PollyBackoff 1.0.4

PollyBackoff

<img src="icon.png" width="100" align="right" />

Backoff delay strategies for Polly v8 resilience pipelines.

Polly.Contrib.WaitAndRetry was built for Polly v7's WaitAndRetry() API. Polly v8 uses a DelayGenerator delegate — this package provides the same beloved strategies in the new API.

Install

dotnet add package PollyBackoff

Usage

Fluent extension on RetryStrategyOptions

using PollyBackoff;

var pipeline = new ResiliencePipelineBuilder<HttpResponseMessage>()
    .AddRetry(new RetryStrategyOptions<HttpResponseMessage>
    {
        MaxRetryAttempts = 5,
        ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
            .Handle<HttpRequestException>()
            .HandleResult(r => !r.IsSuccessStatusCode)
    }
    .UseDecorrelatedJitter(baseDelay: TimeSpan.FromMilliseconds(100)))
    .Build();

Direct Backoff factory

var backoff = Backoff.DecorrelatedJitter(baseDelay: TimeSpan.FromMilliseconds(100));

var pipeline = new ResiliencePipelineBuilder()
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 5,
        DelayGenerator = args => new ValueTask<TimeSpan?>(backoff(args.AttemptNumber))
    })
    .Build();

Strategies

Decorrelated Jitter (recommended)

Based on the algorithm from Marc Brooker's blog and AWS guidance. Each delay is randomly chosen from [baseDelay, previous × factor], capped at maxDelay. Avoids retry storms by spreading attempts across time.

options.UseDecorrelatedJitter(
    baseDelay: TimeSpan.FromMilliseconds(100),
    factor: 3.0,              // default
    maxDelay: TimeSpan.FromSeconds(30));  // default

Exponential Backoff

delay = min(maxDelay, baseDelay × factor^attempt), with optional full jitter.

options.UseExponentialBackoff(
    baseDelay: TimeSpan.FromMilliseconds(100),
    factor: 2.0,              // default
    maxDelay: TimeSpan.FromSeconds(30),
    addJitter: true);

Linear Backoff

delay = baseDelay + increment × attempt, capped at maxDelay.

options.UseLinearBackoff(
    baseDelay: TimeSpan.FromMilliseconds(100),
    increment: TimeSpan.FromMilliseconds(100),  // defaults to baseDelay
    maxDelay: TimeSpan.FromSeconds(10),
    addJitter: false);

Constant Backoff

Fixed delay every attempt, with optional ±jitter.

options.UseConstantBackoff(
    delay: TimeSpan.FromSeconds(1),
    addJitter: true,
    jitterFactor: 0.1);  // ±10%

Composing with existing DelayGenerator

Each strategy also exposes a Func<int, TimeSpan> you can use directly:

var backoff = Backoff.ExponentialBackoff(TimeSpan.FromMilliseconds(100), addJitter: true);

// attempt 0 → ~100ms, attempt 1 → ~200ms, attempt 2 → ~400ms (with jitter)
TimeSpan delay = backoff(attemptNumber);

License

MIT