Redis+Lua限流元件封裝
阿新 • • 發佈:2021-01-16
1.熟悉下lua語法
2.lua安裝,IDEA安裝lua外掛
安裝Lua: 1. 參考http://www.lua.org/ftp/教程,下載5.3.5_1版本,本地安裝 如果是Mac,那用brew工具直接執行brew install lua就可以順利安裝, 有關brew工具的安裝可以參考https://brew.sh/網站,建議翻牆否則會很慢。 使用brew安裝後的目錄在/usr/local/Cellar/lua/5.3.5_1 2. 安裝IDEA外掛,在IDEA->Preferences面板,Plugins, 裡面Browse repositories,在裡面搜尋lua,然後就選擇同名外掛lua。安裝好後重啟IDEA 3. 配置Lua SDK的位置: IDEA->File->Project Structure, 選擇新增Lua,路徑指向Lua SDK的bin資料夾,我本地的地址是: /usr/local/Cellar/lua/5.3.5_1/bin
3.建立jar模組,作為公用元件
具體的檔案及程式碼內容如下:
1.pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent> <artifactId>xxx</artifactId> <groupId>com.xxx</groupId> <version>1.0.0-SNAPSHOT</version> <relativePath>../../pom.xml</relativePath> </parent> <modelVersion>4.0.0</modelVersion> <packaging>jar</packaging> <artifactId>ratelimiter-annotation</artifactId> <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> </project>
2.resource目錄下新增lua指令碼
ratelimiter.lua
-- 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:秒 redis.call("EXPIRE", methodKey, 1) -- 放行 return true end
3.src目錄包結構自己定義,新增配置類
RedisConfiguration.java
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;
@Configuration
public class RedisConfiguration {
// 如果本地也配置了StringRedisTemplate,可能會產生衝突
// 可以指定@Primary,或者指定載入特定的@Qualifier
@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;
}
}
4.定義註解截切面類與具體通過redis呼叫lua指令碼實現限流的兩個類。放到建立的一個annotation包下
AccessLimiter.java
import java.lang.annotation.*;
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface AccessLimiter {
int limit();
String methodKey() default "";
}
AccessLimiterAspect.java
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.beans.factory.annotation.Autowired;
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;
@Slf4j
@Aspect
@Component
public class AccessLimiterAspect {
@Autowired
private StringRedisTemplate stringRedisTemplate;
@Autowired
private RedisScript<Boolean> rateLimitLua;
@Pointcut("@annotation(com.xxx.xxx.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();
Integer 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
limit.toString() // Lua指令碼Value列表
);
if (!acquired) {
log.error("your access is blocked, key={}", key);
throw new RuntimeException("Your access is blocked");
}
}
}
至此redis+lua限流元件開發完成。下面在其他模組中使用測試。
使用步驟:
1.在需要用到的工程中引入限流元件的依賴包
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>ratelimiter-annotation</artifactId>
<version>${project.version}</version>
</dependency>
2.在需要限流的controller介面上進行限流注解即可。
// limit後的值為限流流量數限1秒1個請求
@GetMapping("test-annotation")
@com.xxx.xxx.annotation.AccessLimiter(limit = 1)
public String testAnnotation() {
return "success";
}