Working loop_fn retries example.

Cargo.toml

[package]
name = "rusoto_cwl_test"
version = "0.1.0"
authors = ["Bittrance <anders.qvist@burtcorp.com>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
futures = "0.1.25"
tokio-core = "0.1.17"
rusoto_core = "0.36.0"
rusoto_logs = "0.36.0"

main.rs

use futures::future::{Future, loop_fn, Loop};
use rusoto_core::{Region, RusotoFuture};
use rusoto_logs::{CloudWatchLogs, CloudWatchLogsClient, DescribeLogStreamsRequest, DescribeLogStreamsResponse, DescribeLogStreamsError};
use tokio_core::reactor::Core;

fn main() {
    let mut core = Core::new().unwrap();
    let desc_streams_req = DescribeLogStreamsRequest {
        log_group_name: "forbidden_group".into(),
        ..Default::default()
    };
    let client = CloudWatchLogsClient::new(Region::EuWest1);
    let task: RusotoFuture<DescribeLogStreamsResponse, DescribeLogStreamsError> = RusotoFuture::from_future(
        loop_fn((client, desc_streams_req, 0u8), |(client, desc_streams_req, mut count)| {
            client.describe_log_streams(desc_streams_req.clone())
                .and_then(|res| Ok(Loop::Break(res)))
                .or_else(move |err| {
                    println!("{:?}", err);
                    count += 1;
                    if count >= 3 {
                        Err(err)
                    } else {
                        Ok(Loop::Continue((client, desc_streams_req, count)))
                    }
                })
        })
    );
    match core.run(task) {
        Ok(item) => println!("item: {:?}", item),
        Err(e) => panic!("Error completing futures: {}", e),
    };
}