azuremonitorreceiver: The authentication should support Managed Identity.

[martinjt]

Component(s)

receiver/azuremonitor

Is your feature request related to a problem? Please describe.

Currently, there are only manually set Service Principals and Workload Identity (K8s) supported as valid authentication schemes. Since Managed Identity is a core mechanism inside of Azure, that should be a validation option. This would allow for a more seamless experience in Azure Container Apps.

Describe the solution you'd like

In the config for the component you should be able to add "managed_identity" as a valid option.

Describe alternatives you've considered

Providing static credentials via environment variables is an option, however, it's prone to expiry amongst other security issues.

Additional context

Add an additional function here:

https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/azuremonitorreceiver/scraper.go#L86

Update credentials logic here:

https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/azuremonitorreceiver/scraper.go#L179

Update validation here:

https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/azuremonitorreceiver/config.go#L261

Relevant function from the go lib:

https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azidentity#NewManagedIdentityCredential

[github-actions]

Pinging code owners:

• receiver/azuremonitor: @nslaughter @codeboten

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[martinjt]

Fixed in #33584