diff --git a/spring-boot-demo-ratelimit-redis/README.md b/spring-boot-demo-ratelimit-redis/README.md new file mode 100644 index 0000000..b5fbfbe --- /dev/null +++ b/spring-boot-demo-ratelimit-redis/README.md @@ -0,0 +1,296 @@ +# spring-boot-demo-ratelimit-redis + +> 此 demo 主要演示了 Spring Boot 项目如何通过 AOP 结合 Redis 实现分布式限流，旨在保护 API 被恶意频繁访问的问题，是 `spring-boot-demo-ratelimit-guava` 的升级版。 + +## 1. 主要代码 + +### 1.1. pom.xml + +```xml + + + 4.0.0 + + spring-boot-demo-ratelimit-redis + 1.0.0-SNAPSHOT + jar + + spring-boot-demo-ratelimit-redis + Demo project for Spring Boot + + + com.xkcoding + spring-boot-demo + 1.0.0-SNAPSHOT + + + + UTF-8 + UTF-8 + 1.8 + + + + + org.springframework.boot + spring-boot-starter-web + + + + org.springframework.boot + spring-boot-starter-aop + + + + org.springframework.boot + spring-boot-starter-data-redis + + + + + org.apache.commons + commons-pool2 + + + + cn.hutool + hutool-all + + + + org.springframework.boot + spring-boot-starter-test + test + + + + org.projectlombok + lombok + true + + + + + spring-boot-demo-ratelimit-redis + + + org.springframework.boot + spring-boot-maven-plugin + + + + + +``` + +### 1.2. 限流注解 + +```java +/** + *

+ * 限流注解，添加了 {@link AliasFor} 必须通过 {@link AnnotationUtils} 获取，才会生效 + *

+ * + * @author yangkai.shen + * @date Created in 2019/9/30 10:31 + * @see AnnotationUtils + */ +@Target(ElementType.METHOD) +@Retention(RetentionPolicy.RUNTIME) +@Documented +public @interface RateLimiter { + long DEFAULT_REQUEST = 10; + + /** + * max 最大请求数 + */ + @AliasFor("max") long value() default DEFAULT_REQUEST; + + /** + * max 最大请求数 + */ + @AliasFor("value") long max() default DEFAULT_REQUEST; + + /** + * 限流key + */ + String key() default ""; + + /** + * 超时时长，默认1分钟 + */ + long timeout() default 1; + + /** + * 超时时间单位，默认 分钟 + */ + TimeUnit timeUnit() default TimeUnit.MINUTES; +} +``` + +### 1.3. AOP处理限流 + +```java +/** + *

