Openresty 根据 IP 限流

配置：

http {
lua_shared_dict my_limit_req_store 100m;

server {
location / {
access_by_lua_block {

local limit_req = require “resty.limit.req”

— limit the requests under 200 req/sec with a burst of 100 req/sec,
— that is, we delay requests under 300 req/sec and above 200
— req/sec, and reject any requests exceeding 300 req/sec.
— 200req/sec 以下不限流，300req/sec 拒绝，200~300req/sec 延迟

local lim, err = limit_req.new(“my_limit_req_store”, 200, 100)
if not lim then
ngx.log(ngx.ERR,
“failed to instantiate a resty.limit.req object: “, err)
return ngx.exit(500)
end

— the following call must be per-request.
— here we use the remote (IP) address as the limiting key
— 限制条件为 ip
local key = ngx.var.binary_remote_addr
— 300 以上，err 为 rejected,200~300 err 为超过 200 的额外请求数，delay 为延迟时间
local delay, err = lim:incoming(key, true)
if not delay then
if err == “rejected” then
return ngx.exit(503)
end
ngx.log(ngx.ERR, “failed to limit req: “, err)
return ngx.exit(500)
end

if delay >= 0.001 then
— the 2nd return value holds the number of excess requests
— per second for the specified key. for example, number 31
— means the current request rate is at 231 req/sec for the
— specified key.
local excess = err

— the request exceeding the 200 req/sec but below 300 req/sec,
— so we intentionally delay it here a bit to conform to the
— 200 req/sec rate.
ngx.sleep(delay)
end
}

# content handler goes here. if it is content_by_lua, then you can
# merge the Lua code above in access_by_lua into your content_by_lua’s
# Lua handler to save a little bit of CPU time.
}
}
}