Allow server acknowledgements after events are published

[ramey]

Problem Summary

Currently, Raccoon sends acknowledgments to the clients after pushing events to BufferChannel and not when published to Kafka. As a result, clients can't retry or resend events in case of downtimes or producer failures.

Proposed solution

Add a configuration parameter EVENT_ACK that allows Raccoon to run in different states. The following states are proposed -

• 0 - events are acknowledged after pushing to BufferChannel
• 1 - events are acknowledged after publishing to Kafka

Impact

Clients are aware of publishing failures and can retry publishing of events.

Which version was this found? NA

Additional context

Increased end-to-end latency in case of EVENT_ACK = 1 as acknowledgments are send after dequeuing from the buffer channel and publishing to Kafka