4. 服务实例
<ServiceBrokersAreResponsibleForProvisioningTheServicesAdvertisedInTheirCatalogAndManagingTheirLifecycleInTheUnderlyingCloudPlatform.</br /><TheServicesCreatedByTheBrokerAreReferredToAsServiceInstances.
服务代理必须实现 ServiceInstanceService 接口，并提供该接口所需方法的实现。
每个方法接收一个包含来自平台的请求所有详细信息的Java对象参数，并返回一个Java对象值，向平台提供操作的详细信息。
服务实例创建、更新和删除操作可以同步或异步执行。
-
当服务代理创建、更新或删除服务实例同步时，相应的接口方法应该阻塞，并在操作成功完成，或在发生失败时才向平台返回响应。
-
在执行异步操作时，服务代理可以在操作完成前向平台返回响应，并在响应中表明该操作正在进行中。当指示为异步操作时，平台 轮询服务代理 以获取该操作的状态。
4.1. 服务实例创建
服务代理必须提供 createServiceInstance() 方法的实现。
服务代理在创建服务实例时通常会在平台或在另一系统中提供资源。 服务代理负责跟踪与服务实例关联的任何资源，以便于后续的检索、更新或删除。
4.1.1. 事件注册表
可以使用事件进一步自定义服务实例创建。</p><p>要做到这一点：
-
Autowire the
CreateServiceInstanceEventFlowRegistrybean. -
使用
addInitializationFlow()、addCompletionFlow()或addErrorFlow()方法之一来注册自定义响应式流，在创建服务实例的各种阶段运行。
4.2.服务实例更新
如果在服务目录中设置字段0 ，则服务broker必须提供< a href = "2" >< code >3 方法的实现。 否则，此方法永远不会由平台调用，并且可以使用接口中的默认实现。
服务代理可以修改现有资源的配置，也可以在更新服务实例或部署新资源时进行修改。
4.2.1.事件注册表
服务实例更新可以通过利用事件进一步自定义。 要做到这一点：
-
Autowire the
UpdateServiceInstanceEventFlowRegistrybean. -
使用
addInitializationFlow()addCompletionFlow()addErrorFlow()中的任何一个方法来注册自定义反应流，以在更新服务实例的各种阶段运行。
4.3. 服务实例删除
一个服务代理的实现必须提供
deleteServiceInstance()
方法。
在创建操作中提供的任何资源都应由删除操作进行去 provisioning。
4.3.1. 事件注册表
可以通过利用事件来进一步自定义服务实例的删除。为此：
-
Autowire the
DeleteServiceInstanceEventFlowRegistrybean. -
使用
addInitializationFlow()、addCompletionFlow()或addErrorFlow()方法之一来注册在删除服务实例的各种阶段运行的自定义反应流。
4.4. 服务实例操作状态检索
如果任何创建、更新或删除操作可以向平台返回“操作正在进行”的异步响应，服务 broker 必须提供对 getLastOperation() 方法的实现。 否则，此方法永远不会被平台调用，可以在接口中使用默认实现。
平台轮询此方法服务 broker，获取具有异步操作的 service 实例，直到 service broker 表示操作已完成成功或发生故障。
4.4.1.事件注册表
服务实例最后操作请求可以通过利用事件进一步自定义。
-
Autowire the
AsyncOperationServiceInstanceEventFlowRegistrybean. -
使用
addInitializationFlow()、addCompletionFlow()或addErrorFlow()方法之一注册在检索操作的各个阶段运行的自定义反应流。
Spring Cloud Netflix如何查找服务实例
如果在服务目录中将instances_retrievable字段设置为true,则服务broker必须提供getServiceInstance()方法的实现。否则,该方法不会由平台调用,可以使用接口中的默认实现。
服务代理负责维护支持检索操作所需的所有服务实例状态。
4.6. 示例实现
以下示例演示了服务实例实现：
package com.example.servicebroker;
@Service
public class ExampleServiceInstanceService implements ServiceInstanceService {
@Override
public Mono<CreateServiceInstanceResponse> createServiceInstance(CreateServiceInstanceRequest request) {
String serviceInstanceId = request.getServiceInstanceId();
String planId = request.getPlanId();
Map<String, Object> parameters = request.getParameters();
//
// perform the steps necessary to initiate the asynchronous
// provisioning of all necessary resources
//
String dashboardUrl = ""; /* construct a dashboard URL */
return Mono.just(CreateServiceInstanceResponse.builder()
.dashboardUrl(dashboardUrl)
.async(true)
.build());
}
@Override
public Mono<UpdateServiceInstanceResponse> updateServiceInstance(UpdateServiceInstanceRequest request) {
String serviceInstanceId = request.getServiceInstanceId();
String planId = request.getPlanId();
String previousPlan = request.getPreviousValues().getPlanId();
Map<String, Object> parameters = request.getParameters();
//
// perform the steps necessary to initiate the asynchronous
// updating of all necessary resources
//
return Mono.just(UpdateServiceInstanceResponse.builder()
.async(true)
.build());
}
@Override
public Mono<DeleteServiceInstanceResponse> deleteServiceInstance(DeleteServiceInstanceRequest request) {
String serviceInstanceId = request.getServiceInstanceId();
String planId = request.getPlanId();
//
// perform the steps necessary to initiate the asynchronous
// deletion of all provisioned resources
//
return Mono.just(DeleteServiceInstanceResponse.builder()
.async(true)
.build());
}
@Override
public Mono<GetServiceInstanceResponse> getServiceInstance(GetServiceInstanceRequest request) {
String serviceInstanceId = request.getServiceInstanceId();
//
// retrieve the details of the specified service instance
//
String dashboardUrl = ""; /* retrieve dashboard URL */
return Mono.just(GetServiceInstanceResponse.builder()
.dashboardUrl(dashboardUrl)
.build());
}
@Override
public Mono<GetLastServiceOperationResponse> getLastOperation(GetLastServiceOperationRequest request) {
String serviceInstanceId = request.getServiceInstanceId();
//
// determine the status of the operation in progress
//
return Mono.just(GetLastServiceOperationResponse.builder()
.operationState(OperationState.SUCCEEDED)
.build());
}
}
