Switch to last message in Kafka topic on start consuming

[dimbler]

Dear Team,
Please clarify how can it possible to seek to end of the Kafka topic partition on subscriber startup?

[Lancetnik]

If you are using raw FastStream subscriber, it uses auto_offset_reset="latest" already and should read the messages since the moment it started

[dimbler]

Dear Lancetnik,
Thank you for the rapid answer.
If you metioned about first start, it has been worked, but we need read only last message in topic on every application start. Regardless of whether new messages have appeared or not.

[Lancetnik]

Do you want to just getone latest message and doesn't consume whole stream?

[Lancetnik]

You can make it manually by

subscriber = broker.subscriber("test-topic")

@subscriber  # regular handler
async def handler(): ...

@app.after_startup
async def get_last_msg():
    await subscriber.get_msg()
    # or by access to raw consumer
    await subscriber.consumer.getone()