---
title: .NET / .NET Framework
slug: net-net-framework
docTags: 
createdAt: 2024-02-15T21:16:20.030Z
---

## Overview

This documentation will show you how to instrument your .NET applications to send OpenTelemetry traces to ObserveNow.

## Setup

### For apps running on .NET Auto Instrumentation

Install the following packages using `dotnet add package` command:

- [OpenTelemetry.Exporter.Console](https://www.nuget.org/packages/OpenTelemetry.Exporter.Console/): (Optional: For traces to be displayed on Console during development)
- [OpenTelemetry.Exporter.OpenTelemetryProtocol](https://www.nuget.org/packages/OpenTelemetry.Exporter.OpenTelemetryProtocol)
- [OpenTelemetry.Extensions.Hosting](https://www.nuget.org/packages/OpenTelemetry.Extensions.Hosting)
- [OpenTelemetry.Instrumentation.AspNetCore](https://www.nuget.org/packages/OpenTelemetry.Instrumentation.AspNetCore)

In the `*.csproj` file, the installed packages will look like:

```csharp
...
  <ItemGroup>
    ...
    <PackageReference Include="OpenTelemetry.Exporter.Console" Version="1.7.0" />
    <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.7.0" />
    <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.7.0" />
    <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.7.0" />
    ...
  </ItemGroup>
...
```

### Configuration

Paste the below code snippet in the `Program.cs` file

```csharp
// Import necessary packages
using System.Diagnostics;
using OpenTelemetry.Exporter;
using OpenTelemetry.Resources;
using OpenTelemetry.Trace;
using OpenTelemetry.Exporter.OpenTelemetryProtocol;

...

// Configure OpenTelemetry settings
var builder = WebApplication.CreateBuilder(args);

builder.Services.AddOpenTelemetry()
    .ConfigureResource(resource => resource.AddService("<service_name>"))
    .WithTracing(tracing =>
    {
        tracing.AddAspNetCoreInstrumentation();
        // tracing.AddConsoleExporter(); (Used only for development purposes)
        tracing.AddOtlpExporter(opt =>
        {
            opt.Endpoint = new Uri("<otel_collector_endpoint>");
            opt.Protocol = OpenTelemetry.Exporter.OtlpExportProtocol.Grpc;
        });
    });

var app = builder.Build();

...
```

### For apps running on .NET Framework 4.8.x Instrumentation - Manual

Install the following packages using `dotnet add package` command or NuGet package manager:

- [OpenTelemetry](https://www.nuget.org/packages/OpenTelemetry)
- [OpenTelemetry.Exporter.OpenTelemetryProtocol](https://www.nuget.org/packages/OpenTelemetry.Exporter.OpenTelemetryProtocol)
- [OpenTelemetry.Instrumentation.HTTP](https://www.nuget.org/packages/OpenTelemetry.Instrumentation.Http)
- [OpenTelemetry.Instrumentation.AspNetCore](https://www.nuget.org/packages/OpenTelemetry.Instrumentation.AspNetCore)
- [OpenTelemetry.Exporter.Console](https://www.nuget.org/packages/OpenTelemetry.Exporter.Console) (Optional: For traces to be displayed on Console during development)

In the `*.csproj` file, the installed packages will look like:

```csharp
...
  <ItemGroup>
    ...
    <PackageReference Include="OpenTelemetry" Version="1.7.0" />
    <PackageReference Include="OpenTelemetry.Exporter.Console" Version="1.7.0" />
    <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.7.0" />
    <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.7.0" />
    <PackageReference Include="OpenTelemetry.Instrumentation.HTTP" Version="1.7.0" />
    ...
  </ItemGroup>
...
```

### Configuration

Paste the below code snippet in the `Program.cs` file

```csharp
// Import necessary packages
using System.Diagnostics;
using Microsoft.Extensions.Configuration;
using OpenTelemetry;
using OpenTelemetry.Exporter;
using OpenTelemetry.Trace;
using System;
using System.Net.Http.Headers;
using System.Net.Http;
using System.Threading.Tasks;
using OpenTelemetry.Resources;

...

public class Program
{
    ...
    private static readonly ActivitySource MyActivitySource = new ActivitySource("MyCompany.MyProduct.MyLibrary");

    public static void Main()
    {
        var tracerProvider = Sdk.CreateTracerProviderBuilder()
            .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("<service_name>"))
            // The following subscribes to activities from Activity Source MyCompany.MyProduct.MyLibrary
            .AddSource("MyCompany.MyProduct.MyLibrary")
            // .AddConsoleExporter() (Used only for development purposes)
            .AddOtlpExporter(opt =>
            {
                opt.Endpoint = new Uri("<otel_collector_endpoint>");
                opt.Protocol = OtlpExportProtocol.Grpc;
            })
            .Build();

        // You can also set custom tags to the trace information
        // NOTE: This is used for testing and can be deleted once testing is done.
        using (var activity = MyActivitySource.StartActivity("<activity_name>"))
        {
            activity?.SetTag("foo", 1);
            activity?.SetTag("bar", "Hello, World!");
            activity?.SetTag("baz", new int[] { 1, 2, 3 });
            activity?.SetStatus(ActivityStatusCode.Ok);
        }

        // Dispose tracer provider before the application ends.
        // This will flush the remaining spans and shutdown the tracing pipeline.
        tracerProvider.Dispose();
    }
    ...
}
```

:::hint{type="success"}
Every activity source which produce telemetry must be explicitly added to the tracer provider to start collecting traces from them. `AddSource` method on `TracerProviderBuilder` can be used to add a `ActivitySource` to the provider. The name of the `ActivitySource` (case-insensitive) must be the argument to this method.
:::

:::hint{type="info"}
Ensure that the OpsVerse Agent otel-collector is accessible from your .NET application environnment, either using an ingress or an IP
:::

## Adding Custom Span Attributes

Custom span attributes can be added at the service level or at (*more granular*) trace level. For service level span attributes, you can configure an environment variable `OTEL_RESOURCE_ATTRIBUTES` with key value pairs. For eg.

```shell
OTEL_RESOURCE_ATTRIBUTES=key1=value1,key2=value2
```

These will be picked up by the OpenTelemetry SDK and be brought into traces in your ObserveNow Instance.

For granular, trace level attributes, you can leverage `ActivitySource` to add custom span attributes. This is somewhat similar to the [manual instrumentation](https://docs.opsverse.io/net-net-framework#6rkb4) steps above:

```csharp
using System.Diagnostics;
.
.
  [HttpGet]
  public IActionResult Get()
  {
    var activitySource = new ActivitySource("MyCompany.MyProduct.MyLibrary");
    using (var activity = activitySource.StartActivity("<activity_name>"))
    {
       activity?.SetTag("<custom_attr_key>", "<custom_attr_value>");
       // Rest of your logic
    }
  }
.
.
```

::Image[]{src="https://api.archbee.com/api/optimize/xpy-ZuNXAextve6S5Tto2/vbDzD3T1EJOTOH-rM1HRG_screenshot-2024-06-21-at-11404-am.png" size="60" width="1012" height="720" position="center" caption="Custom Span Attributes" alt="Custom Span Attributes" showCaption="true"}