4.7. 示例事件流配置
配置服务实例事件流有多种方法。<br>一种是通过自动装配一个或多个注册表并直接与注册表交互。<br>另一种是为特定流程定义bean。<br>这些bean会自动被识别并添加到适当的注册表中。<br>最后一种方法是声明一个新的注册表bean。<br>但是请注意，定义新的注册表bean会覆盖提供的自动配置。
4.7.1. 选项1：自动装配注册表
下面的例子显示了服务实例事件流的配置：
package com.example.servicebroker;
@Configuration
public class ExampleServiceInstanceEventFlowsConfiguration {
private final CreateServiceInstanceEventFlowRegistry createRegistry;
private final UpdateServiceInstanceEventFlowRegistry updateRegistry;
private final DeleteServiceInstanceEventFlowRegistry deleteRegistry;
private final AsyncOperationServiceInstanceEventFlowRegistry asyncRegistry;
public ExampleServiceInstanceEventFlowsConfiguration(CreateServiceInstanceEventFlowRegistry createRegistry,
UpdateServiceInstanceEventFlowRegistry updateRegistry,
DeleteServiceInstanceEventFlowRegistry deleteRegistry,
AsyncOperationServiceInstanceEventFlowRegistry asyncRegistry) {
this.createRegistry = createRegistry;
this.updateRegistry = updateRegistry;
this.deleteRegistry = deleteRegistry;
this.asyncRegistry = asyncRegistry;
prepareCreateEventFlows()
.then(prepareUpdateEventFlows())
.then(prepareDeleteEventFlows())
.then(prepareLastOperationEventFlows())
.subscribe();
}
private Mono<Void> prepareCreateEventFlows() {
return Mono.just(createRegistry)
.map(registry -> registry.addInitializationFlow(new CreateServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(CreateServiceInstanceRequest request) {
//
// do something before the instance is created
//
return Mono.empty();
}
})
.then(registry.addCompletionFlow(new CreateServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(CreateServiceInstanceRequest request,
CreateServiceInstanceResponse response) {
//
// do something after the instance is created
//
return Mono.empty();
}
}))
.then(registry.addErrorFlow(new CreateServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(CreateServiceInstanceRequest request, Throwable t) {
//
// do something if an error occurs while creating an instance
//
return Mono.empty();
}
})))
.then();
}
private Mono<Void> prepareUpdateEventFlows() {
return Mono.just(updateRegistry)
.map(registry -> registry.addInitializationFlow(new UpdateServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(UpdateServiceInstanceRequest request) {
//
// do something before the instance is updated
//
return Mono.empty();
}
})
.then(registry.addCompletionFlow(new UpdateServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(UpdateServiceInstanceRequest request,
UpdateServiceInstanceResponse response) {
//
// do something after the instance is updated
//
return Mono.empty();
}
}))
.then(registry.addErrorFlow(new UpdateServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(UpdateServiceInstanceRequest request, Throwable t) {
//
// do something if an error occurs while updating an instance
//
return Mono.empty();
}
})))
.then();
}
private Mono<Void> prepareDeleteEventFlows() {
return Mono.just(deleteRegistry)
.map(registry -> registry.addInitializationFlow(new DeleteServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(DeleteServiceInstanceRequest request) {
//
// do something before the instance is deleted
//
return Mono.empty();
}
})
.then(registry.addCompletionFlow(new DeleteServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(DeleteServiceInstanceRequest request,
DeleteServiceInstanceResponse response) {
//
// do something after the instance is deleted
//
return Mono.empty();
}
}))
.then(registry.addErrorFlow(new DeleteServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(DeleteServiceInstanceRequest request, Throwable t) {
//
// do something if an error occurs while deleting an instance
//
return Mono.empty();
}
})))
.then();
}
private Mono<Void> prepareLastOperationEventFlows() {
return Mono.just(asyncRegistry)
.map(registry -> registry.addInitializationFlow(new AsyncOperationServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(GetLastServiceOperationRequest request) {
//
// do something before returning the last operation
//
return Mono.empty();
}
})
.then(registry.addCompletionFlow(new AsyncOperationServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(GetLastServiceOperationRequest request,
GetLastServiceOperationResponse response) {
//
// do something after returning the last operation
//
return Mono.empty();
}
}))
