PollyMongo 1.0.1

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.

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

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
PollyEFCore		Polly v8 resilience for EF Core queries and SaveChanges
PollyCosmosDb		Polly v8 resilience for Azure Cosmos DB with CosmosTransientErrors predicate
PollyDapper		Polly v8 resilience for Dapper queries and commands
PollySqlClient		Polly v8 resilience for SQL Server and Azure SQL with SqlServerTransientErrors predicate
PollyMediatR		Polly v8 resilience pipelines for MediatR
PollyRedis		Polly v8 resilience for StackExchange.Redis
PollyHealthChecks		ASP.NET Core health checks for Polly v8 circuit breakers
PollyOpenAI		Polly v8 resilience for OpenAI and Azure OpenAI
PollyElasticsearch	Polly v8 for Elastic.Clients.Elasticsearch
PollyAzureKeyVault	Polly v8 for Azure Key Vault
PollySendGrid	Polly v8 for SendGrid
PollyMassTransit	Polly v8 for MassTransit
PollyAzureTableStorage	Polly v8 for Azure Table Storage
PollyMailKit	MailKit SMTP email client
PollyAzureQueueStorage	Azure Queue Storage QueueClient
PollyHangfire	Hangfire IBackgroundJobClient
PollyBackoff		Jitter, linear & custom backoff for Polly v8 retry
PollyChaos		Fault & latency injection (Simmy for Polly v8)
PollyAzureEventHub	Polly v8 for Azure Event Hubs
PollyAzureServiceBus		Polly v8 resilience for Azure Service Bus

💼 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