opentelemetry-dotnet/docs/metrics/getting-started

Getting Started with OpenTelemetry .NET in 5 Minutes

First, download and install the .NET Core SDK on your computer.

Create a new console application and run it:

dotnet new console --output getting-started
cd getting-started
dotnet run

You should see the following output:

Hello World!

Install the OpenTelemetry.Exporter.Console package:

dotnet add package OpenTelemetry.Exporter.Console

Update the Program.cs file with the code from Program.cs:

Run the application again (using dotnet run) and you should see the metric output from the console, similar to shown below:

Export[] 16:38:36.241 16:38:37.233 TestMeter:counter [tag1=value1;tag2=value2] SumMetricAggregator Value: 590, Details: Delta=True,Mon=True,Count=59,Sum=590
Export[] 16:38:37.233 16:38:38.258 TestMeter:counter [tag1=value1;tag2=value2] SumMetricAggregator Value: 640, Details: Delta=True,Mon=True,Count=64,Sum=640
Export[] 16:38:38.258 16:38:39.261 TestMeter:counter [tag1=value1;tag2=value2] SumMetricAggregator Value: 640, Details: Delta=True,Mon=True,Count=64,Sum=640
Export[] 16:38:39.261 16:38:40.266 TestMeter:counter [tag1=value1;tag2=value2] SumMetricAggregator Value: 630, Details: Delta=True,Mon=True,Count=63,Sum=630
Export[] 16:38:40.266 16:38:41.271 TestMeter:counter [tag1=value1;tag2=value2] SumMetricAggregator Value: 640, Details: Delta=True,Mon=True,Count=64,Sum=640

Congratulations! You are now collecting metrics using OpenTelemetry.

What does the above program do?

The program creates a Meter instance named "TestMeter" and then creates a Counter instrument from it. This counter is used to repeatedly report metric measurements until exited after 10 seconds.

An OpenTelemetry MeterProvider is configured to subscribe to instruments from the Meter TestMeter, and aggregate the measurements in-memory. The pre-aggregated metrics are exported every 1 second to a ConsoleExporter. ConsoleExporter simply displays it on the console.