.then(registry.addErrorFlow(new AsyncOperationServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(GetLastServiceOperationRequest request, Throwable t) {
//
// do something if an error occurs while processing the last operation response
//
return Mono.empty();
}
})))
.then();
}
}
4.7.2. 选项 2：事件流 Bean
可选地，您可以为各个流配置 bean，如下所示：
package com.example.servicebroker;
@Configuration
public class ExampleServiceInstanceEventFlowsConfiguration2 {
//
// Create Service Instance flows
//
@Bean
public CreateServiceInstanceInitializationFlow createServiceInstanceInitializationFlow() {
return new CreateServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(CreateServiceInstanceRequest request) {
//
// do something before the instance is created
//
return Mono.empty();
}
};
}
@Bean
public CreateServiceInstanceCompletionFlow createServiceInstanceCompletionFlow() {
return new CreateServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(CreateServiceInstanceRequest request,
CreateServiceInstanceResponse response) {
//
// do something after the instance is created
//
return Mono.empty();
}
};
}
@Bean
public CreateServiceInstanceErrorFlow createServiceInstanceErrorFlow() {
return new CreateServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(CreateServiceInstanceRequest request, Throwable t) {
//
// do something if an error occurs while creating an instance
//
return Mono.empty();
}
};
}
//
// Update Service Instance flows
//
@Bean
public UpdateServiceInstanceInitializationFlow updateServiceInstanceInitializationFlow() {
return new UpdateServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(
UpdateServiceInstanceRequest request) {
//
// do something before the instance is updated
//
return Mono.empty();
}
};
}
@Bean
public UpdateServiceInstanceCompletionFlow updateServiceInstanceCompletionFlow() {
return new UpdateServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(UpdateServiceInstanceRequest request,
UpdateServiceInstanceResponse response) {
//
// do something after the instance is updated
//
return Mono.empty();
}
};
}
@Bean
public UpdateServiceInstanceErrorFlow updateServiceInstanceErrorFlow() {
return new UpdateServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(UpdateServiceInstanceRequest request, Throwable t) {
//
// do something if an error occurs while updating an instance
//
return Mono.empty();
}
};
}
//
// Delete Service Instance flows
//
@Bean
public DeleteServiceInstanceInitializationFlow deleteServiceInstanceInitializationFlow() {
return new DeleteServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(
DeleteServiceInstanceRequest request) {
//
// do something before the instance is deleted
//
return Mono.empty();
}
};
}
@Bean
public DeleteServiceInstanceCompletionFlow deleteServiceInstanceCompletionFlow() {
return new DeleteServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(DeleteServiceInstanceRequest request,
DeleteServiceInstanceResponse response) {
//
// do something after the instance is deleted
//
return Mono.empty();
}
};
}
@Bean
public DeleteServiceInstanceErrorFlow deleteServiceInstanceErrorFlow() {
return new DeleteServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(DeleteServiceInstanceRequest request, Throwable t) {
//
// do something if an error occurs while deleting the instance
//
return Mono.empty();
}
};
}
//
// Get Last Operation flows
//
@Bean
public AsyncOperationServiceInstanceInitializationFlow getLastOperationInitializationFlow() {
return new AsyncOperationServiceInstanceInitializationFlow() {
@Override
public Mono<Void> initialize(
GetLastServiceOperationRequest request) {
//
// do something before getting the last operation
//
return Mono.empty();
}
};
}
@Bean
public AsyncOperationServiceInstanceCompletionFlow getLastOperationCompletionFlow() {
return new AsyncOperationServiceInstanceCompletionFlow() {
@Override
public Mono<Void> complete(GetLastServiceOperationRequest request,
GetLastServiceOperationResponse response) {
//
// do something after getting the last operation
//
return Mono.empty();
}
};
}
@Bean
public AsyncOperationServiceInstanceErrorFlow getLastOperationErrorFlow() {
return new AsyncOperationServiceInstanceErrorFlow() {
@Override
public Mono<Void> error(GetLastServiceOperationRequest request, Throwable t) {
//
// do something if an error occurs while getting the last operation
//
return Mono.empty();
}
};
}
}