ZeroAlloc.Resilience

Source-generated, zero-allocation resilience policies for .NET.

Add [Retry], [Timeout], [RateLimit], and [CircuitBreaker] to an interface; the generator emits a proxy composing all policies in declaration order with no heap allocation on the happy path.

Quick example

[Retry(MaxAttempts = 3, BackoffMs = 200, Jitter = true)]
[Timeout(Ms = 5_000)]
[CircuitBreaker(MaxFailures = 5, ResetMs = 1_000, HalfOpenProbes = 1, Fallback = nameof(FetchFallback))]
public interface IExternalService
{
    ValueTask<string> FetchAsync(string id, CancellationToken ct);
    ValueTask<string> FetchFallback(string id, CancellationToken ct);
}

// Register — one line
services.AddExternalServiceResilience<ExternalServiceImpl>();

// Inject IExternalService — all policies are wired automatically

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Contents

Page	Description
Getting Started	Install, annotate an interface, register with DI
Attributes	[Retry], [Timeout], [RateLimit], [CircuitBreaker] reference
Source Generator	What the generator emits — annotated proxy example
Performance	Benchmark results and allocation profile

Core Concepts

Page	Description
Retry	Exponential backoff, jitter, per-attempt timeout, exhaustion behaviour
Timeout	Total timeout vs. per-attempt timeout, CTS lifecycle
Rate Limit	Token bucket, lock-free acquire, Shared vs Instance scope
Circuit Breaker	State machine, failure tracking, half-open probing, fallback
Execution Order	How policies compose: RateLimit → CB → Timeout → Retry

Guides

Page	Description
Fallback	Declare and implement circuit-breaker fallback methods
Method-Level Overrides	Per-method policy configuration
Result Return Types	Non-throwing failure path with Result<T>
DI Registration	Generated extension method, overrides, manual construction

Diagnostics

ID	Severity	Description
ZR0001	Error	Fallback method not found or signature mismatch
ZR0002	Warning	Timeout configured but method has no CancellationToken