使用AOP+redis+lua做方法限流的实现

Malinda ·

更新时间:2024-09-20

· 1066 次阅读

需求

实现方式

源码

Limit 注解

LimitKey

LimitType

RedisLimiterHelper

LimitInterceptor

TestService

需求

公司里使用OneByOne的方式删除数据，为了防止一段时间内删除数据过多，让我这边做一个接口限流，超过一定阈值后报异常，终止删除操作。

实现方式

创建自定义注解 @limit 让使用者在需要的地方配置 count(一定时间内最多访问次数)、 period(给定的时间范围)，也就是访问频率。然后通过LimitInterceptor拦截方法的请求，通过 redis+lua 脚本的方式，控制访问频率。

源码 Limit 注解

用于配置方法的访问频率count、period

import javax.validation.constraints.Min;
import java.lang.annotation.*;
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface Limit {
    /**
     * key
     */
    String key() default "";
    /**
     * Key的前缀
     */
    String prefix() default "";
    /**
     * 一定时间内最多访问次数
     */
    @Min(1)
    int count();
    /**
     * 给定的时间范围 单位(秒)
     */
    @Min(1)
    int period();
    /**
     * 限流的类型(用户自定义key或者请求ip)
     */
    LimitType limitType() default LimitType.CUSTOMER;
}

LimitKey

用于标记参数，作为redis key值的一部分

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface LimitKey {
}

LimitType

枚举，redis key值的类型，支持自定义key和ip、methodName中获取key

public enum LimitType {
    /**
     * 自定义key
     */
    CUSTOMER,
    /**
     * 请求者IP
     */
    IP,
    /**
     * 方法名称
     */
    METHOD_NAME;
}

RedisLimiterHelper

初始化一个限流用到的redisTemplate Bean

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import java.io.Serializable;
@Configuration
public class RedisLimiterHelper {
    @Bean
    public RedisTemplate<String, Serializable> limitRedisTemplate(@Qualifier("defaultStringRedisTemplate") StringRedisTemplate redisTemplate) {
        RedisTemplate<String, Serializable> template = new RedisTemplate<String, Serializable>();
        template.setKeySerializer(new StringRedisSerializer());
        template.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        template.setConnectionFactory(redisTemplate.getConnectionFactory());
        return template;
    }
}

LimitInterceptor

使用 aop 的方式来拦截请求，控制访问频率

import com.google.common.collect.ImmutableList;
import com.yxt.qida.api.bean.service.xxv2.openapi.anno.Limit;
import com.yxt.qida.api.bean.service.xxv2.openapi.anno.LimitKey;
import com.yxt.qida.api.bean.service.xxv2.openapi.anno.LimitType;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
@Slf4j
@Aspect
@Configuration
public class LimitInterceptor {
    private static final String UNKNOWN = "unknown";
    private final RedisTemplate<String, Serializable> limitRedisTemplate;
    @Autowired
    public LimitInterceptor(RedisTemplate<String, Serializable> limitRedisTemplate) {
        this.limitRedisTemplate = limitRedisTemplate;
    }
    @Around("execution(public * *(..)) && @annotation(com.yxt.qida.api.bean.service.xxv2.openapi.anno.Limit)")
    public Object interceptor(ProceedingJoinPoint pjp) {
        MethodSignature signature = (MethodSignature) pjp.getSignature();
        Method method = signature.getMethod();
        Limit limitAnnotation = method.getAnnotation(Limit.class);
        LimitType limitType = limitAnnotation.limitType();
        int limitPeriod = limitAnnotation.period();
        int limitCount = limitAnnotation.count();
        /**
         * 根据限流类型获取不同的key ,如果不传我们会以方法名作为key
         */
        String key;
        switch (limitType) {
            case IP:
                key = getIpAddress();
                break;
            case CUSTOMER:
                key = limitAnnotation.key();
                break;
            case METHOD_NAME:
                String methodName = method.getName();
                key = StringUtils.upperCase(methodName);
                break;
            default:
                throw new RuntimeException("limitInterceptor - 无效的枚举值");
        }
        /**
         * 获取注解标注的 key，这个是优先级最高的，会覆盖前面的 key 值
         */
        Object[] args = pjp.getArgs();
        Annotation[][] paramAnnoAry = method.getParameterAnnotations();
        for (Annotation[] item : paramAnnoAry) {
            int paramIndex = ArrayUtils.indexOf(paramAnnoAry, item);
            for (Annotation anno : item) {
                if (anno instanceof LimitKey) {
                    Object arg = args[paramIndex];
                    if (arg instanceof String && StringUtils.isNotBlank((String) arg)) {
                        key = (String) arg;
                        break;
                    }
                }
            }
        }
        if (StringUtils.isBlank(key)) {
            throw new RuntimeException("limitInterceptor - key值不能为空");
        }
        String prefix = limitAnnotation.prefix();
        String[] keyAry = StringUtils.isBlank(prefix) ? new String[]{"limit", key} : new String[]{"limit", prefix, key};
        ImmutableList<String> keys = ImmutableList.of(StringUtils.join(keyAry, "-"));
        try {
            String luaScript = buildLuaScript();
            RedisScript<Number> redisScript = new DefaultRedisScript<Number>(luaScript, Number.class);
            Number count = limitRedisTemplate.execute(redisScript, keys, limitCount, limitPeriod);
            if (count != null && count.intValue() <= limitCount) {
                return pjp.proceed();
            } else {
                String classPath = method.getDeclaringClass().getName() + "." + method.getName();
                throw new RuntimeException("limitInterceptor - 限流被触发："
                        + "class:" + classPath
                        + ", keys:" + keys
                        + ", limitcount:" + limitCount
                        + ", limitPeriod:" + limitPeriod + "s");
            }
        } catch (Throwable e) {
            if (e instanceof RuntimeException) {
                throw new RuntimeException(e.getLocalizedMessage());
            }
            throw new RuntimeException("limitInterceptor - 限流服务异常");
        }
    }
    /**
     * lua 脚本，为了保证执行 redis 命令的原子性
     */
    public String buildLuaScript() {
        StringBuilder lua = new StringBuilder();
        lua.append("local c");
        lua.append("\nc = redis.call('get',KEYS[1])");
        // 调用不超过最大值，则直接返回
        lua.append("\nif c and tonumber(c) > tonumber(ARGV[1]) then");
        lua.append("\nreturn c;");
        lua.append("\nend");
        // 执行计算器自加
        lua.append("\nc = redis.call('incr',KEYS[1])");
        lua.append("\nif tonumber(c) == 1 then");
        // 从第一次调用开始限流，设置对应键值的过期
        lua.append("\nredis.call('expire',KEYS[1],ARGV[2])");
        lua.append("\nend");
        lua.append("\nreturn c;");
        return lua.toString();
    }
    public String getIpAddress() {
        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return ip;
    }
}

TestService

使用方式示例

    @Limit(period = 10, count = 10)
    public String delUserByUrlTest(@LimitKey String token, String thirdId, String url) throws IOException {
        return "success";
    }

到此这篇关于使用AOP+redis+lua做方法限流的实现的文章就介绍到这了,更多相关AOP+redis+lua限流内容请搜索软件开发网以前的文章或继续浏览下面的相关文章希望大家以后多多支持软件开发网！

Lua 方法 aop Redis

1024 个赞