Helm 3: diff looks like .Capabilities.APIVersions.Has always false

[jkroepke]

I have some conditions on my chart for check apis installed on the kubernetes server like

{{ if .Capabilities.APIVersions.Has "image.openshift.io/v1" }}

While on helm 2 the condition correctly evalutated it looks like on helm 3 the condition is always false.

The reason is the diff output is wrong because all code inside the if is marked as removed.

Using 3.0.0-rc.7 of helm-diff

[pkalemba]

+1
I have the same problem for stable/prometheus-operator and stable/filebeat
Looks like it has problem with CRD only.

[databus23]

Yeah, the problem is that helm template is not talking to the apiserver, it has the default apis harcoded. It also always reports 1.16. as its version: https://github.com/helm/helm/blob/2f4ef705a9e8ea0e38a2c99c29c5e4de59b03d75/pkg/chartutil/capabilities.go#L30-L37

This might be solved by using --validate which helm diff is not using at the moment. Last time I checked --validate would fail if resources where already present in the cluster. This might have changed. In general for a more correct diff output we would need helm template to have the actual capabilities of the cluster loaded.

[databus23]

Yeah, so rendering the chart with helm template --validate would give us a correct .Capabilites but at the moment this will break because of this: helm/helm#6663

I think we need to create an upstream issue and discuss how this could be solved. I think it would be helpful if helm template could skip the exitingResource check. But it seems this requires some discussions with the maintainers: helm/helm#6663 (comment)

As it stands helm-diff can't properly render charts that make use of .Capabilities which I would like to fix.

/cc @thomastaylor312

[thomastaylor312]

Hey @databus23! Just catching up on things after a bunch of vacation. So is the main problem around not having the proper api versions available in the .Capabilities? Is it something beyond using the --api-versions flag?

[jkroepke]

Instead using helm template internally is helm upgrade --dry-run a valid option?