[FEATURE REQ] Enable AzureSdkLogForwarder in Azure Monitor OTel distro

[lmolkova]

Library name

Azure.Monitor.OpenTelemetry.AspNetCore

Please describe the feature.

Azure SDKs emit logs using EventSources. EventSources can be forwarded to ILogger using AzureEventSourceLogForwarder

Some SDKs like CosmosDB leverage this to emit essential diagnostic information and currently have to ask users to enable it explicitly:

https://github.com/Azure/azure-cosmos-dotnet-v3/blob/8af055c68e01af1df9d530d3b716437c68ee5579/Microsoft.Azure.Cosmos.Samples/Usage/OpenTelemetry/Program.cs#L67-L68

AzMon distro should support Azure SDK logs by default.

[TimothyMothra]

Should this be an opt-in feature?
I'm imagining users would only want this enabled if there's an issue.
Currently we're not sending the Exporter's internal logs to the AI Resource.

[TimothyMothra]

Cijo commented that this sounds like the same feature that was added to the AI SDK:

• "Report internal dependencies from Cosmos SDK as InProc and align with Cosmos SDK EventSource changes"
  Support internal and client spans from cosmos db microsoft/ApplicationInsights-dotnet#2712

Long term, is there a plan for Azure SDKs to migrate to ILogger natively?

[lmolkova]

Long term, is there a plan for Azure SDKs to migrate to ILogger natively?

No, we won't add a dependency on ILogger and we will keep using EventSource to write our logs.
We can however bake in log forwarder into the distro (to avoid adding a dependency).

I'm imagining users would only want this enabled if there's an issue.

Users enable error/warn SDK logs by default because these logs provide observability. Some users enable info logs, some use them instead of traces - these logs are for users.
Verbose logs are mostly for us to debug things - we don't expect users to enable verbose logs from us..

Opt-in mechanism is already part of ILogger, but the distro should allow opt-in to happen.

[jcocchi]

+1, the user should still be able to control their own log level/ sampling. The ask is for the capability for logging to wired up by default