MongoDB

MongoDB is a cross-platform, document-oriented database program. Classified as a NoSQL database, MongoDB uses JSON-like documents with dynamic schema.

CAP has supported MongoDB since version 2.3. MongoDB supports ACID transactions starting from version 4.0, so CAP requires MongoDB 4.0 or higher. Additionally, MongoDB must be deployed as a cluster because ACID transactions require a replica set.

For a quick development of the MongoDB 4.0+ cluster for the development environment, you can refer to this article.

Configuration

To use MongoDB storage, you need to install the following package from NuGet:

PM> Install-Package DotNetCore.CAP.MongoDB

Next, add configuration items to the ConfigureServices method of Startup.cs.

public void ConfigureServices(IServiceCollection services)
{
    // ...

    services.AddCap(x =>
    {
        x.UseMongoDB(opt=>{
            //MongoDBOptions
        });
        // x.UseXXX ...
    });
}

MongoDB Options

NAME	DESCRIPTION	TYPE	DEFAULT
DatabaseName	Database name	string	cap
DatabaseConnection	Database connection string	string	mongodb://localhost:27017
ReceivedCollection	Database received message collection name	string	cap.received
PublishedCollection	Database published message collection name	string	cap.published

Publish with transaction

The following example shows how to integrate CAP with MongoDB for local transactions:

// NOTE: Before testing, you need to create the database and collection first.
// MongoDB cannot automatically create databases and collections within transactions,
// so you must create them separately. For example, insert a record to auto-create the collection.

// var mycollection = _client.GetDatabase("test")
//          .GetCollection<BsonDocument>("test.collection");
// mycollection.InsertOne(new BsonDocument { { "test", "test" } });

using (var session = _client.StartTransaction(_capBus, autoCommit: false))
{
    var collection = _client.GetDatabase("test")
            .GetCollection<BsonDocument>("test.collection");

    collection.InsertOne(session, new BsonDocument { { "hello", "world" } });

    _capBus.Publish("sample.rabbitmq.mongodb", DateTime.Now);

    session.CommitTransaction();
}