[QUERY] Azure.Monitor.OpenTelemetry.AspNetCore - How to write custom dimensions with ILogger?

[Leonardo-Ferreira]

Library name and version

Azure.Monitor.OpenTelemetry.AspNetCore 1.3.0-beta.2

Query/Question

using Azure.Monitor.OpenTelemetry.AspNetCore as a "sink" and ILogger, how can I write a log with a custom dimension that will show for that log alone? I don't want the custom dimension to reflect for the all the logs/dependencies/metrics of a given request... just like the classical LogTelemetry.CustomDimensions.Add("specificDimensionA", "value A") ?

Environment

.net 9, latest version
other packages:
OpenTelemetry.Exporter.Console
OpenTelemetry.Extensions.Hosting
OpenTelemetry.Instrumentation.AspNetCore

[cidico]

I've being trying to do this as well.
Let me know if you find a solution!

[github-actions]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @rajkumar-rangaraj @TimothyMothra.

[AugustoNeves]

I would also like to know the answer to this question.

[gastonmuijtjens]

Hi @Leonardo-Ferreira @cidico @AugustoNeves,

While perhaps not ideal, one possibility would be to wrap the log statement inside a logging scope that sets tags: https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/docs/logs/customizing-the-sdk/README.md#includescopes

See also this example: https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/docs/logs/customizing-the-sdk/Program.cs. You should set IncludeScopes to true to make this work.

According to the source code, the Azure Monitor Exporter exports those logging scopes to custom dimensions in Application Insights:

azure-sdk-for-net/sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/Internals/LogsHelper.cs

Line 25 in 91af14e

foreach (KeyValuePair<string, object?> scopeItem in scope)

[PraveenVerma17]

@gastonmuijtjens
It's not ideal because it adds many other properties from different scopes. For example, in HTTP requests, it logs all HTTP scope tags in custom dimensions.

The worst part is that Azure.Monitor.OpenTelemetry.AspNetCore does not honor predefined tags. For instance, client.address, user.id, etc., all go to custom dimensions. I'm not sure if Azure.Monitor.OpenTelemetry.AspNetCore has any plans to provide an option to override predefined tags in middleware.