基于Redis+Lua脚本实现分布式限流组件封装的方法

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在数据库实战开发的过程中，我们经常会遇到一些这样那样的问题，然后要卡好半天，等问题解决了才发现原来一些细节知识点还是没有掌握好。今天golang学习网就整理分享《基于Redis+Lua脚本实现分布式限流组件封装的方法》，聊聊Redislua脚本、分布式限流组件，希望可以帮助到正在努力赚钱的你。

创建限流组件项目

pom.xml文件中引入相关依赖

 
   
    
     
      org.springframework.boot
     
     
      spring-boot-starter-data-redis
     
    
    
     
      org.springframework.boot
     
     
      spring-boot-starter-aop
     
    
    
     
      com.google.guava
     
     
      guava
     
     
      18.0
     
    
   

在resources目录下创建lua脚本  ratelimiter.lua

--
-- 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

创建RedisConfiguration 类

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;
 }
 
}
   

创建一个自定义注解 

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 "";
 
}

创建一个切入点

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"); } } }
    
   

创建测试项目

pom.xml中引入组件

application.yml配置

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

创建controller

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";
 }
 
}

开始测试，快速点击结果如下