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spring cloud gateway 网关限流

 

 

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限流算法：令牌桶

 

                  

以均匀的速率向令牌桶中添加令牌，令牌数量达到最大后，数量不再增加；

对客户端的请求按key进行分组，请求获得对应令牌桶中的令牌后，发送到后端处理；

如果不能获得令牌，则等待或者服务降级

 

使用令牌同算法可以有效的应对短时间的大量突发请求

 

 

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相关类及接口

 

RateLimiter：限流接口

public interface RateLimiter<C> extends StatefulConfigurable<C> {Mono<RateLimiter.Response> isAllowed(String routeId, String id);}

 

RedisRateLimiter：redis限流实现类

@ConfigurationProperties("spring.cloud.gateway.redis-rate-limiter")
public class RedisRateLimiter extends AbstractRateLimiter<RedisRateLimiter.Config> implements ApplicationContextAware {public static final String CONFIGURATION_PROPERTY_NAME = "redis-rate-limiter";public static final String REDIS_SCRIPT_NAME = "redisRequestRateLimiterScript";public static final String REMAINING_HEADER = "X-RateLimit-Remaining";public static final String REPLENISH_RATE_HEADER = "X-RateLimit-Replenish-Rate";public static final String BURST_CAPACITY_HEADER = "X-RateLimit-Burst-Capacity";private Log log = LogFactory.getLog(this.getClass());private ReactiveStringRedisTemplate redisTemplate;private RedisScript<List<Long>> script;private AtomicBoolean initialized = new AtomicBoolean(false);private RedisRateLimiter.Config defaultConfig;private boolean includeHeaders = true;private String remainingHeader = "X-RateLimit-Remaining";private String replenishRateHeader = "X-RateLimit-Replenish-Rate";private String burstCapacityHeader = "X-RateLimit-Burst-Capacity";public Mono<Response> isAllowed(String routeId, String id) {if (!this.initialized.get()) {throw new IllegalStateException("RedisRateLimiter is not initialized");} else {RedisRateLimiter.Config routeConfig = this.loadConfiguration(routeId);int replenishRate = routeConfig.getReplenishRate();int burstCapacity = routeConfig.getBurstCapacity();try {List<String> keys = getKeys(id);List<String> scriptArgs = Arrays.asList(replenishRate + "", burstCapacity + "", Instant.now().getEpochSecond() + "", "1");Flux<List<Long>> flux = this.redisTemplate.execute(this.script, keys, scriptArgs);return flux.onErrorResume((throwable) -> {return Flux.just(Arrays.asList(1L, -1L));}).reduce(new ArrayList(), (longs, l) -> {longs.addAll(l);return longs;}).map((results) -> {boolean allowed = (Long)results.get(0) == 1L;Long tokensLeft = (Long)results.get(1);Response response = new Response(allowed, this.getHeaders(routeConfig, tokensLeft));if (this.log.isDebugEnabled()) {this.log.debug("response: " + response);}return response;});} catch (Exception var9) {this.log.error("Error determining if user allowed from redis", var9);return Mono.just(new Response(true, this.getHeaders(routeConfig, -1L)));}}}//判断是否通过请求RedisRateLimiter.Config loadConfiguration(String routeId) {RedisRateLimiter.Config routeConfig = (RedisRateLimiter.Config)this.getConfig().getOrDefault(routeId, this.defaultConfig);if (routeConfig == null) {routeConfig = (RedisRateLimiter.Config)this.getConfig().get("defaultFilters");}if (routeConfig == null) {throw new IllegalArgumentException("No Configuration found for route " + routeId + " or defaultFilters");} else {return routeConfig;}}//加载限流配置****************
内部类@Validatedpublic static class Config {@Min(1L)private int replenishRate;         //每秒处理的请求数@Min(1L)private int burstCapacity = 1;     //每秒最大处理的请求数，一般将此项设置为与replenishRate相同public Config() {

 

KeyResolver：限流的key接口

public interface KeyResolver {Mono<String> resolve(ServerWebExchange exchange);
}

 

PrincipalNameKeyResolver：默认根据用户名进行限流

public class PrincipalNameKeyResolver implements KeyResolver {public static final String BEAN_NAME = "principalNameKeyResolver";public PrincipalNameKeyResolver() {}public Mono<String> resolve(ServerWebExchange exchange) {return exchange.getPrincipal().map(Principal::getName).switchIfEmpty(Mono.empty());}
}

 

 

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示例

 

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配置文件

 

application.yml

spring:cloud:gateway:routes:- id: redis-rate-limiteruri: http://localhost:8080predicates:- Path=/hello/hello2filters:- StripPrefix=1- name: RequestRateLimiterargs:key-resolver: "#{@uriKeyResolver}"redis-rate-limiter.replenishRate: 5redis-rate-limiter.burstCapacity: 10redis:host: 192.168.57.120port: 6379password: 123456

 

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限流key配置

 

URIKeyResolver

@Component("uriKeyResolver")
public class URIKeyResolver implements KeyResolver {@Overridepublic Mono<String> resolve(ServerWebExchange exchange) {return Mono.just(exchange.getRequest().getURI().getPath());}
}

 

 

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限流测试