Version: Next

Sentinel 服务熔断

Sentinel 整合 Ribbon、OpenFeign

环境准备

准备——新建一些模块
两个服务提供者 provider-payment9003、9004
一个服务消费者 consumer-order84
84 通过 Nacos 找到 9003、9004 的真实地址，通过 Ribbon 负载均衡的进行访问

Cloudalibaba-provider-payment9003

POM
YAML
主启动
业务类

<dependencies>
 <!-- SpringCloud ailibaba nacos-->
 <dependency>
     <groupId>com.alibaba.cloud</groupId>
     <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
 </dependency>
 <!-- SpringCloud ailibaba sentinel-->
 <dependency>
     <groupId>com.alibaba.cloud</groupId>
     <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
 </dependency>
 <dependency><!-- 引用自己定义的api通用包，可以使用Payment支付Entity -->
     <groupId>org.example</groupId>
     <artifactId>cloud-api-commons</artifactId>
     <version>1.0-SNAPSHOT</version>
 </dependency>
 <dependency>
     <groupId>org.springframework.cloud</groupId>
     <artifactId>spring-cloud-starter-openfeign</artifactId>
 </dependency>
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <!--监控-->
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-actuator</artifactId>
 </dependency>
 <!--热部署-->
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-devtools</artifactId>
     <scope>runtime</scope>
     <optional>true</optional>
 </dependency>
 <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
     <optional>true</optional>
 </dependency>
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-test</artifactId>
     <scope>test</scope>
 </dependency>
</dependencies>

Cloudalibaba-provider-payment9004

照着 9003 弄一个，改一下端口号

Cloudalibaba-consumer-nacos-order84

POM
YAML
主启动
业务类

<dependencies>
 <!-- SpringCloud ailibaba nacos-->
 <dependency>
     <groupId>com.alibaba.cloud</groupId>
     <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
 </dependency>
 <!-- SpringCloud ailibaba sentinel-->
 <dependency>
     <groupId>com.alibaba.cloud</groupId>
     <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
 </dependency>
 <dependency><!-- 引用自己定义的api通用包，可以使用Payment支付Entity -->
     <groupId>org.example</groupId>
     <artifactId>cloud-api-commons</artifactId>
     <version>1.0-SNAPSHOT</version>
 </dependency>
 <dependency>
     <groupId>org.springframework.cloud</groupId>
     <artifactId>spring-cloud-starter-openfeign</artifactId>
 </dependency>
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <!--监控-->
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-actuator</artifactId>
 </dependency>
 <!--热部署-->
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-devtools</artifactId>
     <scope>runtime</scope>
     <optional>true</optional>
 </dependency>
 <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
     <optional>true</optional>
 </dependency>
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-test</artifactId>
     <scope>test</scope>
 </dependency>
</dependencies>

服务熔断无配置

重启 9003、9004
启动 84
访问 http://localhost:84/consumer/fallback/1，得到正常响应，且可以看到 9003、9004 两个节点在轮询负载均衡

再看 order84 Controller 中的业务代码
- 当 id 为 1、2、3 时，能到 9003、9004 查到数据正常返回
- 当为 4 抛出一个 非法参数异常
- 如果是 1、2、3、4 以外的数字，会跑去 9003、9004 查，然后啥也查不到，得到的响应中 data 为空，于是 84 自己抛出一个 空指针异常
- 上述两个异常都是 Java 层面的，后续就是演示用 fallback 属性来处理它们

