Ribbon负载均衡及Feign消费者调用服务
微服务调用Ribbon
简介
前面讲了eureka服务注册与发现,但是结合eureka集群的服务调用没讲。
这里的话 就要用到Ribbon,结合eureka,来实现服务的调用;
Ribbon是Netflix发布的负载均衡器,它有助于控制HTTP和TCP的客户端的行为。为Ribbon配置服务提供者地址后,Ribbon就可基于某种负载均衡算法,自动地帮助服务消费者去请求。Ribbon默认为我们提供了很多负载均衡算法,例如轮询、随机等。当然,我们也可为Ribbon实现自定义的负载均衡算法。
在Spring Cloud中,当Ribbon与Eureka配合使用时,Ribbon可自动从Eureka Server获取服务提供者地址列表,并基于负载均衡算法,请求其中一个服务提供者实例。展示了Ribbon与Eureka配合使用时的架构。
初步应用
Ribbon是客户端负载均衡,所以肯定集成再消费端,也就是consumer端
我们修改microservice-student-consumer-80
首先,引入依赖,pom.xml 加入 ribbon相关依赖
<!--ribbon相关依赖--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-ribbon</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> </dependency>
application.yml
server: port: 8080 context-path: / eureka: client: service-url: defaultZone: http://eureka2001.huang.com:2001/eureka/,http://eureka2002.huang.com:2002/eureka/,http://eureka2003.huang.com:2003/eureka/ register-with-eureka: false
ribbon结合eureka来调用服务提供者;
SpringCloudConfig也改成 要加个负载均衡配置 @LoadBalanced
package com.huang.microservicestudentconsumer80.config; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.client.RestTemplate; @Configuration public class SpringCloudConfig { @LoadBalanced @Bean public RestTemplate getRestTemplate(){ return new RestTemplate(); } }
因为和eureka整合,所以启动类StudentConsumerApplication_80 加个注解 @EnableEurekaClient
这里还有一个,要修改下StudentConsumerController的PRE_HOST,改成指定的微服务应用名称;
当然这里要先在服务提供者microservice-student-provider-1001的application.yml加下配置,指定下应用名称:
application:
name: microservice-student
我们的微服务应用名称是 microservice-student
所以服务调用者这边的控制器里PRE_HOST改成 http://MICROSERVICE-STUDENT即可;
MICROSERVICE-STUDENT为Eureka注册中心的应用名称
@RestController @RequestMapping("/student") public class StudentConsumerController { // private final static String SERVER_IP_PORT = "http://localhost:1001"; private final static String SERVER_IP_PORT = "http://MICROSERVICE-STUDENT";
上面配置好后,我们可以测试下;
先启动三个eureka,然后再启动服务提供者,再启动服务消费者;
结果就出来了,说明配置OK;
Ribbon负载均衡
按照它microservice-student-provider-1001建立一个microservice-student-provider子项目,然后将microservice-student-provider-1001这个子项目干掉;
前面搭建了初步例子,但是还没实现真正负载均衡,我们这里要先搞三个服务提供者集群,然后才能演示负载均衡,以及负载均衡策略;
新建项目microservice-student-provider-1002,microservice-student-provider-1003
pom.xml,application.yml,以及java类都复制一份,启动类名称对应的改下;
yml配置文件有两处要对应的改下,port端口改下,以及服务实例名称改下;
相关代码如下
相关pom
<properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>com.huang</groupId> <artifactId>microservice-common</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <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-data-jpa</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> </dependency> <!-- 修改后立即生效,热部署 --> <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> <dependency> <groupId>com.huang</groupId> <artifactId>microservice-common</artifactId> <version>1.0-SNAPSHOT</version> <scope>compile</scope> </dependency> <!--添加注册中心Eureka相关配置--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> </dependency> <!-- actuator监控引入 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies>
Yml文件
--- server: port: 1001 context-path: / spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/huang?useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1001 eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1001 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.huang.com:2001/eureka/,http://eureka2002.huang.com:2002/eureka/,http://eureka2003.huang.com:2003/eureka/ info: groupId: com.huang.testSpringcloud artifactId: microservice-student-provider-1001 version: 1.0-SNAPSHOT userName: http://huang.com phone: 123456 --- server: port: 1002 context-path: / spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/huang?useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1002 eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1002 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.huang.com:2001/eureka/,http://eureka2002.huang.com:2002/eureka/,http://eureka2003.huang.com:2003/eureka/ info: groupId: com.huang.testSpringcloud artifactId: microservice-student-provider-1002 version: 1.0-SNAPSHOT userName: http://huang.com phone: 123456 --- server: port: 1003 context-path: / spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/huang?useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1003 eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1003 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.huang.com:2001/eureka/,http://eureka2002.huang.com:2002/eureka/,http://eureka2003.huang.com:2003/eureka/ info: groupId: com.huang.testSpringcloud artifactId: microservice-student-provider-1003 version: 1.0-SNAPSHOT userName: http://huang.com phone: 123456
启动类
package com.huang.microservicestudentprovider; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.autoconfigure.domain.EntityScan; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; @EntityScan("com.huang.*.*") @EnableEurekaClient @SpringBootApplication public class MicroserviceStudentProviderApplication { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentProviderApplication.class, args); } }
StudentProviderController.java
@Value("${server.port}") private String port; @RequestMapping("/ribbon") public String ribbon(){ return "工号【"+port+"】正在为您服务"; }
StudentConsumerController.java
@RequestMapping("/ribbon") public String ribbon(){ return restTemplate.getForObject(SERVER_IP_PORT + "/student/ribbon", String.class); }
先测试服务提供者:
http://localhost:1001/student/list
http://localhost:1002/student/list
http://localhost:1003/student/list
看看是否有结果;
再测试下 eureka:
http://eureka2001.javaxl.com:2001/
http://eureka2002.javaxl.com:2002/
http://eureka2003.javaxl.com:2003/
有这种的话,就说明没问题;
然后再启动服务消费者:
http://localhost/student/list 多刷新几次 看控制台,我们看到 有默认的轮询策略,访问对应的服务提供者;
但是这种默认的轮询策略肯定是不能满足实际需求的,比如有3个服务提供者,突然挂了一个,这样的话,默认轮询 ,总有1/3的概率访问失败; 所以我们看下ribbon默认给我们提供的策略有哪些;
策略名 | 策略声明 | 策略描述 |
BestAvailableRule | public class BestAvailableRule extends ClientConfigEnabledRoundRobinRule | 选择一个最小的并发请求的server |
AvailabilityFilteringRule | public class AvailabilityFilteringRule extends PredicateBasedRule | 过滤掉那些因为一直连接失败的被标记为circuit tripped的后端server,并过滤掉那些高并发的的后端server(active connections 超过配置的阈值) |
WeightedResponseTimeRule | public class WeightedResponseTimeRule extends RoundRobinRule | 根据响应时间分配一个weight,响应时间越长,weight越小,被选中的可能性越低。 |
RetryRule | public class RetryRule extends AbstractLoadBalancerRule | 对选定的负载均衡策略机上重试机制。 |
RoundRobinRule | public class RoundRobinRule extends AbstractLoadBalancerRule | roundRobin方式轮询选择server |
RandomRule | public class RandomRule extends AbstractLoadBalancerRule | 随机选择一个server |
ZoneAvoidanceRule | public class ZoneAvoidanceRule extends PredicateBasedRule | 复合判断server所在区域的性能和server的可用性选择server |
默认7个策略,根据具体产品需求,我们选用;
代码中如何假如呢;
服务消费端 SpringCloudConfig配置类
指定IRule实现;
这里我们演示用 RetryRule,大伙可以自行测试;
package com.huang.microservicestudentconsumer80.config; import com.netflix.loadbalancer.IRule; import com.netflix.loadbalancer.RetryRule; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.client.RestTemplate; @Configuration public class SpringCloudConfig { @LoadBalanced // 引入ribbon负载均衡 @Bean public RestTemplate getRestTemplate() { return new RestTemplate(); } /** * 自定义轮询算法 * @return */ @Bean public IRule myRule(){ return new RetryRule(); } }