Introduction:

Distributed tracing is a crucial technique used in modern software systems that involves tracing the lifecycle of a request as it moves through different components of a distributed system. It allows developers to identify performance bottlenecks, troubleshoot issues, and optimize system performance. OpenTelemetry is a popular open-source tool for implementing distributed tracing, providing a standardized API and integration with many different frameworks and languages. In this article, we will explore how to implement distributed tracing using OpenTelemetry in .NET Core.

What is OpenTelemetry?

OpenTelemetry is an open-source project that provides a vendor-agnostic API for distributed tracing, metrics, and logging. It allows developers to instrument their applications and gather data about the performance and behavior of their systems. OpenTelemetry provides a set of standard APIs and protocols that can be used across different languages, platforms, and frameworks. It also provides integrations with many different monitoring and observability tools, making it easier to analyze and visualize the data collected by the instrumentation.

How to Implement Distributed Tracing with OpenTelemetry in .NET Core?

To implement distributed tracing with OpenTelemetry in .NET Core, we need to follow these steps:

Step 1: Add OpenTelemetry to the .NET Core application

The first step is to add the OpenTelemetry packages to the .NET Core application. We can use NuGet to add the OpenTelemetry packages to our project. OpenTelemetry provides a set of packages for different components, including the SDK, exporters, and instrumentation libraries. We will use the following packages:

• OpenTelemetry.Extensions.Hosting
• OpenTelemetry.Exporter.Jaeger
• OpenTelemetry.Instrumentation.AspNetCore
• OpenTelemetry.Instrumentation.SqlClient

The OpenTelemetry.Extensions.Hosting package provides extensions for integrating OpenTelemetry with .NET Core. The OpenTelemetry.Exporter.Jaeger package provides an exporter that sends tracing data to the Jaeger backend. The OpenTelemetry.Instrumentation.AspNetCore package provides instrumentation for ASP.NET Core applications, and the OpenTelemetry.Instrumentation.SqlClient package provides instrumentation for SQL Server client libraries.

Step 2: Configure OpenTelemetry

The next step is to configure OpenTelemetry. We can use the ConfigureServices method in the Startup class to configure OpenTelemetry. We need to add the OpenTelemetry services to the service collection and configure the exporter and instrumentation options.

Here is an example of how to configure OpenTelemetry with Jaeger exporter and ASP.NET Core instrumentation:

public void ConfigureServices(IServiceCollection services)
{
    services.AddOpenTelemetryTracing(builder =>
    {
        builder
            .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("MyService"))
            .AddAspNetCoreInstrumentation()
            .AddSqlClientInstrumentation()
            .AddJaegerExporter(options =>
            {
                options.AgentHost = "localhost";
                options.AgentPort = 6831;
            });
    });
}

In this example, we are configuring OpenTelemetry to use the Jaeger exporter and the ASP.NET Core and SQL Server client instrumentation libraries. We are also setting the service name to "MyService" in the resource builder.

Step 3: Instrument the application

The next step is to instrument the application. We need to add instrumentation to the different components of the application to capture tracing data. The ASP.NET Core instrumentation library automatically instruments the HTTP requests, but we need to instrument other components manually. For example, we can instrument the SQL Server client by using the following code:

using (var connection = new SqlConnection(connectionString))
{
    using var command = new SqlCommand("SELECT * FROM Customers", connection);
    using var scope = Tracer.Current.StartActiveSpan("SqlQuery");
    command.ExecuteReader();
}

In this example, we are creating a new SqlConnection and SqlCommand object to execute a SQL query. We are also creating a new span using the Tracer.Current.StartActiveSpan method, which starts a new span and sets it as the current active span. This will ensure that any child spans created within the scope of this span will be linked to this span.

Step 4: View the tracing data

The final step is to view the tracing data. We can use the Jaeger backend to visualize the tracing data. Jaeger is an open-source distributed tracing system that provides a web-based UI for viewing traces. We can download the Jaeger backend from the Jaeger website and run it locally or use a cloud-based service like JaegerCloud. Once the Jaeger backend is running, we can configure the OpenTelemetry Jaeger exporter to send the tracing data to Jaeger.

To view the tracing data in Jaeger, we can open the Jaeger UI and search for the traces by service name or operation name. We can view the trace details, including the duration, spans, and tags. We can also view the trace graph, which shows the dependencies between the different spans.

Conclusion:

Distributed tracing is an essential technique for monitoring and debugging modern software systems. OpenTelemetry is a popular open-source tool for implementing distributed tracing, providing a standardized API and integration with many different frameworks and languages.

In this article, we explored how to implement distributed tracing using OpenTelemetry in .NET Core. We covered the steps to add OpenTelemetry to the .NET Core application, configure OpenTelemetry, instrument the application, and view the tracing data. By implementing distributed tracing with OpenTelemetry, we can gain valuable insights into the performance and behavior of our systems and improve their reliability and scalability.