@RequestMapping("/consumer/fallback/{id}")
@SentinelResource(value = "fallback")
// @SentinelResource(value = "fallback",fallback ="handlerFallback")
// 异常忽略 exceptionsToTrace = IllegalArgumentException.class 忽略指定的异常
// @SentinelResource(value = "fallback", fallback = "handlerFallback", blockHandler = "blockHandler")
public CommonResult<Payment> fallback(@PathVariable Long id) {
  CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/" + id, CommonResult.class, id);

    if (id == 4) {
      throw new IllegalArgumentException("IllegalArgument ,非法参数异常...");
    } else if (result.getData() == null) {
      throw new NullPointerException("NullPointerException,该ID没有对应记录，空指针异常");
    }

    return result;
}

服务熔断只配置 fallback

@SentinelResource 加上 fallback 属性
fallback 属性指定一个兜底方法
@RequestMapping("/consumer/fallback/{id}")
// @SentinelResource(value = "fallback")
@SentinelResource(value = "fallback", fallback = "handlerFallback")
// 异常忽略 exceptionsToTrace = IllegalArgumentException.class 忽略指定的异常
// @SentinelResource(value = "fallback", fallback = "handlerFallback", blockHandler = "blockHandler")
public CommonResult<Payment> fallback(@PathVariable Long id) {
CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/" + id, CommonResult.class, id);

if (id == 4) {
throw new IllegalArgumentException("IllegalArgument ,非法参数异常...");
} else if (result.getData() == null) {
throw new NullPointerException("NullPointerException,该ID没有对应记录，空指针异常");
}

return result;
}

// 兜底方法
public CommonResult handlerFallback(@PathVariable Long id, Throwable e) {
Payment payment = new Payment(id, "null");
return new CommonResult(444, "异常handlerFallback，exception内容： " + e.getMessage(), payment);
}
访问 http://localhost:84/consumer/fallback/4，触发了兜底方法，打印了自定义异常信息，屏蔽了 500 错误及异常信息栈
访问 http://localhost:84/consumer/fallback/5，触发了兜底方法，打印了自定义异常信息，屏蔽了 500 错误及异常信息栈
id 4 兜底响应
id 5 兜底响应
{
"code": 444,
"message": "异常handlerFallback，exception内容： IllegalArgument ,非法参数异常...",
"data": {
"id": 4,
"serial": "null"
}
}

服务熔断只配置 blockHandler

@RequestMapping("/consumer/fallback/{id}")
//    @SentinelResource(value = "fallback")
//    @SentinelResource(value = "fallback", fallback = "handlerFallback")
// 异常忽略 exceptionsToTrace = IllegalArgumentException.class 忽略指定的异常
@SentinelResource(value = "fallback", blockHandler = "blockHandler")
// @SentinelResource(value = "fallback", fallback = "handlerFallback", blockHandler = "blockHandler")
public CommonResult<Payment> fallback(@PathVariable Long id) {
  CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/" + id, CommonResult.class, id);

    if (id == 4) {
        throw new IllegalArgumentException("IllegalArgument ,非法参数异常...");
    } else if (result.getData() == null) {
        throw new NullPointerException("NullPointerException,该ID没有对应记录，空指针异常");
    }
  
    return result;
}

public CommonResult blockHandler(@PathVariable Long id, BlockException e) {
    Payment payment = new Payment(id, "null");
    return new CommonResult(444, "blockHandler-sentinel 限流，BlockException： " + e.getMessage(), payment);
}

添加 Sentinel 配置
给资源名 fallback 添加降级规则

测试
访问 http://localhost:84/consumer/fallback/4
Java 异常会直接以 500 报文响应
疯狂访问，触发降级，得到 blockHandler 方法执行后的响应结果

服务熔断两个都配

@RequestMapping("/consumer/fallback/{id}")
//    @SentinelResource(value = "fallback")
//    @SentinelResource(value = "fallback", fallback = "handlerFallback")
// 异常忽略 exceptionsToTrace = IllegalArgumentException.class 忽略指定的异常
//    @SentinelResource(value = "fallback", blockHandler = "blockHandler")
@SentinelResource(value = "fallback", fallback = "handlerFallback", blockHandler = "blockHandler")
public CommonResult<Payment> fallback(@PathVariable Long id) {
    CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/" + id, CommonResult.class, id);

    if (id == 4) {
        throw new IllegalArgumentException("IllegalArgument ,非法参数异常...");
    } else if (result.getData() == null) {
        throw new NullPointerException("NullPointerException,该ID没有对应记录，空指针异常");
    }

    return result;
}


public CommonResult handlerFallback(@PathVariable Long id, Throwable e) {
    Payment payment = new Payment(id, "null");
    return new CommonResult(444, "异常handlerFallback，exception内容： " + e.getMessage(), payment);
}


public CommonResult blockHandler(@PathVariable Long id, BlockException e) {
    Payment payment = new Payment(id, "null");
    return new CommonResult(444, "blockHandler-sentinel 限流，BlockException： " + e.getMessage(), payment);
}

