> For the complete documentation index, see [llms.txt](https://brightercommand.gitbook.io/paramore-brighter-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://brightercommand.gitbook.io/paramore-brighter-documentation/outbox-and-inbox/distributedlock/mongodbdistributedlock.md).

# MongoDB Distributed Lock

The MongoDB locking provider implements Brighter's [distributed lock](/paramore-brighter-documentation/outbox-and-inbox/distributedlock.md) by writing lock documents to a MongoDB collection, so a single [Outbox Sweeper](/paramore-brighter-documentation/outbox-and-inbox/brighteroutboxsupport.md#implicit-clear) and Archiver run when you scale out. It pairs naturally with the [MongoDB Outbox](/paramore-brighter-documentation/outbox-and-inbox/mongodboutbox.md).

## Package

* **Paramore.Brighter.Locking.MongoDb**

The provider stores its locks in a collection that you name through the MongoDB configuration — see [Provisioning](#provisioning).

## Configuration

The MongoDB provider is configured through an `IAmAMongoDbConfiguration`, the same configuration type used by the MongoDB Outbox. Set its `Locking` property to a `MongoDbCollectionConfiguration` that names the lock collection and, optionally, a time-to-live for lock documents:

```csharp
var configuration = new MongoDbConfiguration(
    connectionString: "mongodb://localhost:27017",
    databaseName: "orders")
{
    Locking = new MongoDbCollectionConfiguration
    {
        Name = "brighter_locks",
        TimeToLive = TimeSpan.FromMinutes(1)
    }
};

var lockingProvider = new MongoDbLockingProvider(configuration);
```

`MongoDbLockingProvider` also has a constructor that accepts an `IAmAMongoDbConnectionProvider` alongside the configuration if you want to share a connection provider.

| Setting (on `Locking`) | Type        | Description                                                              |
| ---------------------- | ----------- | ------------------------------------------------------------------------ |
| `Name`                 | `string`    | The collection that holds the lock documents.                            |
| `TimeToLive`           | `TimeSpan?` | Optional expiry for lock documents, applied through a MongoDB TTL index. |

## Example

```csharp
var configuration = new MongoDbConfiguration("mongodb://localhost:27017", "orders")
{
    Locking = new MongoDbCollectionConfiguration { Name = "brighter_locks", TimeToLive = TimeSpan.FromMinutes(1) }
};

services
    .AddBrighter()
    .AddProducers(opt =>
    {
        opt.Outbox = /* your MongoDB Outbox */;
        // ... connection/transaction providers for your Outbox ...

        opt.DistributedLock = new MongoDbLockingProvider(configuration);
    })
    .UseOutboxSweeper(opt => { opt.BatchSize = 10; });
```

## Provisioning

The provider writes lock documents to the collection named by `Locking.Name` and relies on a unique index on the resource so only one instance can hold a given lock. If you set `TimeToLive`, a TTL index expires stale lock documents automatically, which protects you if an instance crashes before releasing its lock. Ensure the application's MongoDB user can create the collection and its indexes, or create them ahead of time.

## Notes

* Set `TimeToLive` longer than a typical Sweeper or Archiver batch so a lock is not expired mid-run. See [Lease Expiry vs Manual Release](/paramore-brighter-documentation/outbox-and-inbox/distributedlock.md#lease-expiry-vs-manual-release).
* Point the provider at the same MongoDB database as your Outbox so the Sweeper, Archiver, and lock share infrastructure.

## Further Reading

* [Distributed Lock](/paramore-brighter-documentation/outbox-and-inbox/distributedlock.md) — concepts and the full provider list
* [MongoDB Outbox](/paramore-brighter-documentation/outbox-and-inbox/mongodboutbox.md) — the matching Outbox
* [Outbox Support](/paramore-brighter-documentation/outbox-and-inbox/brighteroutboxsupport.md) — the Sweeper and Archiver


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://brightercommand.gitbook.io/paramore-brighter-documentation/outbox-and-inbox/distributedlock/mongodbdistributedlock.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.