examples/rust/src/basic/consumer/main.rs

/* Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
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 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
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use iggy::prelude::*;
use iggy_examples::shared::args::Args;
use iggy_examples::shared::system;
use std::error::Error;
use std::sync::Arc;
use tracing::info;
use tracing_subscriber::layer::SubscriberExt;
use tracing_subscriber::util::SubscriberInitExt;
use tracing_subscriber::{EnvFilter, Registry};

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let args = Args::parse_with_defaults("basic-consumer");
    Registry::default()
        .with(tracing_subscriber::fmt::layer())
        .with(EnvFilter::try_from_default_env().unwrap_or(EnvFilter::new("INFO")))
        .init();
    info!(
        "Basic 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_client(client_provider_config, false).await?;
    let client = IggyClient::new(client);
    client.connect().await?;
    system::init_by_consumer(&args, &client).await;
    system::consume_messages(&args, &client, &handle_message).await
}

fn handle_message(message: &IggyMessage) -> Result<(), Box<dyn Error>> {
    // The payload can be of any type as it is a raw byte array. In this case it's a simple string.
    let payload = std::str::from_utf8(&message.payload)?;
    info!(
        "Handling message at offset: {}, payload: {}...",
        message.header.offset, payload
    );
    Ok(())
}