[BOP-951] Introduce dependencies for helm chart addons

[byDimasik]

Description

Allow specifying dependencies for helm chart addons. FluxCD supports dependencies and asks for the name and the namespace of the HelmRelease. In BOP, we create the HelmRelease objects, so, in the blueprint, it's enough to specify the addon name without the need to set a namespace which is always blueprint-system.

Testing

Deployed MKE Dashboard addon with nginx as in the dependencies, the blueprint looked like this

    - chart:
        dependsOn:
        - nginx
        name: mke-dashboard-chart
        repo: oci://ghcr.io/mirantiscontainers

The resulting HelmRelease

% kb get helmrelease ui -oyaml
apiVersion: helm.toolkit.fluxcd.io/v2
kind: HelmRelease
metadata:
  <...>
spec:
  chart:
    <...>
  dependsOn:
  - name: nginx
    namespace: blueprint-system

[ranyodh]

Should be of type NamespacedObjectReference so we can depend on a addon from another namespace?

[byDimasik]

@ranyodh

Nope, FluxCD needs the HelmRelease name and namespace. BOP generates all helm releases with the following values:

&helmv2.HelmRelease{
    ObjectMeta: metav1.ObjectMeta{
        Name:      addon.Spec.Name,
        Namespace: consts.NamespaceBoundlessSystem,
    },
},

here the namespace is always blueprint-system, and the release name is the addon name, so, all we need to allow dependencies between addons is the addon name.

[nwneisen]

Just one thought