How can add Activity in MongoDB C# driver for Serializer/ Deserializer operations?

Question

I would like to add activity (for logging) in MongoDB to trace MongoDB operations, specifically on serialize/deserialize operations.

I use official MongoDB driver : https://www.nuget.org/packages/mongodb.driver/

Ideally, I search a way to add activity on all serialize/ deserialize operations without change in source code of Mongodb.driver but it's seems... complicate...

For some class I use a custom ClassMap with RegisterClassMap like this one :

BsonClassMap.RegisterClassMap<MyClasse>(cm =>
{
   cm.AutoMap();
   cm.SetIgnoreExtraElements(true);
});

If I could add activities within this class, that might be enough.

I found this nuggets package which provide activity in MongoDB operation, but it's not encapsulate serialize/ deserialize time.

if anyone has any ideas, I'd love to hear from you. Thanks in advance

Answer 1

While the MongoDB C# driver itself doesn't provide built-in support for tracing at such a fine-grained level, you should be able to achieve this by instrumenting your code using the .NET DiagnosticSource framework.

Here is one way you could achive this:

Wrap your custom class mappings with DiagnosticSource activities. You've already shown an example of how you use custom class maps, add tracing activities within these methods:

BsonClassMap.RegisterClassMap<MyClasse>(cm =>
{
    cm.AutoMap();
    cm.SetIgnoreExtraElements(true);

    // Wrap serialize and deserialize methods with DiagnosticSource activities
    cm.MapMember(c => c.MyProperty)
        .SetSerializer(SerializerBuilder.Build(typeof(MyPropertySerializer)));
});

Here, SerializerBuilder.Build should be a custom serializer that wraps serialization and deserialization operations with DiagnosticSource activities.

Then create your own DiagnosticSource events for MongoDB operations and subscribe to these events to log them or perform other actions.

using System.Diagnostics;

private static readonly DiagnosticSource mongoDbDiagnosticSource = new DiagnosticListener("MongoDBDiagnosticSource");

// Somewhere in your code, when you want to trace an operation:
var activity = new Activity("MongoDBSerialize");
activity.Start();

// Capture additional information if needed
activity.AddTag("CollectionName", "MyCollection");

mongoDbDiagnosticSource.Write(
    "MongoDBSerialize.Start",
    new { Activity = activity });

// ... Perform your MongoDB operation ...

activity.Stop();
mongoDbDiagnosticSource.Write("MongoDBSerialize.Stop", new { Activity = activity });

You'll need to create similar instrumentation for deserialize operations.

You'll need to subscribe to the DiagnosticSource events you've created in your code to log or analyze the tracing information.

var listener = new MyDiagnosticListener();
mongoDbDiagnosticSource.Subscribe(listener);

Here, MyDiagnosticListener is a custom class you'll create to handle the events and perform actions like logging.

Implement MyDiagnosticListener:

Create a class to handle the events, where you can log the tracing information or take any other desired action.

public class MyDiagnosticListener
{
    public void OnMongoDBSerializeStart(Activity activity)
    {
        // Log or process the start of MongoDB serialization
    }

    public void OnMongoDBSerializeStop(Activity activity)
    {
        // Log or process the end of MongoDB serialization
    }
}

Hope this helps you understand how to capture detailed information about serialize/deserialize operations and log them as needed.

Alternativly you could use the .NET Core ILogger frameworks, such as NLog or Serilog to achieve logging and tracing of MongoDB operations. That way you'd provide a way to integrate MongoDB operation logging with the existing logging infrastructure in your application.

Using the ILogger should be a bit easier to integrate. You can configure it during your application startup:

using Microsoft.Extensions.Logging;
using MongoDB.Driver.Extensions.Logging;

var loggerFactory = LoggerFactory.Create(builder =>
{
    builder.AddConsole(); // Configure the logging provider you prefer or use appsettings based configuration
});

// Use the LoggerFactory to create a logger and pass it to the MongoDB driver
var mongoClientSettings = MongoClientSettings
    .FromConnectionString("your-connection-string");
mongoClientSettings.LoggerFactory = loggerFactory;
var mongoClient = new MongoClient(mongoClientSettings);