Java 的错误会触发 fallback
违反 Sentinel 设置会触发 blockHandler
如果一个请求把两个都触发了会发生什么？
执行的是 blockHandler，因为 Sentinel 的限流直接阻止了方法的执行，根本执行不到 fallback

异常忽略

使用：exceptionsToTrace 属性指定要忽略的异常类型

exceptionsToTrace = IllegalArgumentException.class 忽略指定的异常

@RequestMapping("/consumer/fallback/{id}")
//    @SentinelResource(value = "fallback")
//    @SentinelResource(value = "fallback", fallback = "handlerFallback")
// 异常忽略 exceptionsToTrace = IllegalArgumentException.class 忽略指定的异常
//    @SentinelResource(value = "fallback", blockHandler = "blockHandler")
//    @SentinelResource(value = "fallback", fallback = "handlerFallback", blockHandler = "blockHandler")
@SentinelResource(value = "fallback", fallback = "handlerFallback", blockHandler = "blockHandler",exceptionsToIgnore = IllegalArgumentException.class)
public CommonResult<Payment> fallback(@PathVariable Long id) {
    CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/" + id, CommonResult.class, id);

    if (id == 4) {
        throw new IllegalArgumentException("IllegalArgument ,非法参数异常...");
    } else if (result.getData() == null) {
        throw new NullPointerException("NullPointerException,该ID没有对应记录，空指针异常");
    }

    return result;
}


public CommonResult handlerFallback(@PathVariable Long id, Throwable e) {
    Payment payment = new Payment(id, "null");
    return new CommonResult(444, "异常handlerFallback，exception内容： " + e.getMessage(), payment);
}


public CommonResult blockHandler(@PathVariable Long id, BlockException e) {
    Payment payment = new Payment(id, "null");
    return new CommonResult(444, "blockHandler-sentinel 限流，BlockException： " + e.getMessage(), payment);
}

整合 OpenFeign

修改 order84

POM
YAML
主启动
业务类

引入 OpenFeign ，之前引入过了

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

测试
只启动 9003
重启 84
访问 http://localhost:84/consumer/paymentSQL/1，可以得到正常响应，来自 9003
测试服务降级
把 9003 关了，继续访问，当调用到 9003 时，因为 9003 挂了，OpenFeign 的调用就会出问题
应当触发定义的自定义兜底类
{
"code": 444,
"message": "服务降级返回，---PaymentFallbackService",
"data": {
"id": 1,
"serial": "ErrorSerial"
}
}

Sentinel 服务熔断#

环境准备#

Cloudalibaba-provider-payment9003#

Cloudalibaba-provider-payment9004#

Cloudalibaba-consumer-nacos-order84#

服务熔断无配置#

服务熔断只配置 fallback#

服务熔断只配置 blockHandler#

添加 Sentinel 配置#

测试#

服务熔断两个都配#

如果一个请求把两个都触发了会发生什么？#

异常忽略#

整合 OpenFeign#

测试#

测试服务降级#

Sentinel 服务熔断

环境准备

Cloudalibaba-provider-payment9003

Cloudalibaba-provider-payment9004

Cloudalibaba-consumer-nacos-order84

服务熔断无配置

服务熔断只配置 fallback

服务熔断只配置 blockHandler

添加 Sentinel 配置

测试

服务熔断两个都配

如果一个请求把两个都触发了会发生什么？

异常忽略

整合 OpenFeign

测试

测试服务降级