没有 Spring-boot 的 Eureka 服务发现

Question

我写了一个spring boot微服务和一个REST客户端。客户端是另一个模块的一部分，并对微服务进行 RESTful 调用。微服务注册到 Eureka 注册中心，我希望我的客户端（不是 Spring Boot 项目）使用 Eureka 来查询和获取服务端点。

我的问题是由于客户端不是 Spring-Boot 应用程序，我不能使用 @SpringBootApplication、@EnableDiscoveryClient 和 DiscoveryClient 等注释，而 DiscoveryClient 没有自动连接到应用程序。无论如何手动将DiscoveryClient bean 自动连接到客户端而不使用注释？

Answer 1

嗯，我就是这样做的。基本上它比我预期的要容易得多。以下内容抄自Netflix eureka project.

  DiscoveryManager.getInstance().initComponent(new MyDataCenterInstanceConfig(), new DefaultEurekaClientConfig());

  String vipAddress = "MY-SERVICE";

    InstanceInfo nextServerInfo = null;
    try {
        nextServerInfo = DiscoveryManager.getInstance()
                .getEurekaClient()
                .getNextServerFromEureka(vipAddress, false);
    } catch (Exception e) {
        System.err.println("Cannot get an instance of example service to talk to from eureka");
        System.exit(-1);
    }

    System.out.println("Found an instance of example service to talk to from eureka: "
            + nextServerInfo.getVIPAddress() + ":" + nextServerInfo.getPort());

    System.out.println("healthCheckUrl: " + nextServerInfo.getHealthCheckUrl());
    System.out.println("override: " + nextServerInfo.getOverriddenStatus());

    System.out.println("Server Host Name "+ nextServerInfo.getHostName() + " at port " + nextServerInfo.getPort() );

您还必须将配置文件添加到类路径。 Eureka 客户端使用该文件读取有关 eureka 服务器的信息。

eureka.preferSameZone=true
eureka.shouldUseDns=false
eureka.serviceUrl.default=http://localhost:8761/eureka/
eureka.decoderName=JacksonJson

您还必须提供 eureka 客户端作为依赖项。 Eureka1 支持 JDK7，尽管它的某些部分是用 JDK8 构建的。但是，我必须提供旧版本的“archaius-core”和“servo-core”才能使其与 JDK7 一起运行。

    <dependency>
        <groupId>com.netflix.archaius</groupId>
        <artifactId>archaius-core</artifactId>
        <version>0.7.3</version>
    </dependency>
    <dependency>
        <groupId>com.netflix.servo</groupId>
        <artifactId>servo-core</artifactId>
        <version>0.10.0</version>
    </dependency>

Eureka2 完全支持 JDK7。

Answer 2

要么你使用 netflix-eureka-client 没有 spring-cloud 并且必须自己配置所有（这意味着复制 EurekaDiscoveryClientConfiguration）

或者您可以运行边车服务。 Sidecar 包含一个 zuul-proxy，它将代理 eureka 发现的服务。看看Spring Cloud Docs - Polyglot support with Sidecar

Answer 3

希望从传统 spring（非引导）访问 Eureka 也变得像 @EnableEureka 和 @EnableFeignClient 一样简单

这是我可以让它工作的最接近的。此示例在 Git Hub 中的 Eureka-examples 中可用

public class EurekaConfiguration {

    private static ApplicationInfoManager applicationInfoManager;
    private static EurekaClient eurekaClient;

    private static synchronized ApplicationInfoManager initializeApplicationInfoManager(
            EurekaInstanceConfig instanceConfig) {
        if (applicationInfoManager == null) {
            InstanceInfo instanceInfo = new EurekaConfigBasedInstanceInfoProvider(instanceConfig).get();
            applicationInfoManager = new ApplicationInfoManager(instanceConfig, instanceInfo);
        }

        return applicationInfoManager;
    }

    private static synchronized EurekaClient initializeEurekaClient(ApplicationInfoManager applicationInfoManager,
            EurekaClientConfig clientConfig) {
        if (eurekaClient == null) {
            eurekaClient = new DiscoveryClient(applicationInfoManager, clientConfig);
        }

        return eurekaClient;
    }
    
    public static EurekaClient getEurekaClient()
    {
        ApplicationInfoManager applicationInfoManager = initializeApplicationInfoManager(new MyDataCenterInstanceConfig());
        EurekaClient client = initializeEurekaClient(applicationInfoManager, new DefaultEurekaClientConfig());
        return client;
    }
}

我的客户

String vipAddress = "NLPService";

        InstanceInfo nextServerInfo = null;
        try {
            nextServerInfo = EurekaConfiguration.getEurekaClient().getNextServerFromEureka(vipAddress, false);
        } catch (Exception e) {
            System.err.println("Cannot get an instance of example service to talk to from eureka");
            System.exit(-1);
        }

        System.out.println("Found an instance of example service to talk to from eureka: "
                + nextServerInfo.getVIPAddress() + ":" + nextServerInfo.getPort());
        
        String serviceBaseURL = "http://"+ nextServerInfo.getHostName()
        +":"+nextServerInfo.getPort();
       
        
        String nlpServiceURL = serviceBaseURL +"/nlp";
        
        RestTemplate restTemplate = new RestTemplate();
        
        NLPInputToBeTransformed input = new NLPInputToBeTransformed();
        input.setInputText(" Test Input ");
        
        
        NLPResponse nlpResponse = restTemplate.postForObject
                (nlpServiceURL, input, NLPResponse.class, new HashMap<>());
        
        System.out.println( " Service Response  " + nlpResponse.getTags());