Spring 云总线与 AWS Kinesis stream @refreshscope

Question

I read everywhere @RefreshScope for cloud bus applications work with RabbitMQ and Kafka. But in my case, I am using AWS Parameter store. I want all my client instances to be refreshed automatically without rebuilding servers on AWS Console.

I created AWS Eventbridge from Paramstore to notify Kinesis Stream but I am not able to figure out how can it notify all my client nodes instead of load balancer refresh to only one node(instance).

Thank you for responding in advance.

Answer 1

I've never worked with AWS Eventbridge / Kinesis, however:

@RefreshScope is something that belongs to spring cloud and not not AWS.

More precisely, beans defined with this scope will be re-loaded by spring without reloading the whole application context "dynamically" when configuration changes in spring boot cloud configuration service. Usually this means that you don't have to restart the application.

Now, spring boot microservice should be deployed with actuator that exposes refresh endpoint. Calling this endpoint manually will cause all the @RefreshScope beans to reload.

Here is the source code of the RefreshEndpoint :

@Endpoint(id = "refresh")
public class RefreshEndpoint {

    private ContextRefresher contextRefresher;

    public RefreshEndpoint(ContextRefresher contextRefresher) {
        this.contextRefresher = contextRefresher;
    }

    @WriteOperation
    public Collection<String> refresh() {
        Set<String> keys = this.contextRefresher.refresh();
        return keys;
    }

}

As you see, its merely invokes contextRefresher.refresh() , ContextRefresher is a bean that you can inject in your custom code that will listen to the changes coming from AWS Parameter store (it should somehow invoke it directly or maybe send some message that you could consume or something).

If you're using spring-cloud-bus (disclaimer, I've never worked with it) it exposes the bus-refresh endpoint as well (pretty similar mechanism to what I've described), read spring-cloud-bus documentation for more details.

Answer 2

Thank you Team for sharing info.

Here is what I did to make it work. Added these two libraries to my project

    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-stream-binder-kinesis</artifactId>
        <version>1.1.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-bus</artifactId>
    </dependency>

And added these two entries into bootstrap.properties

cloud.aws.region.static=us-east-1
cloud.aws.stack.auto = false

And refreshing using this endpoint (/bus-refresh)