Add flag to include/exclude components by namespace

[hooten]

Feature request

Add flag to include/exclude components that evaluate to a given namespace. For example:

qbec apply k8s-cluster -n namespaceA

would only apply k8s resources that have namespace: namespaceA. A similar command with a -N flag could exclude k8s resources with the given namespace.

This feature would be similar to the component or kind flags, which are as follows:

-c, --component stringArray           include just this component
-C, --exclude-component stringArray   exclude this component
-k, --kind stringArray                include objects with this kind
-K, --exclude-kind stringArray        exclude objects with this kind

This feature would not be applicable for cluster-scoped resources. In the case that there are cluster-scoped resources in the repo and and include/exclude namespace flag is specified, I would expect no cluster resources to be returned.

Use case

I have a mono-repo that deploys to k8s resources to multiple namespaces, but I would like to create separate jobs for each namespace in order to limit deployment permissions and blast radius for each job.

[gotwarlost]

• First off, we cannot use -n since that is already a global flag for --dry-run. We probably need to pick -p and -P for include and exclude
• What are the semantics for cluster scoped objects when this flag is present? I guess you are saying they are filtered out, which is fine I think.
• What happens when an object is "moved" in source code from one existing namespace to another? I guess that will be treated as an "add" in one and a "delete" in the other. We need to ensure this happens correctly.
• Do we want to treat a namespace object which is cluster-scoped differently for this operation. As in, consider the namespace object with the matching name as a candidate for add/update? I think intuitively it makes sense to do this but it is also fair to leave it out in the first pass and add it later if needed.

[hooten]

• The -p/-P flags are fine.
• Yes, I think cluster-scoped objects should be filtered out because they do not have a namespace.
• Yes, I agree with your comments on "moving" an object.
• I can see both sides for namespace objects. I am fine with whatever approach you prefer here.

[gotwarlost]

Let's leave the namespace object out of it. We can add it later if needed