Instrument your .NET application with OpenTelemetry

This walkthrough shows how to add observability to your .NET application using the OpenTelemetry .NET libraries and tools.

Feature

Supported

Automatic instrumentation

Yes

Traces

Yes

Metrics

Yes

Logs

Yes

Prerequisites

Dynatrace version 1.254+
For tracing, W3C Trace Context is enabled
1. Go to Settings > Preferences > OneAgent features.
2. Turn on Send W3C Trace Context HTTP headers.

Get the Dynatrace access details

Determine the API base URL

For details on how to assemble the base OTLP endpoint URL, see Export with OTLP. The URL should end in /api/v2/otlp.

Get API access token

The access token for ingesting traces, logs, and metrics can be generated under Access Tokens.

Export with OTLP has more details on the format and the necessary access scopes.

Choose how you want to instrument your application

For .NET, OpenTelemetry supports automatic and manual instrumentation (or a combination of both).

Which instrumentation should I choose?

It's a good idea to start with automatic instrumentation and add manual instrumentation if the automatic approach doesn't work or doesn't provide enough information.

Automatically instrument your application optional

.NET automatic instrumentation can be configured either during development or later after deployment.

Enrichment with OneAgent

It is currently not possible to enrich automatically instrumented services with host-relevant information. To achieve this, you'd need to switch to manual instrumentation.

Install OpenTelemetry.Extensions.Hosting.

dotnet add package OpenTelemetry.Extensions.Hosting

Install the appropriate instrumentation library for your .NET framework (full list available here).
```
dotnet add package OpenTelemetry.Instrumentation.[FRAMEWORK_NAME]
```

In addition to the instrumentation setup above, you also need to configure the relevant export parameters with environment variables. This includes the endpoint URL, the authentication token, and the temporality preference for metrics.

OTEL_EXPORTER_OTLP_ENDPOINT=[URL]
OTEL_EXPORTER_OTLP_HEADERS="Authorization=Api-Token [TOKEN]"
OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE=delta

Manually instrument your application optional

Setup

The setup steps slightly differ depending on whether you instrument a plain .NET application or an ASP.NET application.

Install the following packages.

dotnet add package Microsoft.Extensions.Logging
dotnet add package OpenTelemetry.Extensions.Hosting
dotnet add package OpenTelemetry
dotnet add package OpenTelemetry.Api
dotnet add package OpenTelemetry.Exporter.OpenTelemetryProtocol

Add the following using statements to the startup class, which bootstraps your application.

using OpenTelemetry;
using OpenTelemetry.Trace;
using OpenTelemetry.Exporter;
using OpenTelemetry.Metrics;
using OpenTelemetry.Logs;
using OpenTelemetry.Resources;
using OpenTelemetry.Context.Propagation;
using System.Diagnostics;
using System.Diagnostics.Metrics;
using Microsoft.Extensions.Logging;

Add these fields to your startup class, with the first two containing the access details, if you are using the OTLP export.

private static string DT_API_URL = ""; // TODO: Provide your SaaS/Managed URL here
private static string DT_API_TOKEN = ""; // TODO: Provide the OpenTelemetry-scoped access token here

private const string activitySource = "Dynatrace.DotNetApp.Sample"; // TODO: Provide a descriptive name for your application here
public static readonly ActivitySource MyActivitySource = new ActivitySource(activitySource);
private static ILoggerFactory loggerFactoryOT;

Value injection

Instead of hardcoding the URL and token, you might also consider reading them from storage specific to your application framework (for example, environment variables or framework secrets).

Add the initOpenTelemetry method to your startup class and invoke it as early as possible during your application startup. This initializes OpenTelemetry for the Dynatrace backend and creates default tracer and meter providers.

private static void initOpenTelemetry(IServiceCollection services)
{
    List<KeyValuePair<string, object>> dt_metadata = new List<KeyValuePair<string, object>>();
    foreach (string name in new string[] {"dt_metadata_e617c525669e072eebe3d0f08212e8f2.properties",
                                          "/var/lib/dynatrace/enrichment/dt_metadata.properties",
                                          "/var/lib/dynatrace/enrichment/dt_host_metadata.properties"}) {
        try {
            foreach (string line in System.IO.File.ReadAllLines(name.StartsWith("/var") ? name : System.IO.File.ReadAllText(name))) { 
                var keyvalue = line.Split("=");
                dt_metadata.Add( new KeyValuePair<string, object>(keyvalue[0], keyvalue[1]));
            }
        }
        catch { }
    }
    
    Action<ResourceBuilder> configureResource = r => r
        .AddService(serviceName: "dotnet-quickstart") //TODO Replace with the name of your application
        .AddAttributes(dt_metadata);
    
    services.AddOpenTelemetry()
        .ConfigureResource(configureResource)
        .WithTracing(builder => {
            builder
                .SetSampler(new AlwaysOnSampler())
                .AddSource(MyActivitySource.Name)
                .AddOtlpExporter(options => 
                {
                    options.Endpoint = new Uri(Environment.GetEnvironmentVariable("DT_API_URL")+ "/v1/traces");
                    options.Protocol = OpenTelemetry.Exporter.OtlpExportProtocol.HttpProtobuf;
                    options.Headers = $"Authorization=Api-Token {Environment.GetEnvironmentVariable("DT_API_TOKEN")}";
                });
        })
        .WithMetrics(builder => {
            builder
                .AddMeter("my-meter")
                .AddOtlpExporter((OtlpExporterOptions exporterOptions, MetricReaderOptions readerOptions) =>
                {
                    exporterOptions.Endpoint = new Uri(Environment.GetEnvironmentVariable("DT_API_URL")+ "/v1/metrics");
                    exporterOptions.Headers = $"Authorization=Api-Token {Environment.GetEnvironmentVariable("DT_API_TOKEN")}";
                    exporterOptions.Protocol = OpenTelemetry.Exporter.OtlpExportProtocol.HttpProtobuf;
                    readerOptions.TemporalityPreference = MetricReaderTemporalityPreference.Delta;
                });
            });
    
