Spring Cloud Stream - Functions - How to manually acknowledge rabbitmq message? - spring-integration

Question

I'm using a spring cloud stream with rabbitbinder.
Using a #StreamListener, I could manually acknowledge rabbitmq messages by having Channel and deliveryTag injected into the method as follows:
#StreamListener(target = MySink.INPUT1)
public void listenForInput1(Message<String> message,
#Header(AmqpHeaders.CHANNEL) Channel channel,
#Header(AmqpHeaders.DELIVERY_TAG) Long deliveryTag) throws IOException {
log.info(" received new message [" + message.toString() + "] ");
channel.basicAck(deliveryTag, false);
}
I am now trying to achieve the same using functions:
#Bean
public Consumer<Message<String>> sink1() {
return message -> {
System.out.println("******************");
System.out.println("At Sink1");
System.out.println("******************");
System.out.println("Received message " + message.getPayload());
};
}
How do I get the Channel object in here so that I can acknowledge it with the deliveryTag?
I am able to get the delivery tag form headers. However, I am unable to get the channel Object.

Answer 1

I was able to figure it out:
#Bean
public Consumer<Message<String>> sink1() {
return message -> {
System.out.println("******************");
System.out.println("At Sink1");
System.out.println("******************");
System.out.println("Received message " + message.getPayload());
Channel channel = message.getHeaders().get(AmqpHeaders.CHANNEL, Channel.class);
Long deliveryTag = message.getHeaders().get(AmqpHeaders.DELIVERY_TAG, Long.class);
try {
channel.basicAck(deliveryTag, false);
} catch (IOException e) {
e.printStackTrace();
}
};
}