Pulumi dry runs don't actually produce a preview

[ryanjjung]

I thought the automation would log it out to the configured files, but it doesn't appear to. You only get an extremely basic summary that is not very informative.

[ryanjjung]

Looks like the various execution commands support some output options like on_output and on_error that accept functions as arguments. Those functions deal with the output however they need. Refs:

• https://www.pulumi.com/docs/reference/pkg/python/pulumi/#pulumi.automation.Stack.preview
• https://github.com/pulumi/automation-api-examples/blob/main/python/inline_program/main.py#L87