Spring Serverless HTTP Poller

Question

I want to implement a serverless function that polls an HTTP endpoint and publishes the response to a messaging queue.

My initial thought is to build a spring boot application using spring integration gateway and adapters for HTTP polling and publishing to queue (and deploy as lambda). Is there a better option in the spring stack?

I looked at spring cloud function, spring cloud stream, spring cloud task. Any suggestions?

Answer 1

In Spring Cloud Stream this type of microservice is called source. So, you need to have a Supplier bean based on Spring Integration Java DSL to build a simple flow to let Spring Cloud Stream to poll it periodically and produce a result into bound destination.

Something like this:

    @Bean
    public IntegrationFlow pollingHttpFlow() {
        return IntegrationFlows
                .from(Supplier.class, gateway -> gateway.beanName("httpSupplier"))
                .handle(Http.outboundGateway("http://somehost"))
                .get();
    }

See a blog post about this kind of interoperability: https://spring.io/blog/2019/10/25/spring-cloud-stream-and-spring-integration