# 由于公共庫中找不到openresty，所以需要添加openresty的源倉庫
yum-config-manager --add-repo https://openresty.org/package/centos/openresty.repo

# 注意，如果上面命令提示不存在,那就先安裝一下
yum install -y yum-utils

# 安裝openresty
yum install -y openresty
# 安裝OpenResty管理工具，幫助我們安裝第三方的Lua模塊
yum install -y openresty-opm

worker_processes 1;
events {
    worker_connections 1024;
}
http {
    server{
        listen 999;
        server_name  localhost;
        location /mapbox/ {
            access_by_lua_file "/usr/local/openresty/nginx/lua_script/rule.lua";
            proxy_pass https://api.mapbox.com/;
            proxy_ssl_server_name on;
        }
    }
}

-- 其實這兩個值可以從redis取  甚至可以給每個qrcode設(shè)置單獨的速率和容積
-- 但如果想監(jiān)聽桶的狀態(tài)  需要持續(xù)的請求， 只有每次請求后才重新計算并更新桶狀態(tài) 否則桶狀態(tài)不變
local tokens_per_second = 0.2  -- 生成速率 /s
local max_tokens = 10  -- 最大溶劑
local current_time = ngx.now()
local path = ngx.var.uri
local redis_key = "map_request_limitation"
local redis_key_white_list = "map_request_white_list"
local client_ip = ngx.var.remote_addr
-- local redis_key = "path:" .. path
-- 連接Redis
local redis = require "resty.redis"
local red = redis:new()
red:set_timeout(1000)
local ok, err = red:connect("127.0.0.1", 6379)
if not ok then
    ngx.log(ngx.ERR, "Redis連接失敗: ", err)
    return ngx.exit(500)
end
-- 權(quán)限校驗
local res, err = red:auth("123456")
if not res then
    ngx.say("failed to authenticate: ", err)
    return
end
-- 發(fā)送 Lua 腳本（保證redis原子性操作）
local script = [[
    local redis_key = KEYS[1]
    local redis_white_list_key = KEYS[2]
    local tokens_per_second = tonumber(ARGV[1])
    local max_tokens = tonumber(ARGV[2])
    local current_time = tonumber(ARGV[3])
    local client_ip = ARGV[4]
    -- ip是否存在列表中
    local is_in_whitelist, err = redis.call('sismember', redis_white_list_key, client_ip)
    if is_in_whitelist == 1 then
        return 1
    end
    -- 獲取上次訪問時間和令牌數(shù)量
    local res = redis.call('HMGET', redis_key, 'last_access_time', 'tokens')
    local last_access_time
    local last_tokens
    if res[1] and res[2] then
	last_tokens = res[2]
	last_access_time =  res[1]
    end
    -- 計算時間間隔
    local time_passed = current_time - (tonumber(last_access_time) or 0)
    -- 計算新的令牌數(shù)量
    last_tokens = last_tokens and tonumber(last_tokens) or max_tokens
    local new_tokens = math.min(max_tokens, last_tokens + time_passed * tokens_per_second)
    -- 判斷令牌數(shù)量是否足夠
    if new_tokens >= 1 then
        -- 消耗令牌
        redis.call('HMSET', redis_key, 'last_access_time', current_time, 'tokens', new_tokens - 1)
        return 1
    else
        return 0
    end
]]
-- 執(zhí)行腳本
local result = red:eval(script, 2, redis_key, redis_key_white_list,tokens_per_second, max_tokens,current_time,client_ip)
if result == 1 then
    -- 成功
    ngx.log(ngx.INFO, "成功")
else
    -- 令牌不足
    ngx.status = ngx.HTTP_TOO_MANY_REQUESTS
    ngx.say("OVERLOAD?。。?！",result)
    return ngx.exit(ngx.HTTP_TOO_MANY_REQUESTS)
end
-- 返還redis連接到連接池
local ok, err = red:set_keepalive(10000, 100)
if not ok then
    ngx.log(ngx.ERR, err)
end