Crate tower_retry_plus 

Enhanced retry middleware for Tower services.

This crate provides advanced retry functionality beyond Tower’s built-in retry, with flexible backoff strategies, retry predicates, and comprehensive event system.

Features

• IntervalFunction abstraction: Pluggable backoff strategies
  • Fixed interval
  • Exponential backoff with configurable multiplier
  • Exponential random backoff with randomization factor
  • Custom function-based backoff
• Retry predicates: Control which errors should be retried
• Event system: Observability through retry events
• Flexible configuration: Builder API with sensible defaults

Examples

use tower_retry_plus::RetryConfig;
use tower::ServiceBuilder;
use std::time::Duration;

// Create retry configuration with exponential backoff
let retry_config: RetryConfig<MyError> = RetryConfig::builder()
    .max_attempts(5)
    .exponential_backoff(Duration::from_millis(100))
    .on_retry(|attempt, delay| {
        println!("Retry attempt {} after {:?}", attempt, delay);
    })
    .build();

// Apply to a service
let service = ServiceBuilder::new()
    .layer(retry_config.layer())
    .service(tower::service_fn(|req: String| async move {
        Ok::<_, MyError>(format!("Response: {}", req))
    }));

Structs

ExponentialBackoff

Exponential backoff with configurable multiplier.

ExponentialRandomBackoff

Exponential backoff with randomization to prevent thundering herd.

FixedInterval

Fixed interval backoff - returns the same duration for every retry.

FnInterval

Function-based interval implementation.

Retry

A Tower Service that retries failed requests.

RetryConfig

Configuration for the retry middleware.

RetryConfigBuilder

Builder for RetryConfig.

RetryLayer

A Tower Layer that applies retry logic to a service.

RetryPolicy

Policy for retry behavior.

Enums

RetryEvent

Events emitted by the retry middleware.

Traits

IntervalFunction

Abstraction for computing retry intervals.

Type Aliases

RetryPredicate

Determines whether an error should be retried.