    var resourceBuilder = ResourceBuilder.CreateDefault();
    configureResource!(resourceBuilder);
    
    loggerFactoryOT = LoggerFactory.Create(builder => {
        builder
            .AddOpenTelemetry(options => {
                options.SetResourceBuilder(resourceBuilder).AddOtlpExporter(options => {
                    options.Endpoint = new Uri(Environment.GetEnvironmentVariable("DT_API_URL")+ "/v1/logs");
                    options.Headers = $"Authorization=Api-Token {Environment.GetEnvironmentVariable("DT_API_TOKEN")}";
                    options.ExportProcessorType = OpenTelemetry.ExportProcessorType.Batch;
                    options.Protocol = OtlpExportProtocol.HttpProtobuf;
                });
            })
            .AddConsole();
    });
    Sdk.CreateTracerProviderBuilder()
        .SetSampler(new AlwaysOnSampler())
        .AddSource(MyActivitySource.Name)
        .ConfigureResource(configureResource);
    // add-logging
}

Dynatrace data enrichment

The file read operations, parsing the dt_metadata files in the example code, attempt to read the OneAgent data files to enrich the OTLP request and ensure that all relevant topology information is available within Dynatrace.

Add tracing

Using MyActivitySource from the setup step, we can now start new activities (traces):

using var activity = Startup.MyActivitySource.StartActivity("Call to /myendpoint", ActivityKind.Consumer, parentContext.ActivityContext);
activity?.SetTag("http.method", "GET");
activity?.SetTag("net.protocol.version", "1.1");

In the above code, we:

Create a new activity (span) and name it "Call to /myendpoint"
Add two tags (attributes), following the semantic naming convention, specific to the action of this span: information on the HTTP method and version

The activity will be automatically set as the current and active span until the execution flow leaves the current method scope. Subsequent activities will automatically become child spans.

Collect metrics

To instantiate new metric instruments, we first need a meter object.

private static readonly Meter meter = new Meter("my-meter", "1.0.0");  //TODO Replace with the name of your meter

With meter, we can now create individual instruments, such as a counter.

private static readonly Counter<long> counter = meter.CreateCounter<long>("request_counter");

We can now invoke the Add() method of counter to record new values with our counter and save additional attributes (for example, action.type).
```
counter.Add(1, new("ip", "an ip address here"), new("some other key", "some other value"));
```

Connect logs

With the loggerFactoryOT variable, we initialized under Setup, we can now create individual logger instances, which will pass logged information straight to the configured OpenTelemetry endpoint at Dynatrace.

var logger = loggerFactoryOT.CreateLogger<Startup>();
services.AddSingleton<ILoggerFactory>(loggerFactoryOT);
services.AddSingleton(logger);
logger.LogInformation(eventId: 123, "Log line");

Ensure context propagation optional

Context propagation is particularly important when network calls (for example, REST) are involved.

If you are using automatic instrumentation and your networking libraries are covered by automatic instrumentation, this will be automatically taken care of by the instrumentation libraries. Otherwise, your code needs to take this into account.

Extracting the context when receiving a request

In the following example, we assume that we have received a network call via System.Web.HttpRequest and we define a CompositeTextMapPropagator instance to fetch the context information from the HTTP headers. We then pass that instance to Extract(), returning the context object, which allows us to continue the previous trace with our spans.

private CompositeTextMapPropagator propagator = new CompositeTextMapPropagator(new TextMapPropagator[] {
    new TraceContextPropagator(),
    new BaggagePropagator(),
});
private static readonly Func<HttpRequest, string, IEnumerable<string>> valueGetter = (request, name) => request.Headers[name];


var parentContext = propagator.Extract(default, HttpContext.Request, valueGetter);

using var activity = MyActivitySource.StartActivity("my-span", ActivityKind.Consumer, parentContext.ActivityContext);

Injecting the context when sending requests

In the following example, we send a REST request to another service and provide our existing context as part of the HTTP headers of our request.

To do so, we define a TextMapPropagator instance, which adds the respective information. Once we have instantiated our REST object, we pass it, along with the context and the setter instance, to Inject(), which will add the necessary headers to the request.

private CompositeTextMapPropagator propagator = new CompositeTextMapPropagator(new TextMapPropagator[] {
    new TraceContextPropagator(),
    new BaggagePropagator()
});

private static Action<HttpRequestMessage, string, string> _headerValueSetter => (request, name, value) => {
    request.Headers.Remove(name);
    request.Headers.Add(name, value);
};

propagator.Inject(new PropagationContext(activity!.Context, Baggage.Current), request, _headerValueSetter);

Configure data capture to meet privacy requirements optional

While Dynatrace automatically captures all OpenTelemetry attributes, only attribute values specified in the allowlist are stored and displayed in the Dynatrace web UI. This prevents accidental storage of personal data, so you can meet your privacy requirements and control the amount of monitoring data stored.

To view your custom attributes, you need to allow them in the Dynatrace web UI first. To learn how to configure attribute storage and masking, see Attribute redaction.

Verify data ingestion into Dynatrace

Once you have finished the instrumentation of your application, perform a couple of test actions to create and send demo traces, metrics, and logs and verify that they were correctly ingested into Dynatrace.

To do that for traces, go to Distributed Traces and select the Ingested traces tab. If you use OneAgent, select PurePaths instead.

For metrics and logs, go to Metrics or Logs.