PollyMongo

Polly v8 resilience pipelines for MongoDB.Driver — wrap Find, InsertOne, UpdateOne, DeleteOne, and other IMongoCollection<T> calls with retry, timeout, circuit-breaker, and more using a single ResilientMongoCollection<T> decorator. Zero changes to your queries.

var resilient = collection.WithPolly(pipeline =>
    pipeline
        .AddRetry(new RetryStrategyOptions
        {
            MaxRetryAttempts = 3,
            Delay = TimeSpan.FromMilliseconds(200),
            ShouldHandle = new PredicateBuilder().Handle<MongoException>(),
        })
        .AddTimeout(TimeSpan.FromSeconds(5)));

var orders = await resilient.FindAsync(Builders<Order>.Filter.Eq(o => o.CustomerId, id));

Every MongoDB operation is now automatically wrapped with retry + timeout — zero changes to existing queries.

---

Why PollyMongo?

MongoDB.Driver has no built-in retry or timeout interception beyond connection-level settings. PollyMongo adds operation-level resilience cleanly.

Without PollyMongo	With PollyMongo
Write try/catch + retry loops around every query	One WithPolly(...) call
Manually cancel long-running operations	Timeout managed by the pipeline
Duplicate retry logic across repositories	Single pipeline applied everywhere
Must touch every operation to add resilience	Zero changes to existing queries

---

Installation

dotnet add package PollyMongo

Targets net6.0, net8.0, and net9.0.

Dependencies: Polly.Core 8.*, MongoDB.Driver 3.*, Microsoft.Extensions.DependencyInjection.Abstractions 8.*

---

Quick start

1. Inline pipeline (ad-hoc usage)

using PollyMongo;

var resilient = collection.WithPolly(pipeline =>
    pipeline.AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromMilliseconds(200),
        BackoffType = DelayBackoffType.Exponential,
        ShouldHandle = new PredicateBuilder().Handle<MongoException>(),
    }));

var users = await resilient.FindAsync(Builders<User>.Filter.Empty);

2. Pre-built pipeline

var pipeline = new ResiliencePipelineBuilder()
    .AddRetry(new RetryStrategyOptions { MaxRetryAttempts = 3 })
    .AddTimeout(TimeSpan.FromSeconds(10))
    .Build();

var resilient = collection.WithPolly(pipeline);
var count = await resilient.CountDocumentsAsync(Builders<Order>.Filter.Empty);

3. Dependency injection

// Program.cs
builder.Services.AddPollyMongo(pipeline =>
    pipeline
        .AddRetry(new RetryStrategyOptions { MaxRetryAttempts = 3 })
        .AddTimeout(TimeSpan.FromSeconds(5)));

// Repository
public class OrderRepository(IMongoCollection<Order> collection, ResiliencePipeline pipeline)
{
    public Task<List<Order>> GetAllAsync() =>
        collection.WithPolly(pipeline).FindAsync(Builders<Order>.Filter.Empty);

    public Task InsertAsync(Order order) =>
        collection.WithPolly(pipeline).InsertOneAsync(order);
}

---

Supported operations

Method	Description
FindAsync<T>	Returns List<T> matching the filter
FindOneAsync<T>	First matching document or default
InsertOneAsync	Insert a single document
InsertManyAsync	Insert multiple documents
UpdateOneAsync	Update first matching document
UpdateManyAsync	Update all matching documents
ReplaceOneAsync	Replace first matching document
DeleteOneAsync	Delete first matching document
DeleteManyAsync	Delete all matching documents
CountDocumentsAsync	Count matching documents
FindOneAndUpdateAsync	Atomic find + update
FindOneAndDeleteAsync	Atomic find + delete
FindOneAndReplaceAsync	Atomic find + replace

---

Pipeline order

Polly strategies are applied outer-to-inner (left-to-right). The recommended order is:

[Timeout] → [Retry] → [Circuit Breaker] → [MongoDB]

pipeline
    .AddTimeout(TimeSpan.FromSeconds(10))    // 1. Overall deadline
    .AddRetry(retryOptions)                  // 2. Retry on failure
    .AddCircuitBreaker(cbOptions)            // 3. Open circuit if overloaded

---

ASP.NET Core example

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSingleton<IMongoClient>(_ =>
    new MongoClient(builder.Configuration.GetConnectionString("Mongo")));

builder.Services.AddScoped(sp =>
    sp.GetRequiredService<IMongoClient>()
      .GetDatabase("mydb")
      .GetCollection<Order>("orders"));

builder.Services.AddPollyMongo(pipeline =>
    pipeline
        .AddRetry(new RetryStrategyOptions
        {
            MaxRetryAttempts = 3,
            Delay = TimeSpan.FromMilliseconds(100),
            BackoffType = DelayBackoffType.Exponential,
            ShouldHandle = new PredicateBuilder()
                .Handle<MongoConnectionException>()
                .Handle<MongoConnectionPoolWaitQueueFullException>()
                .Handle<MongoExecutionTimeoutException>(),
        })
        .AddTimeout(TimeSpan.FromSeconds(30))
        .AddCircuitBreaker(new CircuitBreakerStrategyOptions
        {
            FailureRatio = 0.5,
            MinimumThroughput = 10,
            SamplingDuration = TimeSpan.FromSeconds(30),
            BreakDuration = TimeSpan.FromSeconds(15),
        }));

---

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
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
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
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
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