DELETE FROM node_ticket WHERE DATE(`create_time`) < DATE('%s')]],
+  --   os.date("%Y%m%d%H%M%S", total_time - 24 * 60 * 60))
+  -- ngx.log(ngx.NOTICE, sql_delete)
+  -- local res, err, errcode, sqlstate = db:query(sql_delete)
+  -- if not res then
+  --   ngx.log(ngx.ERR, "bad result: ", err, ": ", errcode, ": ", sqlstate, ".")
+  --   return
+  -- end
+  -- ngx.log(ngx.NOTICE,  "-----------------------> END")
 
   zx_base:close_db(db)
 end

nginx/lua/luabiz/node_vipacct.lua

@@ -37,7 +37,7 @@ local function vipacct_sql(db_st)
 
   -- 连接分节点
   local ok, err, errcode, sqlstate = db:connect{
-    host     = db_st['host'],
+    host     = zx_base:_get_addr(db_st['host']),
     port     = db_st['port'],
     database = db_st['database'],
     user     = db_st['user'],

nginx/lua/luabiz/settle.lua

@@ -34,14 +34,9 @@ local nxt_time = zx_base:date2time(os.date("%Y-%m-%d 00:30:00", os.time()+24*60*
 local now_time = os.time();
 local delay = nxt_time - now_time;
 
--- local settledate = os.date('%Y-%m-%d', os.time())
--- local now_time = zx_base:date2time(settledate)
-local handler
 
-handler = function(premature, now_time)
+local function handler(premature)
   if not premature then
-    -- if nowtime == now_time then
-
     -- settle features start
 
     --       node_asb:        run()
@@ -74,18 +69,7 @@ handler = function(premature, now_time)
       handle:close()
     end
 
-      -- -- reset now_time
-      -- now_time = tostring(tonumber(now_time) - 1)
-
-      -- reset settle time
-      -- settledate = os.date('%Y-%m-%d', os.time())
-      -- now_time = zx_base:date2time(settledate)
-
-    -- end
-    nxt_time = zx_base:date2time(os.date("%Y-%m-%d 00:30:00", os.time()+24*60*60))
-    now_time = os.time();
-    delay = nxt_time - now_time;
-    local ok, err = ngx.timer.every(24 * 60 * 60, handler, now_time)
+    local ok, err = ngx.timer.every(24*60*60, handler, os.time())
     if not ok then
       ngx.log(ngx.ERR, "failed to create the timer:", err)
       return
@@ -94,7 +78,7 @@ handler = function(premature, now_time)
 end
 
 if ngx.worker.id() == 0 then
-  local ok, err = ngx.timer.at(delay, handler, now_time)
+  local ok, err = ngx.timer.at(delay, handler)
   if not ok then
     ngx.log(ngx.ERR, "failed to create the timer:", err)
     return

nginx/lua/luabiz/tk_sdt.lua

@@ -31,7 +31,7 @@ local function sdt_sql(tk_biz, tk_control, total_time)
 
    -- 连接tk_biz
    local ok, err, errcode, sqlstate = db_biz:connect{
-      host     = tk_biz['host'],
+      host     = zx_base:_get_addr(tk_biz['host']),
       port     = tk_biz['port'],
       database = tk_biz['database'],
       user     = tk_biz['user'],
@@ -56,7 +56,7 @@ local function sdt_sql(tk_biz, tk_control, total_time)
 
    -- 连接tk_control
    local ok, err, errcode, sqlstate = db_control:connect{
-      host     = tk_control['host'],
+      host     = zx_base:_get_addr(tk_control['host']),
       port     = tk_control['port'],
       database = tk_control['database'],
       user     = tk_control['user'],

nginx/lua/luabiz/tk_sync.lua

@@ -34,7 +34,7 @@ local function sync_sql(tk_biz, tk_control, tk_table)
   db:set_timeout(1000)          -- 1 sec
   -- 连接节点机MySQL
   local ok, err, errcode, sqlstate = db:connect{
-    host     = tk_biz['host'],
+    host     = zx_base:_get_addr(tk_biz['host']),
     port     = tk_biz['port'],
     database = tk_biz['database'],
     user     = tk_biz['user'],
@@ -76,7 +76,7 @@ local function sync_sql(tk_biz, tk_control, tk_table)
   db:set_timeout(1000)
   -- 连接总控机MySQL
   ok, err, errcode, sqlstate = db:connect{
-    host     = tk_control['host'],
+    host     = zx_base:_get_addr(tk_control['host']),
     port     = tk_control['port'],
     database = tk_control['database'],
     user     = tk_control['user'],

nginx/lua/luabiz/zx_base.lua

@@ -75,7 +75,7 @@ end
 
 
 function ZX_BASE.date2time(self, date)
--- function date2time(date)
+  -- function date2time(date)
   local time
   local regex
   local y, m, d, H, M, S
@@ -97,4 +97,57 @@ function ZX_BASE.date2time(self, date)
   return time
 end
 
+
+
+local require = require
+local ngx_re_find = ngx.re.find
+local lrucache = require "resty.lrucache"
+local resolver = require "resty.dns.resolver"
+local cache_storage = lrucache.new(200)
+
+local function _is_addr(hostname)
+  return ngx_re_find(hostname, [[\d+?\.\d+?\.\d+?\.\d+$]], "jo")
+end
+
+function ZX_BASE._get_addr(self,hostname)
+  _read_dns_servers_from_resolv_file()
+
+  if _is_addr(hostname) then
+    return hostname, hostname
+  end
+
+  local addr = cache_storage:get(hostname)
+
+  if addr then
+    return addr, hostname
+  end
+
+  local r, err = resolver:new({
+      nameservers = _G._dns_servers,
+      retrans = 5,  -- 5 retransmissions on receive timeout
+      timeout = 2000,  -- 2 sec
+  })
+
+  if not r then
+    return nil, hostname
+  end
+
+  local answers, err = r:query(hostname, {qtype = r.TYPE_A})
+
+  if not answers or answers.errcode then
+    return nil, hostname
+  end
+
+  for i, ans in ipairs(answers) do
+    if ans.address then
+      cache_storage:set(hostname, ans.address, 300)
+      return ans.address, hostname
+    end
+  end
+
+  return nil, hostname
+end
+
+
+
 return ZX_BASE

nginx/lua/luainit/init.lua

@@ -45,6 +45,45 @@ function _G.loadmod(namespace)
   error(module, 2)
 end
 
+local pcall = pcall
+local io_open = io.open
+local ngx_re_gmatch = ngx.re.gmatch
+local json = require ("cjson")
+
+local ok, new_tab = pcall(require, "table.new")
+
+if not ok then
+  new_tab = function (narr, nrec) return {} end
+end
+
+_G._dns_servers = new_tab(5, 0)
+
+local function _read_file_data(path)
+  local f, err = io_open(path, 'r')
+
+  if not f or err then
+    return nil, err
+  end
+
+  local data = f:read('*all')
+  f:close()
+  return data, nil
+end
+
+function _G._read_dns_servers_from_resolv_file(self)
+  local text = _read_file_data('/etc/resolv.conf')
+
+  local captures, it, err
+  it, err = ngx_re_gmatch(text, [[^nameserver\s+(\d+?\.\d+?\.\d+?\.\d+$)]], "jomi")
+
+  for captures, err in it do
+    if not err then
+      _G._dns_servers[#_G._dns_servers + 1] = captures[1]
+    end
+  end
+end
+
+
 -- _G.fpath = string.format("/var/log/www/S_%s.log", os.date("%Y%m%d"))
 -- _G.f = io.open(_G.fpath, "a+")