helm_release manifest is null

[PAKalucki]

Terraform, Provider, Kubernetes and Helm Versions

Terraform version: 1.10.4
Provider version: 2.17.0

Affected Resource(s)

• helm_release

Terraform Configuration Files

resource "helm_release" "external_nginx_ingress" {
  name = "external-ingress-nginx"

  repository       = "https://kubernetes.github.io/ingress-nginx"
  chart            = "ingress-nginx"
  version          = "4.11.3"
  namespace        = "default"
  create_namespace = true
}

output "nginx_manifest_tmp" {
  value = "test : ${helm_release.external_nginx_ingress.manifest}"
}

Debug Output

Panic Output

Steps to Reproduce

1. terraform apply

Expected Behavior

According to documentation it should output manifest (String) The rendered manifest as JSON.

Actual Behavior

│ Error: Invalid template interpolation value
│
│   on outputs.tf line 6, in output "nginx_manifest_tmp":
│    6:   value = "test : ${helm_release.external_nginx_ingress.manifest}"
│     ├────────────────
│     │ helm_release.external_nginx_ingress.manifest is null
│
│ The expression result is null. Cannot include a null value in a string template.

[madduci]

I have the same issue, also by tofu test.

[mkielar]

Hit the same when deploying Istio through Terraform and Helm Charts. I'd like to fetch the helm-generated name of the Istio Controller Service to pass it to TargetGroupBinging when attaching it to external ALB. Parsing the manifest seems like a no-brainer, but it doesn't work 😞.

[mkielar]

OK, I found this:

• https://registry.terraform.io/providers/hashicorp/helm/latest/docs#experiments
• https://github.com/hashicorp/terraform-provider-helm/blob/main/helm/resource_helm_release.go#L1389-L1401

Looks like this is now just an experiment and not a stable functionality, and the return attribute is just not described informatively enough in the documentation.

I've enabled this experiment, and two things happened:

1. terraform plan shows entire manifest that helm generates (and there's a lot of that if you deploy charts like istio-gateway ;-)).
2. You can reference the manifest attribute and get a lot of text :)