Amazon SQS FIFO Queue send message validation

Question

I am working on using amazon's fifo queue and when I send a message I would like to know if the item was added with my call, or if the message was already in the queue and it just returned true

Answer 1

Assuming you only have one process adding messages to the queue, just keep track of the sequenceNumber from the result (ie: add it to a Set) - once you have X unique sequenceNumbers, you're set (no pun intended).

If you have multiple processes adding messages, you'll need to either

1. ensure the messages sent by each process are unique (and thus can use the same mechanism as single process), or
2. use some mechanism of sharing information between processes
   • doing this option properly is likely more expensive than it's worth, and I'd strongly suggest either designing for option 1, or revisiting the requirement that each process sends exactly X unique messages, especially if "approximately X" is good enough.