What’s the best way to work with message sequence numbers to ensure order and completeness?

Our recommendation for handling/processing with message sequence is as follows:

On beginning of day (one system event messages): Reset variable to 0;

(processMessageNumber=0)

On every other message:

If(messageSequnceNumber <= processMessageNumber) { Ignore message; }

Else If (messageSequnceNumber > processMessageNumber+1) {

LOG WARN (GAP DATA); }

Else {

processMessageNumber = messageSequnceNumber

ProcessMessage(BusinessLogic) }

We recommend this approach as Kafka (or any distributed system) can have dupes. We are working on reducing this from happening, but it can happen given the distributed nature of Kafka.