examples/python/high-level/consumer.py

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# to you under the Apache License, Version 2.0 (the
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#
#   http://www.apache.org/licenses/LICENSE-2.0
#
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import argparse
import asyncio
from datetime import timedelta
from typing import NamedTuple

from apache_iggy import (
    AutoCommit,
    AutoCommitAfter,
    IggyClient,
    PollingStrategy,
    ReceiveMessage,
)
from loguru import logger

STREAM_NAME = "high-level-stream"
TOPIC_NAME = "high-level-topic"
CONSUMER_GROUP_NAME = "high-level-consumer"
MESSAGES_TO_CONSUME = 12


class ArgNamespace(NamedTuple):
    connection_string: str


def parse_args() -> ArgNamespace:
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "connection_string",
        help=(
            "Connection string for Iggy, for example "
            "'iggy+tcp://iggy:iggy@127.0.0.1:8090'"
        ),
        default="iggy+tcp://iggy:iggy@127.0.0.1:8090",
        nargs="?",
    )
    return ArgNamespace(**vars(parser.parse_args()))


async def main() -> None:
    args = parse_args()
    client = IggyClient.from_connection_string(args.connection_string)

    logger.info("Connecting to Iggy")
    await client.connect()

    consumer = await client.consumer_group(
        CONSUMER_GROUP_NAME,
        STREAM_NAME,
        TOPIC_NAME,
        polling_strategy=PollingStrategy.First(),
        batch_length=100,
        auto_commit=AutoCommit.After(AutoCommitAfter.ConsumingEachMessage()),
        poll_interval=timedelta(milliseconds=100),
    )

    shutdown_event = asyncio.Event()
    consumed_messages = 0

    async def handle_message(message: ReceiveMessage) -> None:
        nonlocal consumed_messages
        consumed_messages += 1
        logger.info(
            "Received message from partition {} at offset {}: {}",
            message.partition_id(),
            message.offset(),
            message.payload().decode("utf-8"),
        )
        if consumed_messages == MESSAGES_TO_CONSUME:
            shutdown_event.set()

    await consumer.consume_messages(handle_message, shutdown_event)
    logger.info("Consumed {} messages, exiting", consumed_messages)


if __name__ == "__main__":
    asyncio.run(main())