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Mongo2Go is a managed wrapper around the latest MongoDB binaries. It targets .NET Standard 1.6 (and .NET 4.6 for legacy environments) and works with Windows, Linux and macOS. This Nuget package contains the executables of mongod, mongoimport and mongoexport for Windows, Linux and macOS .

Brought to you by Johannes Hoppe, follow him on Twitter.

Mongo2Go has two use cases:

1. Providing multiple, temporary and isolated MongoDB databases for unit tests (or to be precise: integration tests)
2. Providing a quick to set up MongoDB database for a local developer environment

With each call of the static method MongoDbRunner.Start() a new MongoDB instance will be set up. A free port will be used (starting with port 27018) and a corresponding data directory will be created. The method returns an instance of MongoDbRunner, which implements IDisposable. As soon as the MongoDbRunner is disposed (or if the Finalizer is called by the GC), the wrapped MongoDB process will be killed and all data in the data directory will be deleted.

In this mode a single MongoDB instance will be started on the default port (27017). No data will be deleted and the MongoDB instance won’t be killed automatically. Multiple calls to MongoDbRunner.StartForDebugging() will return an instance with the State “AlreadyRunning”. You can ignore the IDisposable interface, as it won’t have any effect. I highly recommend to not use this mode on productive machines! Here you should set up a MongoDB as it is described in the manual. For you convenience the MongoDbRunner also exposes mongoexport and mongoimport which allow you to quickly set up a working environment.

MongoDbRunner.Start() can be set up to take in an optional boolean parameter called singleNodeReplSet. When passed in with the value true - (MongoDbRunner.Start(singleNodeReplSet: true))

• a single node mongod instance will be started as a replica set with the name singleNodeReplSet. Replica set mode is required for transactions to work in MongoDB 4.0 or greater

MongoDbRunner.Start() can be set up to consume additional mongod arguments. This can be done using the string parameter called additionalMongodArguments. The list of additional arguments cannot contain arguments already defined internally by Mongo2Go. An ArgumentException will be thrown in this case, specifying which additional arguments are required to be discarded. Example of usage of the additional mongod arguments: MongoDbRunner.Start(additionalMongodArguments: "--quiet")

The Mongo2Go Nuget package can be found at https://nuget.org/packages/Mongo2Go/

Search for „Mongo2Go“ in the Manage NuGet Packages dialog box or run:

PM> Install-Package Mongo2Go

or run for the legacy .NET 4.6 package:

PM> Install-Package Mongo2Go -Version 1.1.0

in the Package Manager Console.

• The new 2.x branch targets .NET Standard 1.6, please use the latest packages if possible.
• The old 1.x branch targets good-old classic .NET 4.6.1. This is for legacy environments only. No new features will be added, only bugfixes will be made.

Example: Integration Test (here: Machine.Specifications & Fluent Assertions)

[Subject("Runner Integration Test")]
public class when_using_the_inbuild_serialization : MongoIntegrationTest
{
    static TestDocument findResult;
    
    Establish context = () =>
        {
            CreateConnection();
            _collection.Insert(TestDocument.DummyData1());
        };

    Because of = () => findResult = _collection.FindOneAs<TestDocument>();

    It should_return_a_result = () => findResult.ShouldNotBeNull();
    It should_hava_expected_data = () => findResult.ShouldHave().AllPropertiesBut(d => d.Id).EqualTo(TestDocument.DummyData1());

    Cleanup stuff = () => _runner.Dispose();
}

public class MongoIntegrationTest
{
    internal static MongoDbRunner _runner;
    internal static MongoCollection<TestDocument> _collection;

    internal static void CreateConnection()
    {
        _runner = MongoDbRunner.Start();
        
        MongoServer server = MongoServer.Create(_runner.ConnectionString);
        MongoDatabase database = server.GetDatabase("IntegrationTest");
        _collection = database.GetCollection<TestDocument>("TestCollection");
    }
}    

More tests can be found at https://github.com/Mongo2Go/Mongo2Go/tree/master/src/Mongo2GoTests/Runner

Example: Exporting seed data

using (MongoDbRunner runner = MongoDbRunner.StartForDebugging()) {

    runner.Export("TestDatabase", "TestCollection", @"..\..\App_Data\test.json");
}

Example: Importing for local debugging (compatible with ASP.NET MVC 4 Web API as well as ASP.NET Core)

public class WebApiApplication : System.Web.HttpApplication
{
    private MongoDbRunner _runner;

    protected void Application_Start()
    {
        _runner = MongoDbRunner.StartForDebugging();
        _runner.Import("TestDatabase", "TestCollection", @"..\..\App_Data\test.json", true);

        MongoServer server = MongoServer.Create(_runner.ConnectionString);
        MongoDatabase database = server.GetDatabase("TestDatabase");
        MongoCollection<TestObject> collection = database.GetCollection<TestObject>("TestCollection");

        /* happy coding! */
    }

    protected void Application_End()
    {
        _runner.Dispose();
    }
}

Example: Transactions (New feature since v2.2.8)

 public class when_transaction_completes : MongoTransactionTest
    {
        private static TestDocument mainDocument;
        private static TestDocument dependentDocument;
        Establish context = () =>

