Microservice capability development practice based on Spring Cloud

With the rapid development of cloud computing and big data technology, the architectural design and development methods of enterprise systems are also constantly changing. The microservice architecture is one of the important changes. It is an architectural model that splits a single application into a set of small services. Each service cooperates with each other based on a lightweight communication mechanism, thereby achieving a more Flexible, scalable and maintainable systems.

As one of the most popular microservice frameworks currently, Spring Cloud provides a complete set of microservice development solutions, including microservice discovery, configuration, communication, load balancing, circuit breakers, API gateways, etc. . This article will introduce the microservice capability development practice based on Spring Cloud, as well as some problems and solutions encountered in practice.

1. Basic principles of microservice architecture

Microservice architecture is an architectural pattern that splits a single application into a set of small services. Each service is based on lightweight The communication mechanisms cooperate with each other to achieve a more flexible, scalable and maintainable system. The basic principles of microservice architecture include:

1. Service splitting: Divide a single application into a set of small services according to business areas or functional modules, and each service runs and upgrades independently.

2. Service communication: Services cooperate with each other based on lightweight communication mechanisms. Communication methods include RESTful API, message queue, RPC, etc.

3. Service discovery and registration: Service life cycle management, including service registration to the service registration center, service discovery and load balancing, etc.

4. Data partitioning: Split data into different services through data partitioning to ensure data isolation between services.

5. Automated operation and maintenance: Realize automatic deployment, monitoring and maintenance of services through automated tools, improving the reliability and maintainability of the system.

2. Spring Cloud Microservice Framework

Spring Cloud is a microservice framework based on Spring Boot and provides a complete set of microservice development solutions. Spring Cloud includes the following core components:

1. Service discovery and registration: Eureka, Consul, Zookeeper, etc.

2. Client load balancing: Ribbon.

3. Circuit Breaker: Hystrix.

4. Service gateway: Zuul2.

5. Distributed configuration center: Spring Cloud Config.

6. Message bus: Spring Cloud Bus.

3. Spring Cloud Microservice Development Practice

The following takes a simple microservice application as an example to introduce the microservice development practice based on Spring Cloud.

1. Create an Eureka registration center

First, create an Eureka registration center to realize service discovery and registration through Eureka.

In the Spring Boot project, integrate Eureka by adding the following dependencies:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

Add the @EnableEurekaServer annotation in the startup class:

@EnableEurekaServer
@SpringBootApplication
public class EurekaServerApplication {
   public static void main(String[] args) {
      SpringApplication.run(EurekaServerApplication.class, args);
   }
}

After starting the Eureka registration center, you can Visit http://localhost:8761 in the browser to see the management interface of the registration center.

2. Create a service provider

Create a simple service provider and provide a hello interface to return a string.

In the Spring Boot project, integrate Eureka and Ribbon by adding the following dependencies:

<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

In the service provider, enable the Eureka client by adding the @EnableDiscoveryClient annotation:

@SpringBootApplication
@EnableDiscoveryClient
public class ServiceProviderApplication {
   public static void main(String[] args) {
      SpringApplication.run(ServiceProviderApplication.class, args);
   }
}

Create a RestController to provide hello interface:

@RestController
public class HelloController {
   @RequestMapping("/hello")
   public String hello() {
      return "Hello World!";
   }
}

3. Create a service consumer

Create a service consumer, call the interface provided by the service provider, and achieve load balancing through Ribbon.

