Circuit Breaker解决方案Spring Cloud Hystrix组件。
以 2.2.0.release 为例,教你如何入门该组件。
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-hystrix</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>
本例采用Maven进行project的build等工作。下面关于spring cloud的discover和config模块配置什么的被剔除了,为了减少篇幅内容,但实际的spring cloud方案中是一定有的。
这个项目就是用来展示监控统计Circuit Breaker的数据,也就是hystrix.stream报上来的各应用线程接口熔断统计数据。在微服务体系中,dashboard要独立搭建项目,因为后续可能需要增加定制功能。dashboard需要支持单节点的统计数据同时,还需要能支持集群统计数据,因为微服务里每个应用至少是部署2台的,这些熔断数据不可能一个一个节点单独查看,需要汇总在一起,这里就用到了turbine组件。
pom.xml:
<dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-hystrix</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>
bootstrap.yml
spring: application: name: service-hystrix-dashbaord profiles: active: ${ENV:local} server: port: 8888 turbine: app-config: service-demo3 cluster-name-expression: "'default'"
applicatin.java
@SpringBootApplication @EnableHystrixDashboard @EnableTurbine public class HystrixApp { public static void main( String[] args ) { SpringApplication.run(HystrixApp.class,args); } }
demo3是一个应用系统实际集成使用的样例。应用系统中只需要引入hystrix组件即可,但是对于springboot项目还需要引入actuator组件。另外openfeign组件的引入是为提供另一种使用hystrix方式的样例,应用系统中 有两种方式 使用hystrix组件。
pom.xml:
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-hystrix</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency>
bootstrap.yml
spring: application: name: service-demo3 profiles: active: ${ENV:local} management: endpoints: web: exposure: include: hystrix.stream
application.java
@SpringBootApplication @EnableEurekaClient @EnableCircuitBreaker @EnableFeignClients public class Demo3App { public static void main( String[] args ) { SpringApplication.run(Demo3App.class,args); } }
hystrix.stream
@Bean public ServletRegistrationBean getServlet(){ HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet(); ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet); registrationBean.setLoadOnStartup(1); registrationBean.addUrlMappings("/actuator/hystrix.stream"); registrationBean.setName("HystrixMetricsStreamServlet"); return registrationBean; }
这个是hystrix2.0一个小BUG,需要添加@Bean把监控统计数据的接口暴露成 /actuator/hystrix.stream
接口路径方式。
@RestController public class UserController { @Autowired(required = false) ITestService iTestService; @Autowired(required = false) IUserService iUserService; @GetMapping("/user/users") public String getUsers(){ return "users is success" + iUserService.getUserId("13567890123"); } @HystrixCommand(fallbackMethod = "defaultFindUser") @GetMapping("/user/find") public String getFindUser(){ return iTestService.sayHello("test"); } public String defaultFindUser(){ return "hystrix default data"; } }
OpenFeign作为一个前端路由的HTTP Client工具,自身已经集成了hystrix功能。
@FeignClient(value = "service-demo2",fallback = UserServiceFallbackImpl.class) public interface IUserService { @RequestMapping(value="/user/{mobile}", method= RequestMethod.GET) @ResponseBody Long getUserId(@PathVariable(name = "mobile") String mobile); } @Service public class UserServiceFallbackImpl implements IUserService { @Override public Long getUserId(String mobile) { System.out.println(mobile); return 0L; } }
样例代码: https://github.com/owen-jia/cloud-parent