PollySignalR

Polly v8 reconnect policy for ASP.NET Core SignalR.
Drop-in replacement for WithAutomaticReconnect(TimeSpan[]) with full Polly v8 exponential back-off, jitter, configurable max retries, and max delay. Also provides StartWithResilienceAsync for resilient initial connections.

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Why PollySignalR?

SignalR's built-in reconnect is limited to a fixed array of delays:

Feature	WithAutomaticReconnect(TimeSpan[])	PollySignalR
Exponential back-off	❌ manual	✅ automatic
Jitter (reconnect storm prevention)	❌	✅
Configurable max retries	❌ array length	✅
Max delay cap	❌ last array element	✅
Linear back-off option	❌	✅
Infinite retries	❌	✅
Polly v8 pipeline for initial connect	❌	✅
Single line of config	❌	✅

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Installation

dotnet add package PollySignalR

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Quick Start

var connection = new HubConnectionBuilder()
    .WithUrl("https://example.com/hub")
    .WithPollyReconnect()   // exponential back-off, infinite retries, up to 60 s
    .Build();

---

Configuration

var connection = new HubConnectionBuilder()
    .WithUrl("https://example.com/hub")
    .WithPollyReconnect(options =>
    {
        options.MaxRetries   = 10;                          // null = infinite (default)
        options.BaseDelay    = TimeSpan.FromSeconds(1);     // default: 1 s
        options.MaxDelay     = TimeSpan.FromSeconds(60);    // default: 60 s
        options.JitterFactor = 0.5;                         // ±50% noise (default)
        options.BackoffType  = DelayBackoffType.Exponential; // or Linear
    })
    .Build();

How delays are computed

delay = clamp(BaseDelay × 2^attempt, 0, MaxDelay)
      + random(−JitterFactor × BaseDelay, +JitterFactor × BaseDelay)

Attempt	BaseDelay=1s, MaxDelay=60s
0	~1 s
1	~2 s
2	~4 s
3	~8 s
4	~16 s
5	~32 s
6+	~60 s (capped)

---

Resilient initial connection

Use StartWithResilienceAsync to apply a full Polly v8 pipeline to the first connect attempt (before automatic reconnect takes over):

var pipeline = new ResiliencePipelineBuilder()
    .AddRetry(new RetryStrategyOptions
    {
        ShouldHandle  = new PredicateBuilder().Handle<Exception>(),
        MaxRetryAttempts = 5,
        BackoffType   = DelayBackoffType.Exponential,
        Delay         = TimeSpan.FromSeconds(1),
        UseJitter     = true,
    })
    .AddTimeout(new TimeoutStrategyOptions { Timeout = TimeSpan.FromSeconds(30) })
    .Build();

await connection.StartWithResilienceAsync(pipeline);

---

Blazor WebAssembly

// Program.cs
builder.Services.AddSingleton(sp =>
    new HubConnectionBuilder()
        .WithUrl(builder.HostEnvironment.BaseAddress + "chathub")
        .WithPollyReconnect(o =>
        {
            o.BaseDelay  = TimeSpan.FromSeconds(2);
            o.MaxDelay   = TimeSpan.FromSeconds(120);
            o.MaxRetries = null; // never give up
        })
        .Build());

---

Related Packages

Package	Downloads	Description
PollyHealthChecks		ASP.NET Core health checks for Polly v8 circuit breakers — expose circuit-breaker state (Closed, HalfOpen, Open, Isolated) as /health endpoint responses
PollyBackoff		Backoff delay strategies for Polly v8 resilience pipelines
PollyGrpc		Polly v8 resilience interceptor for gRPC
PollyEFCore		Polly v8 resilience pipelines for Entity Framework Core — wrap every EF Core query and SaveChanges with retry, timeout and circuit-breaker via a single AddPollyResilience() call
PollyMailKit		Polly v8 resilience pipelines for MailKit — retry, timeout, and circuit-breaker for SmtpClient.SendAsync and any MailKit SMTP operation
PollyMassTransit		Polly v8 resilience pipelines for MassTransit — retry, timeout, and circuit-breaker for IBus.Publish and ISendEndpointProvider.Send
PollyOpenAI		Polly v8 resilience for OpenAI and Azure OpenAI API calls
PollyAzureEventHub		Polly v8 resilience pipelines for Azure Event Hubs — retry, timeout, and circuit-breaker for EventHubProducerClient and EventHubConsumerClient
PollyElasticsearch		Polly v8 resilience pipelines for Elastic.Clients.Elasticsearch 8+ — retry, timeout, and circuit-breaker for any Elasticsearch operation, plus a built-in ElasticTransientErrors predicate covering rate limiting (429), service unavailability (503), gateway timeouts (504), and connection failures
PollyHangfire		Polly v8 resilience pipelines for Hangfire — retry, timeout, and circuit-breaker for IBackgroundJobClient.Enqueue and Schedule
PollySendGrid		Polly v8 resilience pipelines for SendGrid — retry, timeout, and circuit-breaker for ISendGridClient.SendEmailAsync
PollyMediatR		Polly v8 resilience pipelines for MediatR — add retry, timeout, circuit-breaker, rate-limiting, hedging, and chaos engineering to any MediatR request handler with a single line of DI registration
PollyAzureKeyVault		Polly v8 resilience pipelines for Azure Key Vault — retry, timeout, and circuit-breaker for SecretClient, KeyClient, and CertificateClient
PollyAzureQueueStorage		Polly v8 resilience pipelines for Azure Queue Storage — retry, timeout, and circuit-breaker for Azure.Storage.Queues QueueClient
PollyRedis		Polly v8 resilience for StackExchange.Redis
PollyAzureServiceBus		Polly v8 resilience for Azure Service Bus — retry, circuit breaker, and timeout for sending and receiving messages
PollyKafka		Polly v8 resilience for Confluent.Kafka — retry, circuit breaker, and timeout for producers and consumers
PollyAzureTableStorage		Polly v8 resilience pipelines for Azure Table Storage — retry, timeout, and circuit-breaker for Azure.Data.Tables TableClient
PollyChaos		Chaos engineering and fault-injection resilience strategies for Polly v8 pipelines

💼 Need .NET consulting?

The author of this package is available for consulting on Polly v8 resilience, Azure cloud architecture, and clean .NET design.

→ solidqualitysolutions.com · LinkedIn

License

MIT