PollyBulkhead 1.0.0

Polly.Contrib.Bulkhead

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

Bulkhead isolation strategy for Polly v8 resilience pipelines. Limits concurrent executions and queued actions, rejecting excess calls with BulkheadRejectedException.

Polly v8 replaced the v7 BulkheadPolicy with the more general RateLimiter strategy. This package restores the familiar bulkhead semantics — explicit max concurrency and max queue depth — as a first-class Polly v8 resilience strategy.

Install

dotnet add package Polly.Contrib.Bulkhead

Usage

Simple concurrency limit

using Polly.Contrib.Bulkhead;

var pipeline = new ResiliencePipelineBuilder()
    .AddBulkhead(maxConcurrency: 10)
    .Build();

await pipeline.ExecuteAsync(async ct => await CallDownstreamAsync(ct), cancellationToken);

With a queue

var pipeline = new ResiliencePipelineBuilder()
    .AddBulkhead(maxConcurrency: 10, maxQueuedActions: 20)
    .Build();

Calls beyond the 10 concurrent slots queue up. If the queue also fills (>20 waiting), further calls throw BulkheadRejectedException.

Full options

var pipeline = new ResiliencePipelineBuilder()
    .AddBulkhead(new BulkheadStrategyOptions
    {
        MaxConcurrency = 10,
        MaxQueuedActions = 20,
        OnBulkheadRejected = args =>
        {
            logger.LogWarning("Bulkhead rejected call for {Operation}", args.Context.OperationKey);
            return ValueTask.CompletedTask;
        },
    })
    .Build();

Generic pipeline

var pipeline = new ResiliencePipelineBuilder<HttpResponseMessage>()
    .AddBulkhead<HttpResponseMessage>(maxConcurrency: 5)
    .AddRetry(...)
    .Build();

Behaviour

Composition

Place bulkhead before retry so rejected calls don't get retried:

var pipeline = new ResiliencePipelineBuilder()
    .AddBulkhead(maxConcurrency: 10)  // 1. limit concurrency first
    .AddRetry(...)                     // 2. retry transient failures
    .AddCircuitBreaker(...)            // 3. protect downstream
    .Build();

Support

If Polly.Contrib.Bulkhead helps protect your services, consider supporting the project:

💼 Need .NET resilience help? Visit solidqualitysolutions.com for consulting and architecture services.

License

MIT