How to evaluate helmv3 printf output as jinja expression - helm3

Question

Based on number of nodes, I need to refer the certificate and key from yaml file.
{{- $root := . -}}
{{ range $k, $v := until (int ($root.Values.data.nodeCount) ) }}
apiVersion: v1
kind: Secret
metadata:
name: {{ $root.Values.clusterName }}-nodes-{{$k}}-secret
type: Opaque
data:
crt: {{ printf "$root.Values.data.node_%d_key" $k }}
---
{{- end }}
Example output: It doesn't show the output value it only shows the printf output which is string, how can I evaluate the printf output to get the evaultation to retrieve result from values.yaml
---
apiVersion: v1
kind: Secret
metadata:
name: test-nodes-0-secret
type: Opaque
data:
crt: $root.Values.data.node_0_key
---
apiVersion: v1
kind: Secret
metadata:
name: test-nodes-1-secret
type: Opaque
data:
crt: $root.Values.data.node_1_key
example values.yml
nodeCount: 3
clusterName: "test"
data:
nodeCount: 2
node_0_crt: "test"
node_0_key: "test"
node_1_crt: "test1"
node_1_key: "test1"

Answer 1

Note that Helm doesn't use Jinja templating syntax. If you were to try using a Jinja expression in a Helm template it wouldn't work. Helm uses Go templates (with a bunch of custom functions).
For the behavior you want, I think you're looking for the tpl function, which lets you evaluate a string as a Helm template. That might look like this:
{{ range until (int $.Values.data.nodeCount) }}
apiVersion: v1
kind: Secret
metadata:
name: {{ $.Values.clusterName }}-nodes-{{.}}-secret
type: Opaque
data:
crt: {{ tpl (printf "{{ .Values.data.node_%d_key }}" .) $ }}
---
{{- end }}
Note that I've also removed your use of $root; you can just refer to the $ variable if you need to explicitly refer to the root context. I've also slightly simplified the outer range loop.
Given the above template and your sample data, I get the following output:
---
# Source: example/templates/secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: test-nodes-0-secret
type: Opaque
data:
crt: test
---
# Source: example/templates/secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: test-nodes-1-secret
type: Opaque
data:
crt: test1