spring.cloud.stream.kafka.binder.headers not working as expected

Question

I am trying to use spring.cloud.stream.kafka.binder.headers to transport a custom header that I am setting based upon a previous question.

I have read in the documentation where...

spring.cloud.stream.kafka.binder.headers
The list of custom headers that will be transported by the binder.

Default: empty.

seems to suggest that setting a list (comma separated?) will cause a custom header to get transported in the Message<>, but the header is lost as soon as the kafka write is completed.

My annotation creates the header as a part of the call to the MessagingGateway:

@MessagingGateway(name = "redemptionGateway", defaultRequestChannel = Channels.GATEWAY_OUTPUT, defaultHeaders = @GatewayHeader(name = "orderId", expression = "#gatewayMethod.name"))
public interface RedemptionGateway {
    ...
}

I observe that the header is properly created in the first preSend debug:

2016-08-15 15:09:04 http-nio-8080-exec-2 DEBUG DirectChannel:430 - preSend on channel 'gatewayOutput', message: GenericMessage [payload=x.TrivialRedemption@2d052d2a[orderId=f72b2d9b-4e60-43fa-95d4-1b0b368fe49f], headers={orderId=create, id=5dccea6f-266e-82b9-54c6-57ec441a26ac, timestamp=1471288144882}] - {applicationSystemCode=x, clientIP=0:0:0:0:0:0:0:1, clusterId=Cluster-Id-NA, containerId=Container-Id-NA, correlationId=UNDEFINED, domainName=defaultDomain, hostName=Host-NA, messageId=10.113.21.144-eb8404d0-de93-4f94-80cb-e5b638e8aeef, userId=anonymous, webAnalyticsCorrelationId=|}

But upon the next preSend, the header is missing:

2016-08-15 15:09:05 kafka-binder- DEBUG DirectChannel:430 - preSend on channel 'enrichingInput', message: GenericMessage [payload=x.TrivialRedemption@357bd4dd[orderId=f72b2d9b-4e60-43fa-95d4-1b0b368fe49f], headers={kafka_offset=10, orderId=create, kafka_messageKey=null, kafka_topic=received, kafka_partitionId=0, kafka_nextOffset=11, contentType=application/x-java-object;type=x.TrivialRedemption}] - {}

My properties contain:

    spring.cloud.stream.kafka.binder.headers=orderId

Answer 1

What version of spring-cloud-stream are you using?

I just wrote a quick test case and it worked just fine...

spring.cloud.stream.kafka.binder.headers=bar
spring.cloud.stream.bindings.output.destination=foobar
spring.cloud.stream.bindings.input.destination=foobar
spring.cloud.stream.bindings.input.group=foo

App:

package com.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.stream.annotation.EnableBinding;
import org.springframework.cloud.stream.messaging.Processor;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.integration.support.MessageBuilder;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.MessagingException;

@SpringBootApplication
@EnableBinding(Processor.class)
public class So38961697Application {

    public static void main(String[] args) throws Exception {
        ConfigurableApplicationContext context = SpringApplication.run(So38961697Application.class, args);
        Foo foo = context.getBean(Foo.class);
        foo.start();
        foo.send();
        Thread.sleep(30000);
        context.close();
    }

    @Bean
    public Foo foo() {
        return new Foo();
    }

    private static class Foo {

        @Autowired
        Processor processor;

        public void send() {
            Message<?> m = MessageBuilder.withPayload("foo")
                    .setHeader("bar", "baz")
                    .build();
            processor.output().send(m);
        }

        public void start() {
            this.processor.input().subscribe(new MessageHandler() {

                @Override
                public void handleMessage(Message<?> m) throws MessagingException {
                    System.out.println(m);
                }

            });
        }

    }

}

Result:

GenericMessage [payload=foo, headers={bar=baz, kafka_offset=0, kafka_messageKey=null, kafka_topic=foobar, kafka_partitionId=0, kafka_nextOffset=1, contentType=text/plain}]

The complete project is here.

Edit: See comment, upgrading to 1.0.2.RELEASE solved the issue

EDIT

Add a group to ensure the consumer consumes from the earliest message. See comment below.