Resources
A resource represents the entity producing telemetry as resource attributes. For example, a process producing telemetry that is running in a container on Kubernetes has a Pod name, a namespace, and possibly a deployment name. All three of these attributes can be included in the resource.
In your observability backend, you can use resource information to better investigate interesting behavior. For example, if your trace or metrics data indicate latency in your system, you can narrow it down to a specific container, pod, or kubernetes deployment.
Setup
Follow the instructions in the Getting Started, so that you have a running .NET app exporting data to the console.
Adding resources with environment variables
You can use the OTEL_RESOURCE_ATTRIBUTES environment variable to inject
resources into your application. The .NET SDK will automatically detect these
resources.
The following example adds Service, Host and OS resource attributes
via environment variables, running unix programs like uname to generate the
resource data.
env OTEL_RESOURCE_ATTRIBUTES="service.name=resource-tutorial-dotnet,service.namespace=tutorial,service.version=1.0,service.instance.id=`uuidgen`,host.name=`HOSTNAME`,host.type=`uname -m`,os.name=`uname -s`,os.version=`uname -r`" dotnet run
Activity.TraceId: d1cbb7787440cc95b325835cb2ff8018
Activity.SpanId: 2ca007300fcb3068
Activity.TraceFlags: Recorded
Activity.ActivitySourceName: tutorial-dotnet
Activity.DisplayName: SayHello
Activity.Kind: Internal
Activity.StartTime: 2022-10-02T13:31:12.0175090Z
Activity.Duration: 00:00:00.0003920
Activity.Tags:
foo: 1
bar: Hello, World!
baz: [1,2,3]
Resource associated with Activity:
service.name: resource-tutorial-dotnet
service.namespace: tutorial
service.version: 1.0
service.instance.id: 93B14BAD-813D-48EE-9FB1-2ADFD07C5E78
host.name: myhost
host.type: arm64
os.name: Darwin
os.version: 21.6.0
Adding resources in code
You can also add custom resources in code by attaching them to a
ResourceBuilder.
The following example builds on the getting started sample and adds two custom
resources, environment.name and team.name in code:
using System.Diagnostics;
using System.Collections.Generic;
using OpenTelemetry;
using OpenTelemetry.Trace;
using OpenTelemetry.Resources;
var serviceName = "resource-tutorial-dotnet";
var serviceVersion = "1.0";
var resourceBuilder =
ResourceBuilder
.CreateDefault()
.AddService(serviceName: serviceName, serviceVersion: serviceVersion)
.AddAttributes(new Dictionary<string, object>
{
["environment.name"] = "production",
["team.name"] = "backend"
});
var sourceName = "tutorial-dotnet";
using var tracerProvider = Sdk.CreateTracerProviderBuilder()
.AddSource(sourceName)
.SetResourceBuilder(resourceBuilder)
.AddConsoleExporter()
.Build();
var MyActivitySource = new ActivitySource(sourceName);
using var activity = MyActivitySource.StartActivity("SayHello");
activity?.SetTag("foo", 1);
activity?.SetTag("bar", "Hello, World!");
activity?.SetTag("baz", new int[] { 1, 2, 3 });
In this example, the service.name and service.version values are
set in code as well. Additionally, service.instance.id gets a
default value.
If you run the same command as in Adding resources with environment
variables, but this time
without service.name service.version, and service.instance.id,
you’ll see the environment.name and team.name resources in the resource list:
env OTEL_RESOURCE_ATTRIBUTES="service.namespace=tutorial,host.name=`HOSTNAME`,host.type=`uname -m`,os.name=`uname -s`,os.version=`uname -r`" dotnet run
Activity.TraceId: d1cbb7787440cc95b325835cb2ff8018
Activity.SpanId: 2ca007300fcb3068
Activity.TraceFlags: Recorded
Activity.ActivitySourceName: tutorial-dotnet
Activity.DisplayName: SayHello
Activity.Kind: Internal
Activity.StartTime: 2022-10-02T13:31:12.0175090Z
Activity.Duration: 00:00:00.0003920
Activity.Tags:
foo: 1
bar: Hello, World!
baz: [1,2,3]
Resource associated with Activity:
environment.name: production
team.name: backend
service.name: resource-tutorial-dotnet
service.namespace: tutorial
service.version: 1.0
service.instance.id: 28976A1C-BF02-43CA-BAE0-6E0564431462
host.name: pcarter
host.type: arm64
os.name: Darwin
os.version: 21.6.0
Note: If you set resource attributes with both environment variables and code, the values in code take precedence.
Next steps
There are more resource detectors you can add to your configuration, for example to get details about your Cloud environment or Deployment.