Kubernetes/Spring Cloud Dataflow stream > spring.cloud.stream.bindings.output.destination is ignored by producer

Question

I'm trying to run a "Hello, world" Spring Cloud Data Flow stream based on the very simple example explained at http://cloud.spring.io/spring-cloud-dataflow/. I'm able to create a simple source and sink and run it on my local SCDF server using Kafka, so until here everything is correct and messages are produced and consumed in the topic specified by SCDF.

Now, I'm trying to deploy it in my private cloud based on the instructions listed at http://docs.spring.io/spring-cloud-dataflow-server-kubernetes/docs/current-SNAPSHOT/reference/htmlsingle/#_getting_started. Using this deployment I'm able to deploy a simple "time | log" out-of-the-box stream with no problems, but my example fails since the producer is not writing in the topic specified when the pod is created (for instance, spring.cloud.stream.bindings.output.destination=ntest33.nites-source9) but in the topic "output". I have a similar problem with the sink component, which creates and expect messages in the topic "input".

I created the stream definition using the dashboard:

nsource1 | log

And container args for the source are:

--spring.cloud.stream.bindings.output.producer.requiredGroups=ntest34
--spring.cloud.stream.bindings.output.destination=ntest34.nsource1

Code snippet for source component is package xxxx;

import java.text.SimpleDateFormat;
import java.util.Date;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.stream.annotation.EnableBinding;
import org.springframework.cloud.stream.messaging.Source;
import org.springframework.context.annotation.Bean;
import org.springframework.integration.annotation.InboundChannelAdapter;
import org.springframework.integration.core.MessageSource;
import org.springframework.messaging.support.GenericMessage;

@SpringBootApplication
@EnableBinding(Source.class)
public class HelloNitesApplication
{
public static void main(String[] args)
{
    SpringApplication.run(HelloNitesApplication.class, args);
}

@Bean
@InboundChannelAdapter(value = Source.OUTPUT)
public MessageSource<String> timerMessageSource()
{
    return () -> new GenericMessage<>("Hello " + new SimpleDateFormat().format(new Date()));
}

And in the logs I can see clearly

2017-04-07T09:44:34.596842965Z 2017-04-07 09:44:34,593 INFO main o.s.i.c.DirectChannel:81 - Channel 'application.output' has 1 subscriber(s).

Question is, how to override properly the topic where messages must be produced/consumed or what attribute and values to use to make this work on k8s?

UPDATE: I have the similar problem using RabbitMQ

2017-04-07T12:56:40.435405177Z 2017-04-07 12:56:40.435 INFO 7 --- [ main] o.s.integration.channel.DirectChannel : Channel 'application.output' has 1 subscriber(s).

Answer 1

The problem was with my docker image. I still don't know the details but using the Dockerfile indicated at https://spring.io/guides/gs/spring-boot-docker/ instantiated 2 processes in the docker container, one with the parameters, and other without, which was the one with uptime and therefore being used.

The solution was to replace

ENTRYPOINT [ "sh", "-c", "java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /app.jar" ]

With

ENTRYPOINT [ "java", "-jar", "/app.jar" ]

And it started working. There must be a good reason why the example indicated the first entrypoint and why 2 processes were created, but the reason is still beyond my understanding.