Set up EDOT .NET for console applications

Elastic Stack Serverless Observability

You can instrument console applications using the Elastic Distribution of OpenTelemetry .NET. Applications running without a host can initialize OpenTelemetry manually. For example:

using OpenTelemetry;

using OpenTelemetrySdk sdk = OpenTelemetrySdk.Create(builder => builder
   .WithElasticDefaults());

The preceding code:

1. Imports the required types from the OpenTelemetry namespace.
2. Creates an instance of the OpenTelemetrySdk using its factory Create method.
3. Configures the IOpenTelemetryBuilder by passing a lambda.
4. Enables EDOT .NET and its opinionated defaults by calling WithElasticDefaults on the IOpenTelemetryBuilder.

When building console applications, consider using the features provided by Microsoft.Extensions.Hosting as this turns on dependency injection and logging capabilities.

The previous code is sufficient for many applications to achieve a reasonable out-of-the-box experience. The IOpenTelemetryBuilder can be further configured as required within the target application.

For example, you can observe an additional ActivitySource by chaining a call to WithTracing, providing a lambda to configure the TracerProviderBuilder to add the name of the additional ActivitySource.

using OpenTelemetry;
using OpenTelemetry.Trace;

using OpenTelemetrySdk sdk = OpenTelemetrySdk.Create(builder => builder
   .WithElasticDefaults()
   .WithTracing(t => t.AddSource("MyApp.SourceName")));

You can further customize the OpenTelemetry SDK with the other built-in extension methods, such as ConfigureResource.

using OpenTelemetry;
using OpenTelemetry.Trace;
using OpenTelemetry.Resources;

using OpenTelemetrySdk sdk = OpenTelemetrySdk.Create(builder => builder
   .WithElasticDefaults()
   .ConfigureResource(r => r.AddService("MyAppName"))
   .WithTracing(t => t.AddSource("MyApp.SourceName")));

When calling OpenTelemetrySdk.Create a dedicated IServiceCollection and IServiceProvider is created for the SDK and shared by all signals. An IConfiguration is created automatically from environment variables. The recommended method to configure the OpenTelemetry SDK is via environment variables. At a minimum, set the environment variables used to configure the OTLP exporter using any suitable method for your operating system.

"OTEL_EXPORTER_OTLP_ENDPOINT" = "https://{MyServerlessEndpoint}.apm.us-east-1.aws.elastic.cloud:443",
"OTEL_EXPORTER_OTLP_HEADERS" = "Authorization=ApiKey {MyEncodedApiKey}"

Replace the {MyServerlessEndpoint} and {MyEncodedApiKey} placeholders above with the values provided by your Elastic Observability backend.

Several configuration settings are available to control the additional features offered by EDOT .NET. These might be configured using environment variables, IConfiguration and/or code-based configuration. Refer to Configuration documentation for more details.

As an example, manual code-based configuration can be used to disable the instrumentation assembly scanning feature.

using OpenTelemetry;
using OpenTelemetry.Trace;
using OpenTelemetry.Resources;
using Elastic.OpenTelemetry;

var options = new ElasticOpenTelemetryOptions
{
	SkipInstrumentationAssemblyScanning = true
};

using OpenTelemetrySdk sdk = OpenTelemetrySdk.Create(builder => builder
   .WithElasticDefaults(options)
   .ConfigureResource(r => r.AddService("MyAppName3"))
   .WithTracing(t => t.AddSource("MyApp.SourceName")));

The preceding code:

1. Creates an instance of ElasticOpenTelemetryOptions.
2. Configures SkipInstrumentationAssemblyScanning as true to disable the assembly scanning feature.
3. Passes the ElasticOpenTelemetryOptions from the options variable into the WithElasticDefaults method.

You can also use IConfiguration to control EDOT .NET.

using OpenTelemetry;
using OpenTelemetry.Trace;
using OpenTelemetry.Resources;
using Microsoft.Extensions.Configuration;

const string edotPrefix = "Elastic:OpenTelemetry:";

var config = new ConfigurationBuilder()
   .AddJsonFile("appsettings.json")
   .AddInMemoryCollection(new Dictionary<string, string?>()
   {
      [$"{edotPrefix}SkipInstrumentationAssemblyScanning"] = "true",
      [$"{edotPrefix}LogDirectory"] = "C:\\Logs\\MyApp"
   })
   .Build();

using var sdk = OpenTelemetrySdk.Create(builder => builder
   .WithElasticDefaults(config)
   .ConfigureResource(r => r.AddService("MyAppName3"))
   .WithTracing(t => t.AddSource("MyApp.SourceName")));

The preceding code:

1. Defines a constant string variable named edotPrefix to hold the configuration section prefix.
2. Creates a new ConfigurationBuilder to bind configuration values from one or more providers (sources), such as JSON.
3. Calls the AddJsonFile method to read configuration from a JSON file named "appsettings.json".
4. Calls the AddInMemoryCollection method to add configuration settings from a Dictionary of supplied keys and values.
   1. Adds an entry for "SkipInstrumentationAssemblyScanning" prefixed with the correct section name, setting its value to "true."
   2. Adds an entry for "LogDirectory" prefixed with the correct section name, setting its value to "C:\Logs\MyApp".
5. Builds an IConfigurationRoot (castable to IConfiguration) from the provided sources.
6. Passes the IConfiguration from the config variable into the WithElasticDefaults method.

The previous example requires the JSON configuration provider, which you an add as a NuGet package.

<PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="<LATEST>" />

Replace the <LATEST> version placeholder with the latest available package from NuGet.org.