+ * 限流切面 + *

+ * + * @author yangkai.shen + * @date Created in 2019/9/30 10:30 + */ +@Slf4j +@Aspect +@Component +@RequiredArgsConstructor(onConstructor_ = @Autowired) +public class RateLimiterAspect { + private final static String SEPARATOR = ":"; + private final static String REDIS_LIMIT_KEY_PREFIX = "limit:"; + private final StringRedisTemplate stringRedisTemplate; + private final RedisScript limitRedisScript; + + @Pointcut("@annotation(com.xkcoding.ratelimit.redis.annotation.RateLimiter)") + public void rateLimit() { + + } + + @Around("rateLimit()") + public Object pointcut(ProceedingJoinPoint point) throws Throwable { + MethodSignature signature = (MethodSignature) point.getSignature(); + Method method = signature.getMethod(); + // 通过 AnnotationUtils.findAnnotation 获取 RateLimiter 注解 + RateLimiter rateLimiter = AnnotationUtils.findAnnotation(method, RateLimiter.class); + if (rateLimiter != null) { + String key = rateLimiter.key(); + // 默认用类名+方法名做限流的 key 前缀 + if (StrUtil.isBlank(key)) { + key = method.getDeclaringClass().getName()+StrUtil.DOT+method.getName(); + } + // 最终限流的 key 为 前缀 + IP地址 + // TODO: 此时需要考虑局域网多用户访问的情况，因此 key 后续需要加上方法参数更加合理 + key = key + SEPARATOR + IpUtil.getIpAddr(); + + long max = rateLimiter.max(); + long timeout = rateLimiter.timeout(); + TimeUnit timeUnit = rateLimiter.timeUnit(); + boolean limited = shouldLimited(key, max, timeout, timeUnit); + if (limited) { + throw new RuntimeException("手速太快了，慢点儿吧~"); + } + } + + return point.proceed(); + } + + private boolean shouldLimited(String key, long max, long timeout, TimeUnit timeUnit) { + // 最终的 key 格式为： + // limit:自定义key:IP + // limit:类名.方法名:IP + key = REDIS_LIMIT_KEY_PREFIX + key; + // 统一使用单位毫秒 + long ttl = timeUnit.toMillis(timeout); + // 当前时间毫秒数 + long now = Instant.now().toEpochMilli(); + long expired = now - ttl; + // 注意这里必须转为 String,否则会报错 java.lang.Long cannot be cast to java.lang.String + Long executeTimes = stringRedisTemplate.execute(limitRedisScript, Collections.singletonList(key), now + "", ttl + "", expired + "", max + ""); + if (executeTimes != null) { + if (executeTimes == 0) { + log.error("【{}】在单位时间 {} 毫秒内已达到访问上限，当前接口上限 {}", key, ttl, max); + return true; + } else { + log.info("【{}】在单位时间 {} 毫秒内访问 {} 次", key, ttl, executeTimes); + return false; + } + } + return false; + } +} +``` + +### 1.4. lua 脚本 + +```lua +-- 下标从 1 开始 +local key = KEYS[1] +local now = tonumber(ARGV[1]) +local ttl = tonumber(ARGV[2]) +local expired = tonumber(ARGV[3]) +-- 最大访问量 +local max = tonumber(ARGV[4]) + +-- 清除过期的数据 +-- 移除指定分数区间内的所有元素，expired 即已经过期的 score +-- 根据当前时间毫秒数 - 超时毫秒数，得到过期时间 expired +redis.call('zremrangebyscore', key, 0, expired) + +-- 获取 zset 中的当前元素个数 +local current = tonumber(redis.call('zcard', key)) +local next = current + 1 + +if next > max then + -- 达到限流大小 返回 0 + return 0; +else + -- 往 zset 中添加一个值、得分均为当前时间戳的元素，[value,score] + redis.call("zadd", key, now, now) + -- 每次访问均重新设置 zset 的过期时间，单位毫秒 + redis.call("pexpire", key, ttl) + return next +end +``` + +### 1.5. 接口测试 + +```java +/** + *

+ * 测试 + *

+ * + * @author yangkai.shen + * @date Created in 2019/9/30 10:30 + */ +@Slf4j +@RestController +public class TestController { + + @RateLimiter(value = 5) + @GetMapping("/test1") + public Dict test1() { + log.info("【test1】被执行了。。。。。"); + return Dict.create().set("msg", "hello,world!").set("description", "别想一直看到我，不信你快速刷新看看~"); + } + + @GetMapping("/test2") + public Dict test2() { + log.info("【test2】被执行了。。。。。"); + return Dict.create().set("msg", "hello,world!").set("description", "我一直都在，卟离卟弃"); + } + + @RateLimiter(value = 2, key = "测试自定义key") + @GetMapping("/test3") + public Dict test3() { + log.info("【test3】被执行了。。。。。"); + return Dict.create().set("msg", "hello,world!").set("description", "别想一直看到我，不信你快速刷新看看~"); + } +} +``` + +### 1.6. 其余代码参见 demo + +## 2. 测试 + +- 触发限流时控制台打印 + +![image-20190930155856711](assets/image-20190930155856711.png) + +- 触发限流的时候 Redis 的数据 + +![image-20190930155735300](assets/image-20190930155735300.png) + +## 3. 参考 + +- [mica-plus-redis 的分布式限流实现](https://github.com/lets-mica/mica/tree/master/mica-plus-redis) +- [Java并发：分布式应用限流 Redis + Lua 实践](https://segmentfault.com/a/1190000016042927) \ No newline at end of file diff --git a/spring-boot-demo-ratelimit-redis/assets/image-20190930155735300.png b/spring-boot-demo-ratelimit-redis/assets/image-20190930155735300.png new file mode 100644 index 0000000..2018be7 Binary files /dev/null and b/spring-boot-demo-ratelimit-redis/assets/image-20190930155735300.png differ diff --git a/spring-boot-demo-ratelimit-redis/assets/image-20190930155856711.png b/spring-boot-demo-ratelimit-redis/assets/image-20190930155856711.png new file mode 100644 index 0000000..31f2f6f Binary files /dev/null and b/spring-boot-demo-ratelimit-redis/assets/image-20190930155856711.png differ