基于Redis+Lua脚本实现分布式限流组件封装的方法

   org.springframework.bootspring-boot-starter-data-redis org.springframework.bootspring-boot-starter-aop com.google.guavaguava18.0

 -- -- Created by IntelliJ IDEA. -- User: 寒夜 -- -- 获取方法签名特征 local methodKey = KEYS[1] redis.log(redis.LOG_DEBUG, 'key is', methodKey) -- 调用脚本传入的限流大小 local limit = tonumber(ARGV[1]) -- 获取当前流量大小 local count = tonumber(redis.call('get', methodKey) or "0") -- 是否超出限流阈值 if count + 1 > limit then -- 拒绝服务访问 return false else -- 没有超过阈值 -- 设置当前访问的数量+1 redis.call("INCRBY", methodKey, 1) -- 设置过期时间 redis.call("EXPIRE", methodKey, 1) -- 放行 return true end

 package com.imooc.springcloud; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.core.io.ClassPathResource; import org.springframework.data.redis.connection.RedisConnectionFactory; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.StringRedisTemplate; import org.springframework.data.redis.core.script.DefaultRedisScript; /** * @author 寒夜 */ @Configuration public class RedisConfiguration { @Bean public RedisTemplate redisTemplate( RedisConnectionFactory factory) { return new StringRedisTemplate(factory); } @Bean public DefaultRedisScript loadRedisScript() { DefaultRedisScript redisScript = new DefaultRedisScript(); redisScript.setLocation(new ClassPathResource("ratelimiter.lua")); redisScript.setResultType(java.lang.Boolean.class); return redisScript; } }

 package com.hy.annotation; import java.lang.annotation.*; /** * @author 寒夜 */ @Target({ElementType.METHOD}) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface AccessLimiter { int limit(); String methodKey() default ""; }

 package com.hy.annotation; import com.google.common.collect.Lists; import lombok.extern.slf4j.Slf4j; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; import org.aspectj.lang.annotation.Pointcut; import org.aspectj.lang.reflect.MethodSignature; import org.springframework.data.redis.core.StringRedisTemplate; import org.springframework.data.redis.core.script.RedisScript; import org.springframework.stereotype.Component; import org.springframework.util.StringUtils; import java.lang.reflect.Method; import java.util.Arrays; import java.util.stream.Collectors; /** * @author 寒夜 */ @Slf4j @Aspect @Component public class AccessLimiterAspect { private final StringRedisTemplate stringRedisTemplate; private final RedisScript rateLimitLua; public AccessLimiterAspect(StringRedisTemplate stringRedisTemplate, RedisScript rateLimitLua) { this.stringRedisTemplate = stringRedisTemplate; this.rateLimitLua = rateLimitLua; } @Pointcut(value = "@annotation(com.hy.annotation.AccessLimiter)") public void cut() { log.info("cut"); } @Before("cut()") public void before(JoinPoint joinPoint) { // 1. 获得方法签名，作为method Key MethodSignature signature = (MethodSignature) joinPoint.getSignature(); Method method = signature.getMethod(); AccessLimiter annotation = method.getAnnotation(AccessLimiter.class); if (annotation == null) { return; } String key = annotation.methodKey(); int limit = annotation.limit(); // 如果没设置methodkey, 从调用方法签名生成自动一个key if (StringUtils.isEmpty(key)) { Class[] type = method.getParameterTypes(); key = method.getClass() + method.getName(); if (type != null) { String paramTypes = Arrays.stream(type) .map(Class::getName) .collect(Collectors.joining(",")); log.info("param types: " + paramTypes); key += "#" + paramTypes; } } // 2. 调用Redis boolean acquired = stringRedisTemplate.execute( rateLimitLua, // Lua script的真身 Lists.newArrayList(key), // Lua脚本中的Key列表 Integer.toString(limit) // Lua脚本Value列表 ); if (!acquired) { log.error("your access is blocked, key={}", key); throw new RuntimeException("Your access is blocked"); } } }

 spring: redis: host: 192.168.0.218 port: 6379 password: 123456 database: 0 application: name: ratelimiter-test server: port: 10087

 package com.hy; import com.hy.annotation.AccessLimiter; import lombok.extern.slf4j.Slf4j; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; /** * @author 寒夜 */ @RestController @Slf4j public class Controller { private final com.hy.AccessLimiter accessLimiter; public Controller(com.hy.AccessLimiter accessLimiter) { this.accessLimiter = accessLimiter; } @GetMapping("test") public String test() { accessLimiter.limitAccess("ratelimiter-test", 3); return "success"; } // 提醒！ 注意配置扫包路径（com.hy路径不同） @GetMapping("test-annotation") @AccessLimiter(limit = 1) public String testAnnotation() { return "success"; } }