详解Spring Cloud Gateway 限流操作

<dependency>

  <groupid>org.springframework.boot</groupid>

  <artifactid>spring-boot-starter-data-redis-reactive</artifactid>

</dependency>

@bean

public keyresolver ipkeyresolver() {

  return exchange -> mono.just(exchange.getrequest().getremoteaddress().gethostname());

}

@bean

keyresolver userkeyresolver() {

  return exchange -> mono.just(exchange.getrequest().getqueryparams().getfirst( "userid" ));

}

@bean

keyresolver apikeyresolver() {

  return exchange -> mono.just(exchange.getrequest().getpath().value());

}

server:

  port: 8084

spring:

  redis:

  host: 127.0 . 0.1

  port: 6379

  cloud:

  gateway:

   routes:

   - id: fsh-house

   uri: lb: //fsh-house

   predicates:

   - path=/house/**

   filters:

   - name: requestratelimiter

    args:

    redis-rate-limiter.replenishrate: 10

    redis-rate-limiter.burstcapacity: 20

    key-resolver: "#{@ipkeyresolver}"

// routeid也就是我们的fsh-house，id就是限流的key，也就是localhost。

public mono<response> isallowed(string routeid, string id) {

  // 会判断redisratelimiter是否初始化了

  if (! this .initialized.get()) {

   throw new illegalstateexception( "redisratelimiter is not initialized" );

  }

  // 获取routeid对应的限流配置

  config routeconfig = getconfig().getordefault(routeid, defaultconfig);

  if (routeconfig == null ) {

   throw new illegalargumentexception( "no configuration found for route " + routeid);

  }

  // 允许用户每秒做多少次请求

  int replenishrate = routeconfig.getreplenishrate();

  // 令牌桶的容量，允许在一秒钟内完成的最大请求数

  int burstcapacity = routeconfig.getburstcapacity();

  try {

   // 限流key的名称（request_rate_limiter.{localhost}.timestamp，request_rate_limiter.{localhost}.tokens）

   list<string> keys = getkeys(id);

   // the arguments to the lua script. time() returns unixtime in seconds.

   list<string> scriptargs = arrays.aslist(replenishrate + "" , burstcapacity + "" ,

     instant.now().getepochsecond() + "" , "1" );

   // allowed, tokens_left = redis.eval(script, keys, args)

   // 执行lua脚本

   flux<list< long >> flux = this .redistemplate.execute( this .script, keys, scriptargs);

     // .log("redisratelimiter", level.finer);

   return flux.onerrorresume(throwable -> flux.just(arrays.aslist(1l, -1l)))

     .reduce( new arraylist< long >(), (longs, l) -> {

      longs.addall(l);

      return longs;

     }) .map(results -> {

      boolean allowed = results.get( 0 ) == 1l;

      long tokensleft = results.get( 1 );

      response response = new response(allowed, getheaders(routeconfig, tokensleft));

      if (log.isdebugenabled()) {

       log.debug( "response: " + response);

      }

      return response;

     });

  }

  catch (exception e) {

   log.error( "error determining if user allowed from redis" , e);

  }

  return mono.just( new response( true , getheaders(routeconfig, -1l)));

}

local tokens_key = keys[ 1 ]

local timestamp_key = keys[ 2 ]

--redis.log(redis.log_warning, "tokens_key " .. tokens_key)

local rate = tonumber(argv[ 1 ])

local capacity = tonumber(argv[ 2 ])

local now = tonumber(argv[ 3 ])

local requested = tonumber(argv[ 4 ])

local fill_time = capacity/rate

local ttl = math.floor(fill_time* 2 )

--redis.log(redis.log_warning, "rate " .. argv[ 1 ])

--redis.log(redis.log_warning, "capacity " .. argv[ 2 ])

--redis.log(redis.log_warning, "now " .. argv[ 3 ])

--redis.log(redis.log_warning, "requested " .. argv[ 4 ])

--redis.log(redis.log_warning, "filltime " .. fill_time)

--redis.log(redis.log_warning, "ttl " .. ttl)

local last_tokens = tonumber(redis.call( "get" , tokens_key))

if last_tokens == nil then

  last_tokens = capacity

end

--redis.log(redis.log_warning, "last_tokens " .. last_tokens)

local last_refreshed = tonumber(redis.call( "get" , timestamp_key))

if last_refreshed == nil then

  last_refreshed = 0

end

--redis.log(redis.log_warning, "last_refreshed " .. last_refreshed)

local delta = math.max( 0 , now-last_refreshed)

local filled_tokens = math.min(capacity, last_tokens+(delta*rate))

local allowed = filled_tokens >= requested

local new_tokens = filled_tokens

local allowed_num = 0

if allowed then

  new_tokens = filled_tokens - requested

  allowed_num = 1

end

--redis.log(redis.log_warning, "delta " .. delta)

--redis.log(redis.log_warning, "filled_tokens " .. filled_tokens)

--redis.log(redis.log_warning, "allowed_num " .. allowed_num)

--redis.log(redis.log_warning, "new_tokens " .. new_tokens)

redis.call( "setex" , tokens_key, ttl, new_tokens)

redis.call( "setex" , timestamp_key, ttl, now)

return { allowed_num, new_tokens }