基於Redis+Lua指令碼實現分散式限流元件封裝的方法
阿新 • • 發佈:2020-11-06
建立限流元件專案
pom.xml檔案中引入相關依賴
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-aop</artifactId> </dependency> <dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>18.0</version> </dependency> </dependencies>
在resources目錄下建立lua指令碼ratelimiter.lua
-- -- Created by IntelliJ IDEA. -- User: 寒夜 -- -- 獲取方法簽名特徵 local methodKey = KEYS[1] redis.log(redis.LOG_DEBUG,'key is',methodKey) -- 呼叫指令碼傳入的限流大小 local limit = tonumber(ARGV[1]) -- 獲取當前流量大小 local count = tonumber(redis.call('get',methodKey) or "0") -- 是否超出限流閾值 if count + 1 > limit then -- 拒絕服務訪問 return false else -- 沒有超過閾值 -- 設定當前訪問的數量+1 redis.call("INCRBY",methodKey,1) -- 設定過期時間 redis.call("EXPIRE",1) -- 放行 return true end
建立RedisConfiguration 類
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<String,String> 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; } }
建立一個自定義註解
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 ""; }
建立一個切入點
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<Boolean> rateLimitLua; public AccessLimiterAspect(StringRedisTemplate stringRedisTemplate,RedisScript<Boolean> 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. 獲得方法簽名,作為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(); // 如果沒設定methodkey,從呼叫方法簽名生成自動一個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. 呼叫Redis boolean acquired = stringRedisTemplate.execute( rateLimitLua,// Lua script的真身 Lists.newArrayList(key),// Lua指令碼中的Key列表 Integer.toString(limit) // Lua指令碼Value列表 ); if (!acquired) { log.error("your access is blocked,key={}",key); throw new RuntimeException("Your access is blocked"); } } }
建立測試專案
pom.xml中引入元件
application.yml配置
spring: redis: host: 192.168.0.218 port: 6379 password: 123456 database: 0 application: name: ratelimiter-test server: port: 10087
建立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! 注意配置掃包路徑(com.hy路徑不同) @GetMapping("test-annotation") @AccessLimiter(limit = 1) public String testAnnotation() { return "success"; } }
開始測試,快速點選結果如下
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