examples/src/new-sdk/consumer/main.rs

use clap::Parser;
use futures_util::StreamExt;
use iggy::client_provider;
use iggy::client_provider::ClientProviderConfig;
use iggy::clients::client::IggyClient;
use iggy::clients::consumer::{AutoCommit, AutoCommitWhen, IggyConsumer, ReceivedMessage};
use iggy::consumer::ConsumerKind;
use iggy::messages::poll_messages::PollingStrategy;
use iggy::utils::duration::IggyDuration;
use iggy_examples::shared::args::Args;
use iggy_examples::shared::messages::{
    Envelope, OrderConfirmed, OrderCreated, OrderRejected, ORDER_CONFIRMED_TYPE,
    ORDER_CREATED_TYPE, ORDER_REJECTED_TYPE,
};
use std::error::Error;
use std::str::FromStr;
use std::sync::Arc;
use tracing::{error, info, warn};

#[tokio::main]
async fn main() -> anyhow::Result<(), Box<dyn Error>> {
    let args = Args::parse();
    tracing_subscriber::fmt::init();
    info!(
        "New SDK consumer has started, selected transport: {}",
        args.transport
    );
    let client_provider_config = Arc::new(ClientProviderConfig::from_args(args.to_sdk_args())?);
    let client = client_provider::get_raw_connected_client(client_provider_config).await?;
    let client = IggyClient::new(client);

    let name = "new-sdk-consumer";
    let mut consumer = match ConsumerKind::from_code(args.consumer_kind)? {
        ConsumerKind::Consumer => {
            client.consumer(name, &args.stream_id, &args.topic_id, args.partition_id)?
        }
        ConsumerKind::ConsumerGroup => {
            client.consumer_group(name, &args.stream_id, &args.topic_id)?
        }
    }
    .auto_commit(AutoCommit::When(AutoCommitWhen::PollingMessages))
    .create_consumer_group_if_not_exists()
    .auto_join_consumer_group()
    .polling_strategy(PollingStrategy::next())
    .poll_interval(IggyDuration::from_str(&args.interval)?)
    .batch_size(args.messages_per_batch)
    .build();

    consumer.init().await?;
    consume_messages(&args, &mut consumer).await?;

    Ok(())
}

pub async fn consume_messages(
    args: &Args,
    consumer: &mut IggyConsumer,
) -> Result<(), Box<dyn Error>> {
    let interval = args.get_interval();
    let mut consumed_batches = 0;

    info!("Messages will be polled by consumer: {} from stream: {}, topic: {}, partition: {} with interval {}.",
        args.consumer_id, args.stream_id, args.topic_id, args.partition_id, interval.map_or("none".to_string(), |i| i.as_human_time_string()));

    while let Some(message) = consumer.next().await {
        if args.message_batches_limit > 0 && consumed_batches == args.message_batches_limit {
            info!("Consumed {consumed_batches} batches of messages, exiting.");
            return Ok(());
        }

        if let Ok(message) = message {
            handle_message(&message)?;
            consumed_batches += 1;
        } else if let Err(error) = message {
            error!("Error while handling message: {error}");
            continue;
        }
    }
    Ok(())
}

fn handle_message(message: &ReceivedMessage) -> anyhow::Result<(), Box<dyn Error>> {
    // The payload can be of any type as it is a raw byte array. In this case it's a JSON string.
    let json = std::str::from_utf8(&message.message.payload)?;
    // The message envelope can be used to send the different types of messages to the same topic.
    let envelope = serde_json::from_str::<Envelope>(json)?;
    info!(
        "Handling message type: {} at offset: {} in partition ID: {} with current offset: {}",
        envelope.message_type, message.message.offset, message.partition_id, message.current_offset,
    );
    match envelope.message_type.as_str() {
        ORDER_CREATED_TYPE => {
            let order_created = serde_json::from_str::<OrderCreated>(&envelope.payload)?;
            info!("{:#?}", order_created);
        }
        ORDER_CONFIRMED_TYPE => {
            let order_confirmed = serde_json::from_str::<OrderConfirmed>(&envelope.payload)?;
            info!("{:#?}", order_confirmed);
        }
        ORDER_REJECTED_TYPE => {
            let order_rejected = serde_json::from_str::<OrderRejected>(&envelope.payload)?;
            info!("{:#?}", order_rejected);
        }
        _ => {
            warn!("Received unknown message type: {}", envelope.message_type);
        }
    }
    Ok(())
}