user nobody;
worker_processes  1;
events {
lua降級代碼：/etc/nginx/lua/goods_list_advert.lua
 worker_connections  1024;
}
http {
 lua_package_path "/usr/share/lua/5.1/lua-resty-redis/lib/?.lua;;/usr/share/lua/5.1/lua-
resty-redis-cluster/lib/resty‘7/?.lua;;";
 lua_package_cpath "/usr/share/lua/5.1/lua-resty-redis-cluster/lib/libredis_slot.so;;";
 include    mime.types;
 default_type application/octet-stream;
 sendfile    on;
 keepalive_timeout  65;
 server {
   listen    80;
   server_name  127.0.0.1;
   server_name  192.168.232.100;
    #獲取廣告推薦數據
 location /goods_list_advert {
   default_type 'application/x-javascript;charset=utf-8';
     content_by_lua_file /etc/nginx/lua/goods_list_advert.lua;
   }
    #從服務層+mysql獲取數據
   location /goods_list_advert_from_data {
     default_type 'application/x-javascript;charset=utf-8';
     content_by_lua '
       ngx.say("從服務層+mysql獲取數據")
      ';
   }
 }
}

--獲取get或post參數--------------------

local request_method = ngx.var.request_method
local args = nil
local param = nil
--獲取參數的值
if "GET" == request_method then
    args = ngx.req.get_uri_args()
elseif "POST" == request_method then
    ngx.req.read_body()
    args = ngx.req.get_post_args()
end
sku_id = args["sku_id"]


--關閉redis的函數--------------------

local function close_redis(redis_instance)
    if not redis_instance then
        return
    end
    local ok,err = redis_instance:close();
    if not ok then
        ngx.say("close redis error : ",err);
    end
end


--連接redis--------------------

local redis = require("resty.redis");
--local redis = require "redis"
-- 創(chuàng)建一個redis對象實例。在失敗，返回nil和描述錯誤的字符串的情況下
local redis_instance = redis:new();
--設置后續(xù)操作的超時（以毫秒為單位）保護，包括connect方法
redis_instance:set_timeout(1000)
--建立連接
local ip = '127.0.0.1'
local port = 6379
--嘗試連接到redis服務器正在偵聽的遠程主機和端口
local ok,err = redis_instance:connect(ip,port)
if not ok then
    ngx.say("connect redis error : ",err)
    return close_redis(redis_instance);
end


--從redis里面讀取開關--------------------

local key = "level_goods_list_advert"
local switch, err = redis_instance:get(key)
if not switch then
    ngx.say("get msg error : ", err)
    return close_redis(redis_instance)
end


--得到的開關為空處理--------------------

if switch == ngx.null then
    switch = "FROM_DATA"  --比如默認值
end


--當開關是要從服務中獲取數據時--------------------
if "FROM_DATA" == switch then
    ngx.exec('/goods_list_advert_from_data');

--當開關是要從緩存中獲取數據時--------------------
elseif "FROM_CACHE" == switch then

    local resp, err = redis_instance:get("nihao")
    ngx.say(resp)

--當開關是要從靜態(tài)資源中獲取數據時--------------------
elseif "FROM_STATIC" == switch then

    ngx.header.content_type="application/x-javascript;charset=utf-8"
    local file = "/etc/nginx/html/goods_list_advert.json"
    local f = io.open(file, "rb")
    local content = f:read("*all")
    f:close()
    ngx.print(content)

--當開關是要停掉數據獲取時--------------------
elseif "SHUT_DOWN" == switch then

    ngx.say('no data')
end

[
{
“goods_id”:“1”,
“goods_name”:“測試1”,
},
{
“goods_id”:“2”,
“goods_name”:“測試2”,
}
]

--判斷錯誤的響應，并進行計數， 后續(xù)便可以參考這個數值進行降級
if tonumber(ngx.var.status) == 200 then
  ngx.say(ngx.var.status)
  ngx.log(ngx.ERR,"upstream reponse status is " .. ngx.var.status .. ",please notice it")
  local error_count, err = redis_instance:get("error_count_goods_list_advert")
  --得到的數據為空處理
  if error_count == ngx.null then
    error_count = 0
  end
  error_count = error_count + 1
  --統(tǒng)計錯誤次數到error_count_goods_list_advert
  local resp,err = redis_instance:set("error_count_goods_list_advert",error_count)
  if not resp then
    ngx.say("set msg error : ",err)
    return close_redis(redis_instance)
  end
end