        {
            _runner = MongoDbRunner.Start(singleNodeReplSet: true);
             client = new MongoClient(_runner.ConnectionString);
            database = client.GetDatabase(_databaseName);
            _mainCollection = database.GetCollection<TestDocument>(_mainCollectionName);
            _dependentCollection = database.GetCollection<TestDocument>(_dependentCollectionName);
            _mainCollection.InsertOne(TestDocument.DummyData2());
            _dependentCollection.InsertOne(TestDocument.DummyData2());
        };

        private Because of = () =>
        {
            var filter = Builders<TestDocument>.Filter.Where(x => x.IntTest == 23);
            var update = Builders<TestDocument>.Update.Inc(i => i.IntTest, 10);

            using (var sessionHandle = client.StartSession())
            {
                try
                {
                    var i = 0;
                    while (i < 10)
                    {
                        try
                        {
                            i++;
                            sessionHandle.StartTransaction(new TransactionOptions(
                                readConcern: ReadConcern.Local,
                                writeConcern: WriteConcern.W1)); 
                            try
                            {
                                var first = _mainCollection.UpdateOne(sessionHandle, filter, update);
                                var second = _dependentCollection.UpdateOne(sessionHandle, filter, update);
                            }
                            catch (Exception e)
                            {
                                sessionHandle.AbortTransaction();
                                throw;
                            }

                            var j = 0;
                            while (j < 10)
                            {
                                try
                                {
                                    j++;
                                    sessionHandle.CommitTransaction();
                                    break;
                                }
                                catch (MongoException e)
                                {
                                    if (e.HasErrorLabel("UnknownTransactionCommitResult"))
                                        continue;
                                    throw;
                                }
                            }
                            break;
                        }
                        catch (MongoException e)
                        {
                            if (e.HasErrorLabel("TransientTransactionError"))
                                continue;
                            throw;
                        }
                    }
                }
                catch (Exception e)
                {
                    //failed after multiple attempts so log and do what is appropriate in your case
                }
            }

             mainDocument = _mainCollection.FindSync(Builders<TestDocument>.Filter.Empty).FirstOrDefault();
             dependentDocument = _dependentCollection.FindSync(Builders<TestDocument>.Filter.Empty).FirstOrDefault();
        };
        
        It main_should_be_33 = () => mainDocument.IntTest.Should().Be(33);
        It dependent_should_be_33 = () => dependentDocument.IntTest.Should().Be(33);
        Cleanup cleanup = () => _runner.Dispose();
    }

• allows additional custom MongoDB arguments (PR #68, fixes #68 - many thanks to José Mira)

• fixes a file path issue on Linux if you run on an SDK version beyond .NET Standard 1.6 (PR #63, fixes #62 and #61) - many thanks to Jeroen Vannevel)
• continuous integration runs on Linux (Travis CI) and Windows (AppVeyor) now

• updated MongoDB binaries to 4.0.2 to support tests leveraging transaction across different collections and databases
• updated MongoDB C# driver to 2.7.0 to be compatible with MongoDB 4.0
• adds singleNodeReplSet paramter to MongoDbRunner.Start which allows mongod instance to be started as a replica set to enable transaction support (PR #57 - many thanks to Mahi Satyanarayana)
• fixes port lookup for UnixPortWatcher (PR #58 - many thanks to Viktor Kolybaba)

• updates the MongoBinaryLocator to look for binaries in the nuget cache if they are not found in the project directory.
  • this will make Mongo2Go compatible with projects using the nuget PackageReference option. (PR #56, fixes #39 and #55)
• adds the binariesSearchDirectory parameter to MongoDbRunner.Start which allows an additional binaries search directory to be provided.
  • this will make the db runner more flexible if someone decides to use it in some unpredictable way.
• many thanks to Nicholas Markkula

• fixes broken linux support (fixes #47)

• fixes unresponsive process issue (PR #52, fixes #49)
• many thanks to narendrachava

• better support for TeamCity: removed MaxLevelOfRecursion limitation when searching for MongoDb binaries (PR #50, fixes #39)
• many thanks to Stanko Culaja

• includes mongod, mongoimport and mongoexport v3.6.1 for Windows, Linux and macOS via PR #46, which fixes #45
• many thanks to Joe Chan

• no MongoDB binaries changed, still .NET Standard 1.6
• feature: uses temporary directory instead of good-old windows style C:\data\db by default (PR #42) - MongoDbRunner.Start() and MongoDbRunner.StartForDebugging() will now work without any extra parameters for Linux/macOS
• bugfix: runs again on Linux/macOS, by making the binaries executable (PR #42, which fixes #37 and might also fix #43)
• internal: Unit Tests are running again (PR #44, which fixes #31, #40)
• internal: No hardcoded path passed to MongoDbRunner constructor (fixes 41)
• many thanks to Per Liedman

• includes mongod, mongoimport and mongoexport v3.4.7 for Windows, Linux and macOS
• targets .NET Standard 1.6 (can be used with .NET Core 1.0 / 1.1 / 2.0)
• many thanks to Aviram Fireberger

• skips v2.0 to have same numbers as v1.x.
• no MongoDB binaries changed since 2.0.0-alpha1 (still MongoDB v3.2.7 for Windows, Linux and macOS)
• targets .NET Standard 1.6 (can be used with .NET Core 1.0 / 1.1)
• bugfix: prevent windows firewall popup (PR #30, which fixes #21)
• many thanks to kubal5003

• no MongoDB binaries changed since v1.0 (still MongoDB v3.2.7 for Windows, Linux and macOS)
• targets .NET 4.6.1
• bugfix: prevent windows firewall popup (PR #29, which fixes #21)
• many thanks to kubal5003

• this version has no support for .NET Framework 4.6, please continue to use the stable package v.1.0.0
• NEW: first support of .NET Standard 1.6 (#25)
  • many thanks to Hassaan Ahmed
  • see the Wiki for more information about .NET Core 1.0 / .NET Standard 1.6

Just fork the project, make your changes send us a PR.
You can compile the project with Visual Studio 2017 and/or the .NET Core 2.0 CLI!

In the root folder, just run:

dotnet restore
dotnet build
dotnet test src/Mongo2GoTests