.NET Sample Application with OpenTelemetry Tracing

A sample .NET Web API application demonstrating distributed tracing with OpenTelemetry. The application implements a simple order processing system where you can create and retrieve orders, with all operations being traced and monitored with OpenObserve.

About the Demo Application

This demo implements two main endpoints:

• POST /order - Create a new order
• GET /order/{id} - Retrieve an order by ID

Each endpoint is instrumented with OpenTelemetry to capture:

• HTTP request details
• Order processing operations
• External service calls
• Error scenarios

Prerequisites

• .NET SDK 6.0 or newer
• OpenObserve: You can get started with OpenObserve Cloud or a self hosted installation.

Getting Started

1. Clone the Repository:

git clone https://github.com/openobserve/dotnet-opentelemetry-tracing-application
cd dotnet-opentelemetry-tracing-application

2. Add Required Packages:

# Add core OpenTelemetry packages
dotnet add package OpenTelemetry --version 1.7.0
dotnet add package OpenTelemetry.Extensions.Hosting --version 1.7.0
dotnet add package OpenTelemetry.Instrumentation.AspNetCore --version 1.7.0
dotnet add package OpenTelemetry.Exporter.OpenTelemetryProtocol --version 1.7.0
dotnet add package OpenTelemetry.Instrumentation.Http --version 1.7.0
dotnet add package OpenTelemetry.Exporter.Console --version 1.7.0

# Add Swagger for API documentation
dotnet add package Swashbuckle.AspNetCore --version 6.5.0

3. Restore Dependencies:

dotnet restore

4. Configure OpenTelemetry:

Update Program.cs with your OpenObserve credentials. You can find these in OpenObserve UI under Data Sources → Custom → Traces → OpenTelemetry → OTLP HTTP.

builder.Services.AddOpenTelemetry()
    .WithTracing(builder => builder
        .SetResourceBuilder(resourceBuilder)
        .AddSource(TracingInstrumentation.ServiceName)
        .AddAspNetCoreInstrumentation()
        .AddHttpClientInstrumentation()
        .AddOtlpExporter(opts =>
        {
            opts.Endpoint = new Uri("your_openobserve_url/v1/traces");
            opts.Headers = "Authorization=Basic YOUR_AUTH_TOKEN";
            opts.Protocol = OpenTelemetry.Exporter.OtlpExportProtocol.HttpProtobuf;
        }));

Note: Remember to add /v1/traces to your OTLP HTTP endpoint

5. Run the Application:

dotnet run

Using the API

1. Access Swagger UI:

   • Open https://localhost:5xxx/swagger in your browser
   • The exact port will be shown in the console when you run the application

2. Create an Order:

   • Using Swagger UI: Try the POST /order endpoint
   • Using curl:

curl -X POST https://localhost:5xxx/order \
  -H "Content-Type: application/json" \
  -d '{"customerName":"John Doe","amount":99.99}' \
  -k

3. Retrieve an Order:
   • Using Swagger UI: Try the GET /order/{id} endpoint
   • Using curl:

curl -k https://localhost:5xxx/order/1

Viewing Traces in OpenObserve

1. Navigate to the Traces section
2. You should see traces appearing after making API requests

Note: There might be a slight delay before traces appear due to batching and export intervals

Troubleshooting

If traces aren't appearing in OpenObserve:

• Verify your OpenObserve endpoint URL and authentication token
• Check if you've added /v1/traces to the endpoint URL
• Make some API requests to generate traces
• Wait a few moments for traces to be exported
• Check the application console for any export errors