Verbara.Sdk.Resilience 2.2.1

Verbara.Sdk.Resilience

Composable resilience primitives for .NET. AOT-safe, zero reflection, TimeProvider-based for testability. No Polly dependency. MIT licensed.

What it does

• Circuit breaker — per-key CircuitBreakerState with classic closed → open → half-open → closed cycle. Thread-safe via Interlocked/Volatile; no locks.
• Retry with exponential backoff — configurable maxAttempts (capped at 10) and baseDelay with ±20% deterministic jitter.
• Per-attempt timeout — wraps action in linked CancellationTokenSource that honours both caller token and timeout.
• Fluent builder — compose any subset of the three primitives via ResiliencePolicyBuilder and call Build().
• First-class diagnostics via System.Diagnostics.Metrics (meter name Verbara.Sdk.Resilience): retry.attempts, circuit.opened, circuit.closed, timeout.fired, circuit.state observable gauge.

No external runtime dependencies beyond Microsoft.Extensions.* abstractions. Trim-safe.

Install

dotnet add package Verbara.Sdk.Resilience

Quick start

using Verbara.Sdk.Resilience;
using Verbara.Sdk.Resilience.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;

// 1) Register a default policy (or a no-op if configure is null).
var services = new ServiceCollection();
services.AddAsteriskResilience(b => b
    .WithCircuitBreaker(threshold: 5, openDuration: TimeSpan.FromSeconds(30))
    .WithRetry(maxAttempts: 3, baseDelay: TimeSpan.FromMilliseconds(100))
    .WithTimeout(TimeSpan.FromSeconds(5)));

// 2) Resolve + execute.
var provider = services.BuildServiceProvider();
var policy = provider.GetRequiredService<ResiliencePolicy>();

var result = await policy.ExecuteAsync(
    key: "payment-gateway",
    action: async ct =>
    {
        // Work that may throw (network call, DB write, external API, etc.).
        return await CallPaymentGatewayAsync(ct);
    },
    ct: CancellationToken.None);

Directly (without DI)

var policy = new ResiliencePolicyBuilder()
    .WithRetry(3, TimeSpan.FromMilliseconds(100))
    .WithTimeout(TimeSpan.FromSeconds(5))
    .Build();

await policy.ExecuteAsync("key", async ct => { /* work */ return 42; }, ct: default);

Observability

Meter name: Verbara.Sdk.Resilience. Enrol in OpenTelemetry:

builder.Services.AddOpenTelemetry()
    .WithMetrics(m => m.AddMeter("Verbara.Sdk.Resilience"));

Or transparently via AddAsteriskOpenTelemetry().WithAllSources().

Instruments emitted:

Testing

TimeProvider.System is the default clock. Inject FakeTimeProvider (Microsoft.Extensions.TimeProvider.Testing) via WithTimeProvider(fakeTimeProvider) for deterministic backoff delays and circuit open-duration testing.

License

MIT. Part of the Verbara.Sdk project.