aws-lambda-rust-runtime/examples/basic-streaming-response/src/main.rs at a853fb98892316cd73d716d511e50a874bc1914b · aws/aws-lambda-rust-runtime · GitHub

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use lambda_runtime::{
    service_fn,
    streaming::{channel, Body, Response},
    tracing, Error, LambdaEvent,
};
use aws_lambda_json_impl::Value;
use std::{thread, time::Duration};

async fn func(_event: LambdaEvent<Value>) -> Result<Response<Body>, Error> {
    let messages = vec!["Hello", "world", "from", "Lambda!"];

    let (mut tx, rx) = channel();

    tokio::spawn(async move {
        for message in messages.iter() {
            tx.send_data((message.to_string() + "\n").into()).await.unwrap();
            thread::sleep(Duration::from_millis(500));
        }
    });

    Ok(Response::from(rx))
}

#[tokio::main]
async fn main() -> Result<(), Error> {
    // required to enable CloudWatch error logging by the runtime
    tracing::init_default_subscriber();

    lambda_runtime::run(service_fn(func)).await?;
    Ok(())
}