opentelemetry-dotnet/docs/logs/getting-started

Getting Started with OpenTelemetry .NET Logs 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!

Let's install the packages to get started with logging. If your ConsoleApp targets netcoreapp2.1 install the version 2.1.1 of Microsoft.Extensions.Logging and Microsoft.Extensions.DependencyInjection packages:

dotnet add package Microsoft.Extensions.Logging -v 2.1.1

dotnet add package Microsoft.Extensions.DependencyInjection -v 2.1.1

If your ConsoleApp targets a framework other than netcoreapp2.1, install the latest Microsoft.Extensions.Logging package:

dotnet add package Microsoft.Extensions.Logging

Install the OpenTelemetry.Exporter.Console package (Use the latest version):

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 log output on the console.

LogRecord.TraceId:            00000000000000000000000000000000
LogRecord.SpanId:             0000000000000000
LogRecord.Timestamp:          2020-11-13T23:50:33.5764463Z
LogRecord.EventId:            0
LogRecord.CategoryName:       Program
LogRecord.LogLevel:           Information
LogRecord.TraceFlags:         None
LogRecord.State:              Hello from tomato 2.99.

Congratulations! You are now collecting logs using OpenTelemetry.

What does the above program do?

The program uses the ILogger API to log a formatted string with a severity level of Information. Click here for more information on the different logs levels. Opentelemetry captures this and sends it to ConsoleExporter. ConsoleExporter simply displays it on the console.