Change PublisherOptions - Allow skipping image building?

[prom3theu5]

Update property access to use PublisherOptions directly for consistency. Introduce a new option to control image building during the publishing process. Ensure that image building only occurs when enabled. Adjust tests to accommodate these changes.

Just thinking a user probably wouldn't want to rebuild and re-version all project container images if they were simply changing and publishing a new compose for container resource changes (new env vars, new tags etc).

Fixes #8782

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
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      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
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  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
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• Does the change require an update in our Aspire docs?
  • Yes
    • Is this introducing a breaking change?
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        • Link to aspire-docs issue (please use this breaking-change template):
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        • Link to aspire-docs issue (please use this doc-idea template):
  • No

[Copilot]

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

src/Aspire.Hosting.Docker/DockerComposePublishingContext.cs:120

• Consider adding a unit test to verify that the .env file is created and populated with the expected environment variables.

var envFile = Path.Combine(PublisherOptions.OutputPath!, ".env");

[davidfowl]

Should negate this bool here?

[prom3theu5]

Have it default false and explicit opt in to builds?

[davidfowl]

I'm not sure we have a way to flow command line arguments from the publisher, so this needs to be configured in code (I believe).

@mitchdenny ?

[prom3theu5]

A clean win without polluting cli could be to handle extra publisher options from IConfiguration and the AppHosts AppSettings?
Then just utilise the configuration binder Get extension to populate an instance of "Optional" config, and "Merge" that onto the incoming (from cli) Publisher Options?
Maybe a small source generator to generate a MergeExtension, for each PublisherSettings derived instance?

[prom3theu5]

To be fair, could just be manually assigned, without the MergeExtension - we're only talking about a handful of options for each publisher - The helm one has more that Compose, and will potentially require even more for extension

I guess another option would be a new ManifestExpression, and have config directly in the AppHost declaratively

[mitchdenny]

We didn't get to mapping switches to config in 9.2 but as you've alluded the plan is to make use of IConfiguration. When registering publishers I'll probably have an optional mapping mechanism from switches to config sections.