Support Helm3 OCI Charts

[crossplane-contrib]

Support Helm3 OCI Charts

[ferhatying]

OCI integration is moving from experimental to full feature. See also helm/helm#10393. It's currently part of v3.8.0-rc.1.

[benagricola]

It seems this was implemented as part of v3.5.0: helm/helm@3ad08f3

Having a bit of brainfail reading this today, but as far as I can tell this leaves the actual RegistryClient internal and just adds the experimental implementation into the existing helm pull command, and the switch between v2 and OCI based charts just involves detecting oci:// chart URLs and setting client.OCI = true.

If I'm understanding correctly, this should mean we just need to do the same detection in provider-helm and build against helm 3.5.0.

@janwillies does this match your understanding? I'll sort out a PR if so.

e: Actually, after having a more in-depth look, I think this still isn't possible, as registryClient is still internal and is not automatically instantiated onto actionConfig 😞

[benagricola]

From an implementation perspective this looks pretty simple, but the V2 pull action is broken down into a couple of separate steps when using OCI images, these are:

• NewRegistryLogin: Login to the registry at Repository using Username and Password
• NewChartPull: Pull OCI Chart Ref from registry into local container cache. This requires a combination of Name and Version (or new Ref field?)
• NewChartExport: Export OCI Chart from local container cache to a file. Again based on a Ref field or combination of Name and Version.

The only problem with actually doing this is that the ActionConfig.Init method (from helm) doesn't automatically add a RegistryClient instance - and the RegistryClient instantiation code (usage here) in helm is still marked internal so I suspect this needs to wait until that code is made available externally. All comments I can find suggest that was planned for V3.3 or V3.4 but I don't see any change in either of those versions 🕐

[janwillies]

It seems this was implemented as part of v3.5.0: helm/helm@3ad08f3

[benagricola]

helm/helm/issues/9188 - looks like moving registry out of internal is on the roadmap but no solid timescale yet, guess we just have to wait and see 🙂

[echarles]

+1 to get this feature

[benagricola]

Updates on the helm issue above seem to suggest the registryClient will be available in Helm 3.7 or 3.8 so we'll need to wait for those releases before implementing.

[ferhatying]

Update: OCI support is now GA in Helm v3.8.0. It's not experimental anymore.