Why Is My Spring Cloud Function Attempting to Open Local HTTP Connections? - spring-cloud

Question

I'm deploying a rather simple Spring Cloud Function to AWS Lambda and am running into an issue with slow cold starts and occasional failures noted in calling the function once deployed.
First, here is my single class. (Eventually this function will do some domain record lookups against a database, so the name 'domain' is used here fairly liberally. I've also removed any of the actual data handling and am just returning strings.
<< imports >>
#SpringBootConfiguration
public class DomainApplication implements ApplicationContextInitializer<GenericApplicationContext> {
private static Log logger = LogFactory.getLog(DomainApplication.class);
public static void main(String[] args) throws Exception {
FunctionalSpringApplication.run(DomainApplication.class, args);
}
public Supplier<String> domains(){
return () -> {
logger.info("Return a List of Domains");
return "All Domains";
};
}
public Function<String, String> domain() {
return value -> {
logger.info("Return A Single Domains");
return "This Domain" + value;
};
}
#Override
public void initialize(GenericApplicationContext context) {
context.registerBean("domain", FunctionRegistration.class,
() -> new FunctionRegistration<Function<String, String>>(domain())
.type(FunctionType.from(String.class).to(String.class).getType()));
context.registerBean("domains", FunctionRegistration.class,
() -> new FunctionRegistration<Supplier<String>>(domains())
.type(FunctionType.from(String.class).to(String.class).getType()));
}
}
Here's the dependencies of the project:
...
set('springCloudVersion', '2.1.0.RELEASE')
...
implementation "org.springframework.cloud:spring-cloud-function-context:${springCloudVersion}"
implementation "org.springframework.cloud:spring-cloud-starter-function-webflux:${springCloudVersion}"
implementation "org.springframework.cloud:spring-cloud-function-adapter-aws:${springCloudVersion}"
implementation 'com.amazonaws:aws-lambda-java-core:1.2.0'
implementation 'com.amazonaws:aws-lambda-java-events:2.2.6'
testCompile("org.springframework.boot:spring-boot-starter-test:${springCloudVersion}")
Now, when I package and deploy a 'shadowJar' version of the app to AWS Lambda the startup logs show a connection refused failure:
2019-05-14 20:45:21.205 ERROR 1 --- [or-http-epoll-3] reactor.Flux.MonoRepeatPredicate.1 : onError(io.netty.channel.AbstractChannel$AnnotatedConnectException: syscall:getsockopt(..) failed: Connection refused: localhost/127.0.0.1:80)
... is there a reason why the startup would be attempting to connect locally to port 80? (And as importantly - can I shut that off?)

Answer 1

Facing the same issue, already reported to spring cloud team with
https://github.com/spring-cloud/spring-cloud-function/issues/367