在复杂的分布式系统中,可能有几十个服务相互依赖,这些服务由于某些原因,例如机房的不可靠性、网络服务商的不可靠性等,导致某个服务不可用 。 如果系统不隔离该不可用的服务,可能会导致整个系统不可用。Hystrix 提供了熔断器功能,能够阻止分布式系统中出现联动故障。Hystrix 是通过隔离服务的访问点阻止联动故障的,并提供了故障的解决方案,从而提高了整个分布式系统的弹性。
使用 Hystrix
在 Ribbon 使用 Hystrix
添加依赖包
<dependency>
<groupId>com.netflix.hystrix</groupId>
<artifactId>hystrix-javanica</artifactId>
</dependency>
修改启动类
@EnableHystrix // 启用 Hystrix 熔断器
@EnableEurekaClient
@SpringBootApplication
public class EurekaRibbonClientApp {
public static void main(String[] args){
SpringApplication.run(EurekaRibbonClientApp.class, args);
}
}
修改 Service
@Service
public class RibbonService {
@Autowired
RestTemplate restTemplate;
@HystrixCommand(fallbackMethod = "hiError") // 启用 Hystrix 熔断器
public String hi(String name){
return restTemplate.getForObject("http://eureka-client/hi?name=" + name, String.class);
}
public String hiError(String name){
return "error! sorry, " + name;
}
}
测试
- 启动 eureka-server
- 启动 eureka-ribbon-client
访问 http://localhost:8021/hi?name=victor 可以看到返回的是 hiError 方法执行的结果
在 Feign 使用 Hystrix
application.yml 添加
feign:
hystrix:
enabled: true
添加熔断处理类
@Component
public class HiHystrix implements EurekaClientFeign {
@Override
public String sayHi(String name) {
return "error! sorry, " + name;
}
}
修改 FeignClient
@FeignClient(value = "eureka-client", configuration = FeignConfig.class
, fallback = HiHystrix.class)
public interface EurekaClientFeign {
@GetMapping("/hi")
String sayHi(@RequestParam(value = "name") String name);
}
测试
- 启动 eureka-server
- 启动 eureka-feign-client
访问 http://localhost:8031/hi?name=victor 可以看到返回的是 hiError 方法执行的结果
使用 Hystrix Dashboard 监控熔断器状态
在 Ribbon 使用 Hystrix Dashboard
添加依赖包
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
</dependency>
修改启动类
@EnableHystrix // 启用 Hystrix 熔断器
@EnableHystrixDashboard // 启用 Hystrix Dashboard
@EnableEurekaClient
@SpringBootApplication
public class EurekaRibbonClientApp {
public static void main(String[] args){
SpringApplication.run(EurekaRibbonClientApp.class, args);
}
}
application.yml 添加
management:
endpoints:
web:
exposure:
include: "*"
测试
- 启动 eureka-server
- 启动 eureka-ribbon-client
先访问 http://localhost:8021/hi?name=victor,然后访问 http://localhost:8021/actuator/hystrix.stream 浏览器上会显示熔断器的数据指标
访问 http://localhost:8021/hystrix,然后在界面输入 http://localhost:8021/actuator/hystrix.stream 点击 [Monitor Stream] 按钮可以看到熔断器的各种数据指标
在 Feign 使用 Hystrix Dashboard
添加依赖包
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
</dependency>
与 Ribbon 相比需要添加 spring-cloud-starter-netflix-hystrix 依赖
修改启动类
@EnableFeignClients // 开启 Feign Client
@EnableHystrixDashboard // 启用 Hystrix Dashboard
@EnableCircuitBreaker // 启用 Hystrix 熔断器
@EnableEurekaClient
@SpringBootApplication
public class EurekaFeignClientApp {
public static void main(String[] args){
SpringApplication.run(EurekaFeignClientApp.class, args);
}
}
与 Ribbon 相比需要添加 @EnableCircuitBreaker 注解
application.yml 添加
management:
endpoints:
web:
exposure:
include: "*"
测试
- 启动 eureka-server
- 启动 eureka-feign-client
先访问 http://localhost:8031/hi?name=victor,然后访问 http://localhost:8031/actuator/hystrix.stream 浏览器上会显示熔断器的数据指标
访问 http://localhost:8031/hystrix,然后在界面输入 http://localhost:8031/actuator/hystrix.stream 点击 [Monitor Stream] 按钮可以看到熔断器的各种数据指标
使用 Turbine 聚合监控
新建 spring-cloud-eureka-turbine-client Module
pom
<parent>
<artifactId>spring-cloud-parent</artifactId>
<groupId>com.karonda</groupId>
<version>1.0.0</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>spring-cloud-eureka-turbine-client</artifactId>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-turbine</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
application.yml
server:
port: 8041
eureka:
client:
service-url:
defaultZone: http://localhost:8001/eureka/
spring:
application:
name: turbine-client
turbine:
aggregator:
cluster-config: default
app-config: ribbon-client, feign-client
cluster-name-expression: new String("default")
启动类
@SpringBootApplication
@EnableHystrixDashboard // 启用 Hystrix Dashboard
@EnableTurbine // 启用 Hystrix Turbine
public class EurekaTurbineClientApp {
public static void main(String[] args){
SpringApplication.run(EurekaTurbineClientApp.class, args);
}
}
测试
- 启动 eureka-server
- 启动 eureka-ribbon-client
- 启动 eureka-feign-client
- 启动 eureka-turbine-client
- 访问 http://localhost:8021/hi?name=victor
- 访问 http://localhost:8031/hi?name=victor
访问 http://localhost:8021/hystrix 或 http://localhost:8031/hystrix 然后在界面输入 http://localhost:8041/turbine.stream 点击 [Monitor Stream] 按钮可以看到 eureka-ribbon-client 和 eureka-feign-client 熔断器的各种数据指标
完整代码:GitHub
本人 C# 转 Java 的 newbie, 如有错误或不足欢迎指正,谢谢
?
原文地址:https://www.cnblogs.com/victorbu/p/11015841.html