Connecting manually instrumented spans with automatically instrumented OTel spans

[aldy505]

Description

SInce we have IDisposable implemented for ISpan interface (PR #4627), is there any way to connect a parent of manually instrumented spans with a child span of automatically instrumented OTel span?

This is my current setup:

builder.Services.AddOpenTelemetry()
    .WithTracing(tracerProviderBuilder =>
        tracerProviderBuilder
            .AddSource("MyProgram")
            .AddAspNetCoreInstrumentation()
            .AddRedisInstrumentation()
            .AddHttpClientInstrumentation()
            .AddGrpcClientInstrumentation()
            .AddNpgsql()
            .AddSentry()
    );

builder.WebHost.UseSentry(options => {
    options.SampleRate = (float?)1.0;
    options.TracesSampleRate = 1.0;
    options.SendDefaultPii = true;
    options.UseOpenTelemetry();
    options.DisableSentryHttpMessageHandler = true;
});

With this current setup, I always use ActivitySource on my application-level methods, like so:

public class PasswordManagementService() {
    private static readonly ActivitySource ActivitySource = new("MyProgram");

    public async Task ChangePassword(ChangePasswordRequest request, CancellationToken cancellationToken) {
        using Activity? activity = ActivitySource.StartActivity();
        // do things
        // queries to PostgreSQL here
    }
}

The span is connected, but sadly it won't connect the errors perfectly. What I want to do is to directly use the StartSpan() method from Sentry, while still having the trace of PostgreSQL query from OTel being a child of the said span. Therefore the code will become:

public class PasswordManagementService() {
    public async Task ChangePassword(ChangePasswordRequest request, CancellationToken cancellationToken) {
        using var span = SentrySdk.StartSpan(operation: "function", description: "ChangePassword");
        // do things
        // queries to PostgreSQL here (using OTel, as I want to capture it automatically)
    }
}

Is there any workaround for this other than creating the span for PostgreSQL database operation manually?

[linear-code]

NET-646

[jamescrosswell]

You could try StartSpan:

sentry-dotnet/src/Sentry/HubExtensions.cs

Lines 54 to 62 in 48b744f

	/// <summary>
	/// Starts a span or transaction if a transaction is not already active on the scope
	/// </summary>
	public static ISpan StartSpan(this IHub hub, string operation, string description)
	{
	return hub.GetTransaction() is { } transaction
	? transaction.StartChild(operation, description)
	: hub.StartTransaction(operation, description); // this is actually in the wrong order but changing it may break other things
	}

When open telemetry spans pass through Sentry's span processor, they get stored on the scope so that the Sentry instrumentation can know there's already an active trace/span... and can create child spans of this:

sentry-dotnet/src/Sentry.OpenTelemetry/SentrySpanProcessor.cs

Line 175 in 54511b5

_hub.ConfigureScope(static (scope, transaction) => scope.Transaction = transaction, transaction);

That said, this interleaving of Sentry and OpenTelemetry spans is probably something we're going to phase out.

[aldy505]

Ah so what I'm trying to do is supported, but it's not recommended anymore?

[jamescrosswell]

Ah so what I'm trying to do is supported, but it's not recommended anymore?

Yeah it's something we have tried to support and it mostly works. Essentially it's mixing instrumentation from two different tracing frameworks though and sometimes you end up with odd results.

With this current setup, I always use ActivitySource on my application-level methods
The span is connected, but sadly it won't connect the errors perfectly.

What isn't perfect about the association of errors with OpenTelemetry spans? If you are using OTEL instrumentation, that's probably the better thing to resolve.