PollyAzureEventHub

Polly v8 resilience for Azure.Messaging.EventHubs — add retry, timeout, and circuit-breaker to any Event Hubs producer operation in two lines.

var producer = new EventHubProducerClient(connectionString, "my-hub");

var resilient = producer.WithPolly(pipeline => pipeline
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromSeconds(2),
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true,
        ShouldHandle = EventHubsTransientErrors.IsTransient,
    })
    .AddTimeout(TimeSpan.FromSeconds(30)));

using var batch = await resilient.CreateBatchAsync();
batch.TryAdd(new EventData("hello"));
await resilient.SendAsync(batch);

Why PollyAzureEventHub?

Azure Event Hubs is a mission-critical ingestion pipeline — dropped events mean lost data. EventHubsException.IsTransient tells you exactly which errors are safe to retry; this library wires that directly into Polly v8:

Problem	Solution
EventHubsException where IsTransient = true (throttling, service busy, connection dropped)	Caught by EventHubsTransientErrors.IsTransient
TimeoutException — service took too long to respond	Caught by EventHubsTransientErrors.IsTransient
TaskCanceledException — network timeout during transit	Caught by EventHubsTransientErrors.IsTransient
Non-retriable errors (bad request, auth failure)	Not retried — IsTransient = false is respected
Cascading failures during an outage	Wrap with AddCircuitBreaker

Installation

dotnet add package PollyAzureEventHub
dotnet add package Polly.Core

Quick-start

1. Manual wiring

using Azure.Messaging.EventHubs;
using Azure.Messaging.EventHubs.Producer;
using Polly;
using Polly.Retry;

var producer = new EventHubProducerClient(connectionString, "telemetry");

var resilient = producer.WithPolly(p => p
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromSeconds(2),
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true,
        ShouldHandle = EventHubsTransientErrors.IsTransient,
    }));

// Send a batch
using var batch = await resilient.CreateBatchAsync();
foreach (var reading in sensorReadings)
    batch.TryAdd(new EventData(JsonSerializer.SerializeToUtf8Bytes(reading)));

await resilient.SendAsync(batch);

2. Dependency injection

// Program.cs / Startup.cs
builder.Services.AddPollyAzureEventHub(
    connectionString,
    "telemetry",
    pipeline => pipeline
        .AddRetry(new RetryStrategyOptions
        {
            MaxRetryAttempts = 3,
            Delay = TimeSpan.FromSeconds(2),
            BackoffType = DelayBackoffType.Exponential,
            UseJitter = true,
            ShouldHandle = EventHubsTransientErrors.IsTransient,
        })
        .AddTimeout(TimeSpan.FromSeconds(30)));

// Inject ResilientEventHubProducerClient into your services
public class TelemetryIngester(ResilientEventHubProducerClient producer)
{
    public async Task SendAsync(IEnumerable<Reading> readings, CancellationToken ct)
    {
        using var batch = await producer.CreateBatchAsync(ct);
        foreach (var r in readings)
            batch.TryAdd(new EventData(JsonSerializer.SerializeToUtf8Bytes(r)));
        await producer.SendAsync(batch, ct);
    }
}

3. Bring your own client (DI overload)

builder.Services.AddSingleton(new EventHubProducerClient(
    fullyQualifiedNamespace,
    "telemetry",
    new DefaultAzureCredential()));

builder.Services.AddPollyAzureEventHub(pipeline => pipeline
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 5,
        ShouldHandle = EventHubsTransientErrors.IsTransient,
    }));

Transient error reference

// Use in any Polly strategy:
ShouldHandle = EventHubsTransientErrors.IsTransient

Condition	Why it's transient
EventHubsException (IsTransient = true)	Service throttling, quota exceeded, brief outage — SDK-designated as safe to retry
EventHubsException (IsTransient = false)	Auth failure, bad request — not retried
TimeoutException	Operation timed out waiting for service response
TaskCanceledException	Network-level cancellation or timeout

Key differentiator: EventHubsException.IsTransient is set by the Azure SDK team — this library exposes it directly as a Polly predicate, so your retry logic is always in sync with the SDK's own classification.

