Getting container metadata from another project

[afscrome]

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

It would be helpful if you could get container build information from for one project from another project:

For CLI based apps, you can get this information out via -getproperty and -getitem but there's no way to do this within a larger msbuild project.

Describe the solution you'd like

A target that can output the following information in a way that can be read in another project

• Whether the project is enabled for SDK container builds
• Container Registry
• Container Repository
• Container Tags
• Container Ports (including derivations from ASPNETCORE_URLS, ASPNETCORE_HTTP_PORTS & ASPNETCORE_HTTPS_PORTS

Additional context

For context of what I'm looking for - I'm trying to capture container metadata from an application in a library that can reference that project's container as a custom Aspire Hosting Integration, using a similar pattern to Aspire's IProjectMetadata implementation:

https://github.com/afscrome/AspireProjectAsContainerNugetIntegration/blob/eea83ae7270d5f55425a4a448c4d7d0570e09363/SdkContainerPackage.Aspire.Hosting.ApiService/sdk/Sdk.targets#L38-L49
https://github.com/afscrome/AspireProjectAsContainerNugetIntegration/blob/eea83ae7270d5f55425a4a448c4d7d0570e09363/Directory.Build.targets#L3-L12

[baronfel]

triage: this makes total sense to do - we should be able to return/output an Item or Items that provide access to this information to an external caller. We'd happily accept a PR here - though as you said in chat you might want to wait until #49556 clears to prevent churn. I think this would be pretty straightforward to do correctly, though - so if you wanted to send a PR and we merged it, it would be my problem to integrate with (and presumably keep tests green 😄 )