How to use AOP+redis+lua for current limiting

Requirements

The company uses the OneByOne method to delete data. In order to prevent too much data from being deleted within a period of time, let me create an interface current limit here. When it exceeds a certain threshold, an exception will be reported and terminated. delete operation.

Implementation method

Create custom annotations@limit Allow users to configure count where needed (maximum access within a certain period of time times), period (given time range), which is the access frequency. Then intercept the method request through LimitInterceptor, and control the access frequency through the redis lua script.

Source code

Limit annotation

Used to configure the access frequency count and period of the method

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

Used to mark parameters as part of the redis key value

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

enumeration, the type of the redis key value, supports customization Get key from key, ip and methodName

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

RedisLimiterHelper

Initialize a redisTemplate Bean used for current limiting

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

Use aop method to intercept requests and control access frequency

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(&#39;get&#39;,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(&#39;incr&#39;,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(&#39;expire&#39;,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

Usage example

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

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