examples/python/getting-started/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
import typing
import urllib
import urllib.parse
from collections import namedtuple

from apache_iggy import IggyClient, PollingStrategy, ReceiveMessage
from loguru import logger

STREAM_NAME = "sample-stream"
TOPIC_NAME = "sample-topic"
STREAM_ID = 0
TOPIC_ID = 0
PARTITION_ID = 0
BATCHES_LIMIT = 5

ArgNamespace = namedtuple("ArgNamespace", ["tcp_server_address"])


class ValidateUrl(argparse.Action):
    def __call__(
        self,
        parser: argparse.ArgumentParser,
        namespace: argparse.Namespace,
        values: typing.List[typing.Any],
        option_string: str | None = None,
    ):
        parsed_url: urllib.parse.ParseResult = urllib.parse.urlparse("//" + values)
        if parsed_url.netloc == "" or parsed_url.path != "":
            parser.error(f"Invalid server address: {values}")
        setattr(namespace, self.dest, values)


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--tcp-server-address",
        help="Iggy TCP server address (host:port)",
        action=ValidateUrl,
        default="127.0.0.1:8090",
    )
    return parser.parse_args()


async def main():
    args: ArgNamespace = parse_args()
    client = IggyClient(args.tcp_server_address)
    try:
        logger.info("Connecting to IggyClient...")
        await client.connect()
        logger.info("Connected. Logging in user...")
        await client.login_user("iggy", "iggy")
        logger.info("Logged in.")
        await consume_messages(client)
    except Exception as error:
        logger.exception("Exception occurred in main function: {}", error)


async def consume_messages(client: IggyClient):
    interval = 0.5  # 500 milliseconds in seconds for asyncio.sleep
    logger.info(
        f"Messages will be consumed from stream: {STREAM_NAME}, topic: {TOPIC_NAME}, partition: {PARTITION_ID} with "
        f"interval {interval * 1000} ms."
    )
    offset = 0
    messages_per_batch = 10
    n_consumed_batches = 0
    while n_consumed_batches < BATCHES_LIMIT:
        try:
            logger.debug("Polling for messages...")
            polled_messages = await client.poll_messages(
                stream=STREAM_NAME,
                topic=TOPIC_NAME,
                partition_id=PARTITION_ID,
                polling_strategy=PollingStrategy.Next(),
                count=messages_per_batch,
                auto_commit=True,
            )
            if not polled_messages:
                logger.info("No messages found in current poll")
                await asyncio.sleep(interval)
                continue

            offset += len(polled_messages)
            for message in polled_messages:
                handle_message(message)
            n_consumed_batches += 1
            await asyncio.sleep(interval)
        except Exception as error:
            logger.exception("Exception occurred while consuming messages: {}", error)
            break

    logger.info(f"Consumed {n_consumed_batches} batches of messages, exiting.")


def handle_message(message: ReceiveMessage):
    payload = message.payload().decode("utf-8")
    logger.info(
        f"Handling message at offset: {message.offset()} with payload: {payload}..."
    )


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