Nginx：lua-resty-http实现一致性hash负载均衡。

有针对性的对url进行一致性hash 定向负载到后端Nginx，提高Nginx缓存系统命中率。

ocal http = require("resty.http")  
local httpc = http.new()  

local hosts = {"192.168.1.101","192.168.1.102"}

local item_id= ngx.var.arg_id

local id_hash = ngx.crc32_long(item_id)
local index = (id_hash % 2) +1
  
local resp, err = httpc:request_uri("http://"..hosts[index], {  
    method = "GET",  
    path = "/sogou?query=resty.http",  
    headers = {  
        ["User-Agent"] = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.111 Safari/537.36"  
    }  
})  
  
if not resp then  
    ngx.say("request error :", err)  
    return  
end  
  
 
ngx.say(resp.body)  
  
httpc:close()