Back-port support for BindingsLifecycleController getExtensionProperties to 4.1.x

[jmannix-ot]

Is it possible to get this feature back-ported to 4.1.x? See #3071

Thank you,
John

[olegz]

Backported - https://github.com/spring-cloud/spring-cloud-stream/commits/4.1.x

[olegz]

Please test it out and let me know

[jmannix-ot]

Thanks Oleg. One thing we need to be able to do is generate new bindings at runtime, and I don't think that is currently possible with the BindingLifecycleController?

So we have some consumers configured only via our library's configuration properties, and for each of these we currently add a consumer binding by building a map of KafkaBindingProperties and calling kafkaExtendedBindingProperties.setBindings(map).

Is there a way to achieve this? Or would it require more customisation of the BindingsLifecycleController.

[olegz]

I am assuming this is new functionality request, correct? If so there are couple of possibilities, but i want to understand the use case better. You can also look at the StreamBridge as the way to send messages to dynamically generated bindings

[jmannix-ot]

Ok, so what we do right now is:

Autowire KafkaExtendedBindingProperties:

@Autowired
    private KafkaExtendedBindingProperties kafkaExtendedBindingProperties;

Make a copy of all the bindings:

        final Map<String, KafkaBindingProperties> kafkaBindings =
                new HashMap<>(kafkaExtendedBindingProperties.getBindings());

For each configured consumer, fetch the existing binding or create a new one if one doesn't exist:

KafkaBindingProperties bindingProperties = kafkaBindings.get(key);
            if (bindingProperties == null) {
                bindingProperties = new KafkaBindingProperties();
            }

Make changes to the consumer properties and then update our bindings map:

            bindingProperties.setConsumer(consumerProperties);
            kafkaBindings.put(key, bindingProperties);

Finally set the bindings back on KafkaExtendedBindingProperties:

        kafkaExtendedBindingProperties.setBindings(
                ImmutableMap.<String, KafkaBindingProperties>builder()
                        .putAll(kafkaBindings)
                        .build());

So we are looking to achieve the same thing by using a properly supported API.

Thanks,
John