First, download and install the .NET SDK on your computer.
Create a new web application:
dotnet new web -o aspnetcoreapp
cd aspnetcoreapp
Install the OpenTelemetry.Exporter.Console, OpenTelemetry.Extensions.Hosting, and OpenTelemetry.Instrumentation.AspNetCore packages:
dotnet add package OpenTelemetry.Exporter.Console
dotnet add package OpenTelemetry.Extensions.Hosting
dotnet add package OpenTelemetry.Instrumentation.AspNetCore
Update the Program.cs
file with the code from Program.cs.
Run the application again (using dotnet run
) and then browse to the url shown
in the console for your application (ex http://localhost:5154
). You should see
the metrics output from the console.
Export http.server.duration, Measures the duration of inbound HTTP requests., Unit: ms, Meter: OpenTelemetry.Instrumentation.AspNetCore/1.0.0.0
(2023-04-11T21:49:43.6915232Z, 2023-04-11T21:50:50.6564690Z] http.flavor: 1.1 http.method: GET http.route: / http.scheme: http http.status_code: 200 net.host.name: localhost net.host.port: 5000 Histogram
Value: Sum: 3.5967 Count: 11 Min: 0.073 Max: 2.5539
(-Infinity,0]:0
(0,5]:11
(5,10]:0
(10,25]:0
(25,50]:0
(50,75]:0
(75,100]:0
(100,250]:0
(250,500]:0
(500,750]:0
(750,1000]:0
(1000,2500]:0
(2500,5000]:0
(5000,7500]:0
(7500,10000]:0
(10000,+Infinity]:0
Congratulations! You are now collecting metrics using OpenTelemetry.
What does the above program do?
The program uses the OpenTelemetry.Instrumentation.AspNetCore package to automatically create metrics for incoming ASP.NET Core requests, uses the OpenTelemetry.Exporter.Console package to write metrics to the console every 1000 milliseconds. This is done by configuring an OpenTelemetry MeterProvider using extension methods and setting it to auto-start when the host is started:
appBuilder.Services.AddOpenTelemetry()
.ConfigureResource(builder => builder
.AddService(serviceName: "OTel.NET Getting Started"))
.WithMetrics(builder => builder
.AddAspNetCoreInstrumentation()
.AddConsoleExporter((exporterOptions, metricReaderOptions) =>
{
metricReaderOptions.PeriodicExportingMetricReaderOptions.ExportIntervalMilliseconds = 1000;
})
);
Note
The AddOpenTelemetry
extension is part of the
OpenTelemetry.Extensions.Hosting
package.
The index route ("/") is set up to write out a greeting message on the response:
app.MapGet("/", () => $"Hello from OpenTelemetry Metrics!");