Advanced pipelines

Full production pipeline with observability

producer.WithPolly(p => p
    .AddTimeout(TimeSpan.FromSeconds(60))
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 5,
        Delay = TimeSpan.FromSeconds(1),
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true,
        ShouldHandle = EventHubsTransientErrors.IsTransient,
        OnRetry = args =>
        {
            logger.LogWarning("Event Hubs retry {Attempt} after {Delay}ms — {Exception}",
                args.AttemptNumber, args.RetryDelay.TotalMilliseconds, args.Outcome.Exception?.Message);
            return ValueTask.CompletedTask;
        },
    })
    .AddCircuitBreaker(new CircuitBreakerStrategyOptions
    {
        FailureRatio = 0.5,
        SamplingDuration = TimeSpan.FromSeconds(30),
        MinimumThroughput = 10,
        BreakDuration = TimeSpan.FromSeconds(30),
        ShouldHandle = EventHubsTransientErrors.IsTransient,
    }));

Sending with partition key

var options = new SendEventOptions { PartitionKey = deviceId };
await resilient.SendAsync(events, options, cancellationToken);

Arbitrary operations via ExecuteAsync

var partitionProps = await resilient.ExecuteAsync(
    (c, ct) => c.GetPartitionPropertiesAsync("0", ct));

API reference

ResilientEventHubProducerClient

Member	Description
Inner	The underlying EventHubProducerClient
CreateBatchAsync(ct)	Creates a batch through the pipeline
CreateBatchAsync(options, ct)	Creates a batch with options through the pipeline
SendAsync(batch, ct)	Sends a batch through the pipeline
SendAsync(events, ct)	Sends a collection of events through the pipeline
SendAsync(events, options, ct)	Sends events with partition options through the pipeline
ExecuteAsync<T>(operation, ct)	Runs any EventHubProducerClient operation through the pipeline

EventHubsTransientErrors

Member	Description
IsTransient	PredicateBuilder for transient EventHubsException, TimeoutException, TaskCanceledException

Extension methods

Method	Description
client.WithPolly(pipeline)	Wraps an EventHubProducerClient with a pre-built ResiliencePipeline
client.WithPolly(configure)	Builds a pipeline inline and wraps the client

DI extensions

Method	Description
services.AddPollyAzureEventHub(configure)	Registers ResiliencePipeline + ResilientEventHubProducerClient (requires EventHubProducerClient already in DI)
services.AddPollyAzureEventHub(connectionString, hubName, configure)	Registers EventHubProducerClient, pipeline, and resilient client

Target frameworks

Framework	Supported
.NET 6	✅
.NET 8	✅
.NET 9	✅

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
PollyRabbitMQ		Polly v8 resilience for RabbitMQ.Client v7+ — retry, circuit-breaker, and timeout for IChannel operations, with built-in RabbitMqTransientErrors predicate covering AlreadyClosedException, BrokerUnreachableException, OperationInterruptedException, and ConnectFailureException
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
PollyNpgsql		Polly v8 resilience pipelines for Npgsql (PostgreSQL) — retry, timeout, and circuit-breaker for NpgsqlConnection queries and commands, plus a built-in PostgresTransientErrors predicate covering all common PostgreSQL transient SQLSTATE codes
PollyOpenAI		Polly v8 resilience for OpenAI and Azure OpenAI API calls
PollySignalR		Polly v8 reconnect policy for SignalR
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
PollyCosmosDb		Polly v8 resilience pipelines for Azure Cosmos DB — retry, timeout, and circuit-breaker for Container operations, plus a built-in CosmosTransientErrors predicate covering rate limiting (429), timeouts (408), partition failovers (410), and service unavailability (503)
PollySendGrid		Polly v8 resilience pipelines for SendGrid — retry, timeout, and circuit-breaker for ISendGridClient.SendEmailAsync
PollyMongo		Polly v8 resilience pipelines for MongoDB.Driver — wrap Find, InsertOne, UpdateOne, DeleteOne and other IMongoCollection calls with retry, timeout, circuit-breaker, and more using a single ResilientMongoCollection decorator
PollyDapper		Polly v8 resilience pipelines for Dapper — wrap QueryAsync, ExecuteAsync, and other Dapper calls with retry, timeout, circuit-breaker, and more using a single ResilientDbConnection decorator
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
PollySqlClient		Polly v8 resilience pipelines for Microsoft.Data.SqlClient (SQL Server and Azure SQL) — retry, timeout, and circuit-breaker for SqlConnection queries and commands, plus a built-in SqlServerTransientErrors predicate covering all common SQL Server and Azure SQL transient error numbers
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
PollyAzureBlob		Polly v8 resilience pipelines for Azure Blob Storage — wrap BlobClient and BlobContainerClient operations with retry, timeout, circuit-breaker, and more using ResilientBlobClient and ResilientBlobContainerClient decorators
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

💼 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 © Justin Bannister