futures-retry-policies

A crate to help retry futures.

```rust use futuresretrypolicies::{retry, RetryPolicy}; use std::{ops::ControlFlow, time::Duration};

// 1. Create your retry policy

/// Retries a request n times pub struct Retries(usize);

// 2. Define how your policy behaves

impl RetryPolicy> for Retries { fn shouldretry(&mut self, result: Result<(), &'static str>) -> ControlFlow, Duration> { if self.0 > 0 && result.iserr() { self.0 -= 1; // continue to retry on error ControlFlow::Continue(Duration::from_millis(100)) } else { // We've got a success, or we've exhauted our retries, so break ControlFlow::Break(result) } } }

async fn makerequest() -> Result<(), &'static str> { // make a request # static COUNT: std::sync::atomic::AtomicUsize = std::sync::atomic::AtomicUsize::new(0); # if COUNT.fetchadd(1, std::sync::atomic::Ordering::SeqCst) < 2 { Err("fail") } else { Ok(()) } }

[tokio::main]

async fn main() -> Result<(), &'static str> { // 3. Await the retry with your policy, a sleep function, and your async function. retry(Retries(3), tokio::time::sleep, make_request).await } ```

Tracing

Add the tracing feature and you can use the Traced RetryPolicy to automatically log your retries

Tokio

Add the tokio feature and you can use the convenience tokio retry methods to skip specifying [tokio::time::sleep].

You can also use the [tokio::RetryFutureExt] trait to support calling retry directly on async functions.

```rust

[tokio::main]

async fn main() -> Result<(), &'static str> { make_request.retry(Retries(3)).await } ```

retry-policies

This crate has first class support for the retry-policies crate

```rust use futuresretrypolicies::{retry, retrypolicies::{ShouldRetry, RetryPolicies}}; use retrypolicies::policies::ExponentialBackoff;

enum Error { Retry, DoNotRetry } impl ShouldRetry for Error { fn shouldretry(&self, _: u32) -> bool { matches!(self, Error::Retry) } } async fn makerequest() -> Result<(), Error> { // make a request # static COUNT: std::sync::atomic::AtomicUsize = std::sync::atomic::AtomicUsize::new(0); # if COUNT.fetch_add(1, std::sync::atomic::Ordering::SeqCst) < 2 { Err(Error::Retry) } else { Ok(()) } }

[tokio::main]

async fn main() -> Result<(), Error> { let backoff = ExponentialBackoff::builder().buildwithmaxretries(3); let policy = RetryPolicies::new(backoff); retry(policy, tokio::time::sleep, makerequest).await } ```