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使用AOP+redis+lua做方法限流的實現(xiàn)_Redis

作者：竹子竹枝 ? 更新時間： 2022-06-27 編程語言

需求

公司里使用OneByOne的方式刪除數(shù)據(jù)，為了防止一段時間內(nèi)刪除數(shù)據(jù)過多，讓我這邊做一個接口限流，超過一定閾值后報異常，終止刪除操作。

實現(xiàn)方式

創(chuàng)建自定義注解 @limit 讓使用者在需要的地方配置 count(一定時間內(nèi)最多訪問次數(shù))、 period(給定的時間范圍)，也就是訪問頻率。然后通過LimitInterceptor攔截方法的請求， 通過 redis+lua 腳本的方式，控制訪問頻率。

源碼

Limit 注解

用于配置方法的訪問頻率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的前綴
     */
    String prefix() default "";
    /**
     * 一定時間內(nèi)最多訪問次數(shù)
     */
    @Min(1)
    int count();
    /**
     * 給定的時間范圍 單位(秒)
     */
    @Min(1)
    int period();
    /**
     * 限流的類型(用戶自定義key或者請求ip)
     */
    LimitType limitType() default LimitType.CUSTOMER;
}

LimitKey

用于標(biāo)記參數(shù)，作為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

枚舉，redis key值的類型，支持自定義key和ip、methodName中獲取key

public enum LimitType {
    /**
     * 自定義key
     */
    CUSTOMER,
    /**
     * 請求者IP
     */
    IP,
    /**
     * 方法名稱
     */
    METHOD_NAME;
}

RedisLimiterHelper

初始化一個限流用到的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 的方式來攔截請求，控制訪問頻率

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();
        /**
         * 根據(jù)限流類型獲取不同的key ,如果不傳我們會以方法名作為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 - 無效的枚舉值");
        }
        /**
         * 獲取注解標(biāo)注的 key，這個是優(yōu)先級最高的，會覆蓋前面的 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值不能為空");
        }
        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 - 限流被觸發(fā)："
                        + "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 - 限流服務(wù)異常");
        }
    }
    /**
     * lua 腳本，為了保證執(zhí)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])");
        // 調(diào)用不超過最大值，則直接返回
        lua.append("\nif c and tonumber(c) > tonumber(ARGV[1]) then");
        lua.append("\nreturn c;");
        lua.append("\nend");
        // 執(zhí)行計算器自加
        lua.append("\nc = redis.call('incr',KEYS[1])");
        lua.append("\nif tonumber(c) == 1 then");
        // 從第一次調(diào)用開始限流，設(shè)置對應(yīng)鍵值的過期
        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";
    }

原文鏈接：https://juejin.cn/post/7091220805853872158

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