SpringCloud's middleware issues

Preface

With the rapid development of the Internet, the architectural idea of ​​microservices has gradually become a trend.

As a leader among many microservice frameworks, SpringCloud provides a rich middleware component, making it more convenient for us to develop and deploy in microservice projects.

This article will introduce some of the more important middleware and usage scenarios in SpringCloud.

1. Eureka

Eureka is a service registration center provided by SpringCloud. Service registration and discovery can be easily achieved through Eureka.

In a distributed system, service registration and service discovery are very important links.

Through heartbeat detection and member list maintenance, Eureka implements the service self-protection mechanism, and removes invalid nodes in time when there are problems with the service, ensuring high availability of the system.

Using Eureka is very simple. You only need to introduce corresponding dependencies into the project and configure the service registration address through the configuration file.

Here is a simple example of usage:

<dependency>
    <groupId></groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    <version>${}</version>
</dependency>

spring:
  application:
    name: eureka-server
server:
  port: 8761
eureka:
  instance:
    hostname: localhost
  client:
    register-with-eureka: false
    fetch-registry: false
    service-url:
      defaultZone: http://localhost:8761/eureka/

2. Ribbon

Ribbon is a load balancing component that allows requests to be load balancing between multiple services, thus achieving high availability and high concurrency of services.

Ribbon provides a variety of load balancing algorithms, such as polling and randomization, and can choose different algorithms according to actual needs.

Using Ribbon in SpringCloud is also very simple. You only need to introduce corresponding dependencies into your project and configure the service list through the configuration file.

Here is a simple example of usage:

<dependency>
  <groupId></groupId>
  <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
  <version>${}</version>
</dependency>

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
payment-service:
  ribbon:
    listOfServers: localhost:8001,localhost:8002,localhost:8003

3. Feign

Feign is a declarative HTTP client that supports object binding for HTTP requests and responses, providing a simpler and easier way to call REST services.

In SpringCloud, Feign combines Ribbon and Hystrix, making it easier for us to implement service interface calls and fault-tolerant processing.

Using Feign is also very simple. You only need to introduce corresponding dependencies into the project and enable Feign function.

Here is a simple example of usage:

<dependency>
  <groupId></groupId>
  <artifactId>spring-cloud-starter-openfeign</artifactId>
  <version>${}</version>
</dependency>

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
feign:
  client:
    config:
      default:
        connectTimeout: 5000
        readTimeout: 5000
  hystrix:
    enabled: true

@FeignClient(value = "payment-service")
public interface PaymentService {

    @GetMapping("/payment/{id}")
    String getPayment(@PathVariable("id") Long id);
}

4. Hystrix

Hystrix is ​​a fuse component that quickly and reliably handles delays and failures occurring in distributed systems.

Hystrix uses circuit breaker mode to automatically switch to backup service when a service fails, avoiding service bottlenecks and thus ensuring system stability.

Using Hystrix in SpringCloud is also very simple. You only need to introduce corresponding dependencies into the project and configure the information and business logic related to the circuit breaker through annotation.

Here is a simple example of usage:

<dependency>
  <groupId></groupId>
  <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
  <version>${}</version>
</dependency>

hystrix:
  command:
    default:
      execution:
        isolation:
          strategy: SEMAPHORE
          semaphore:
            maxConcurrentRequests: 50
      circuitBreaker:
        requestVolumeThreshold: 20
        sleepWindowInMilliseconds: 5000
        errorThresholdPercentage: 50

@Service
public class PaymentServiceImpl implements PaymentService {

    @Override
    @HystrixCommand(fallbackMethod = "fallbackPayment")
    public String getPayment(Long id) {
        // ......
    }

    public String fallbackPayment(Long id) {
        return "Payment service is unavailable.";
    }
}

5. Zuul

Zuul is a gateway component that forwards requests to different microservices through routing and filtering.

Zuul provides a rich range of routing rules and filters, which can implement functions such as control and forwarding of requests, monitoring and tracking of requests.

Using Zuul in SpringCloud is also very simple. You only need to introduce corresponding dependencies into the project and configure the gateway-related information through the configuration file.

Here is a simple example of usage:

<dependency>
  <groupId></groupId>
  <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
  <version>${}</version>
</dependency>

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
zuul:
  routes:
    user-service:
      path: /user/**
      serviceId: user-service

In the above configuration, we will use all request paths to/user/**All requests at the beginning are forwarded to the user-service microservice.

Conclusion

This article only introduces some more important SpringCloud middleware components, and there are many other middleware components, such as Config, Bus, etc., readers can further explore.

Through these middleware components provided by SpringCloud, we can more conveniently develop highly available, high-performance, and high-concurrency microservice systems.

The above is personal experience. I hope you can give you a reference and I hope you can support me more.