小张笔记

nginx_lua实现动态黑名单

祈雨的博客

2018-12-23

# 介绍

通过nginx+lua+redis可以实现nginx动态从redis读取需要拒绝的ip黑名单列表，并拒绝黑名单ip的访问请求。

其中redis中的ip黑名单列表既可以人工后台手动添加，也可以用类似logstash+elasticsearch的组合，实现logstash实时读取nginx的访问日志access.log，elasticsearch储存并聚合访问日志中的访问记录，再由一个分析程序定时统计分析访问记录后判断出要加入黑名单的ip，然后将ip储存到redis中的ip黑名单列表。

# nginx配置

http {
    ...
    lua_shared_dict forbidden_list 5m;
    
    location /lua {
        # lua_code_cache off;
        access_by_lua_file conf/lua/forbidden_list.lua;
        default_type 'text/html';
        content_by_lua 'ngx.say("hello world")';
    }
}

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# lua配置

local redis = require("resty.redis")
local ngx_log = ngx.log
local ngx_ERR = ngx.ERR
local ngx_INFO = ngx.INFO
local ngx_exit = ngx.exit
local ngx_var = ngx.var

-- 黑名单缓存60秒
local cache_idle = 60
local forbidden_list = ngx.shared.forbidden_list


local function close_redis(red)
	if not red then
		return
	end
	-- 释放连接(连接池实现)
	local pool_max_idle_time = 10000 -- 毫秒
	local pool_size = 100  -- 连接池大小
	local ok, err = red:set_keepalive(pool_max_idle_time, pool_size)
	
	if not ok then
		ngx_log(ngx_ERR, "set redis keepalive error : ", err)
	end
end

-- 从redis获取ip黑名单列表
local function get_forbidden_list()
	local red = redis:new()
	red:set_timeout(1000)
	local ip = "127.0.0.1"
	local port = 6379
	local password = "password"
	local ok, err = red:connect(ip, port)
	if not ok then
		ngx_log(ngx_ERR, "connect to redis error : ", err)
		close_redis(red)
		return
	end
	
	local res, err = red:auth(password)
    if not res then
        ngx_log(ngx_ERR, "failed to authenticate: ", err)
		close_redis(red)
        return
    end
	
	local resp, err = red:smembers("forbidden_list")
	if not resp then
		ngx_log(ngx_ERR, "get redis connect error : ", err)
		close_redis(red)
		return
	end
	-- 得到的数据为空处理
	if resp == ngx.null then
		resp = nil
	end
	close_redis(red)
	
	return resp
end

-- 刷新黑名单
local function reflush_forbidden_list()
	local current_time = ngx.now()
	local last_update_time = forbidden_list:get("last_update_time");
	
	if last_update_time == nil or last_update_time < (current_time - cache_idle) then
		local new_forbidden_list = get_forbidden_list();
		if not new_forbidden_list then
			return
		end
		
		forbidden_list:flush_all()
		for i, forbidden_ip in ipairs(new_forbidden_list) do
			forbidden_list:set(forbidden_ip, true);
		end
		forbidden_list:set("last_update_time", current_time);
	end
end


reflush_forbidden_list()
local ip = ngx_var.remote_addr
if forbidden_list:get(ip) then
	ngx_log(ngx_INFO, "forbidden ip refused access : ", ip)
	return ngx_exit(ngx.HTTP_FORBIDDEN)
end

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# redis修改黑名单

# 添加黑名单

SADD forbidden_list "127.0.0.1"

# 移除黑名单

SREM forbidden_list "127.0.0.1"

# 效果

[root@localhost ~]# curl http://localhost/lua
<html>
<head><title>403 Forbidden</title></head>
<body bgcolor="white">
<center><h1>403 Forbidden</h1></center>
<hr><center>openresty/1.13.6.1</center>
</body>
</html>
[root@localhost ~]# curl http://localhost/lua
hello world

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# 日志

2018/12/23 13:10:47 [info] 4416#0: *56 [lua] forbidden_list.lua:86: forbidden ip refused access : 127.0.0.1, client: 127.0.0.1, server: localhost, request: "GET /lua HTTP/1.1", host: "localhost"