In the Spring Boot project, integrate Eureka and Ribbon by adding the following dependencies:

<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

In the service consumer, enable the Eureka client by adding the @EnableDiscoveryClient annotation, and pass the @LoadBalanced annotation To enable Ribbon client load balancing:

@SpringBootApplication
@EnableDiscoveryClient
public class ServiceConsumerApplication {
   public static void main(String[] args) {
      SpringApplication.run(ServiceConsumerApplication.class, args);
   }
 
   @Bean
   @LoadBalanced
   public RestTemplate restTemplate() {
      return new RestTemplate();
   }
}

Create a RestController to call the hello interface of the service provider:

@RestController
public class HelloController {
   @Autowired
   private RestTemplate restTemplate;
 
   @RequestMapping("/hello")
   public String hello() {
      String url = "http://service-provider/hello";
      return restTemplate.getForObject(url, String.class);
   }
}

4. Create a service gateway

Create a service gateway, Expose all microservice interfaces to the outside world, and implement routing, forwarding and filtering through Zuul.

In the Spring Boot project, integrate Eureka and Zuul by adding the following dependencies:

<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
</dependency>

In the service gateway, enable Zuul by adding the @EnableZuulProxy annotation:

@SpringBootApplication
@EnableZuulProxy
public class ApiGatewayApplication {
   public static void main(String[] args) {
      SpringApplication.run(ApiGatewayApplication.class, args);
   }
}

Configure the gateway routing information and add the following configuration in application.yml:

zuul:
  routes:
    service-provider:
      path: /api/**
      serviceId: service-provider

5. Create a configuration center

Create a configuration center and manage the configuration through the Git warehouse to achieve centralized management and configuration of the configuration. Dynamic refresh.

In the Spring Boot project, integrate the Config Server by adding the following dependencies:

<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-config-server</artifactId>
</dependency>

In the configuration center, enable the configuration center by adding the @EnableConfigServer annotation:

@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {
   public static void main(String[] args) {
      SpringApplication.run(ConfigServerApplication.class, args);
   }
}

Configure Git warehouse information and read rules in application.yml:

spring:
  cloud:
    config:
      server:
        git:
          uri: git://http://gitlab.example.com/abc/config-repo.git
          search-paths: '{application}'
  profiles:
    active: native
  paths:
    config.path: /usr/local/config-repo

6. Implement the circuit breaker of the service

Create a circuit breaker to handle the degradation of the service when exceptions or failures occur operate.

In the Spring Boot project, integrate Hystrix by adding the following dependencies:

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

In the service provider, implement the circuit breaker by adding the @HystrixCommand annotation:

@RestController
public class HelloController {
   @RequestMapping("/hello")
   @HystrixCommand(fallbackMethod = "fallback")
   public String hello() {
      ...
   }
 
   public String fallback() {
      return "Fallback";
   }
}

7. Implement service monitoring

Create a monitoring center for monitoring and data analysis of the interfaces provided by microservices to achieve real-time monitoring of service status.

In the Spring Boot project, integrate Hystrix Dashboard and Turbine by adding the following dependencies:

<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>

在监控中心中，通过添加@EnableHystrixDashboard注解来启用Hystrix Dashboard：

@SpringBootApplication
@EnableHystrixDashboard
public class MonitorCenterApplication {
   public static void main(String[] args) {
      SpringApplication.run(MonitorCenterApplication.class, args);
   }
}

在turbine服务提供者中，通过添加@EnableTurbine注解来启用Turbine：

@SpringBootApplication
@EnableTurbine
public class TurbineServerApplication {
   public static void main(String[] args) {
      SpringApplication.run(TurbineServerApplication.class, args);
   }
}

在application.yml中配置Turbine的信息：

turbine:
  aggregator:
    clusterConfig: service-consumer
  appConfig: service-consumer,service-provider
  clusterNameExpression: new String("default")

四、总结

Spring Cloud是一套完备的微服务开发解决方案，通过其提供的一系列组件和架构设计原则，开发者可以轻松构建出高可用、高扩展和易维护的微服务应用。在实践中，我们发现Spring Cloud不但提供了完备的技术支持，同时还提供了很好的学习资源和社区支持，为微服务的发展贡献了不少力量。但是，在实践中也会遇到不少问题和挑战，包括配置管理、调用链跟踪、数据一致性等方面，需要我们不断地进行探索和实践，以解决这些难题。

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