Helm Error: parse error at invalid syntax - kubernetes-helm

Question

How can I escape () in helm template… I tried as below but getting Error: parse error at yaml:17): invalid syntax..
At the end I need this output "{{ (index . "demo-app-secret") | b64dec }}"
Here is the yaml.
{{- range $externalSecretName, $externalSecret := .Values.externalSecrets }}
apiVersion: external-secrets.io/v1beta1
kind: ExternalSecret
metadata:
name: {{ $.Release.Name }}
spec:
refreshInterval: 10m
secretStoreRef:
name: tf-address-handling-fortanix
kind: SecretStore
target:
name: {{ $.Release.Name }}
creationPolicy: Owner
template:
data:
{{- range $externalSecret.data }}
{{ .secretKey }}: "{{ printf "{{ \(index . \"%s\"\) | b64dec }}" .secretKey }}"
{{- end }}
data:
{{- toYaml $externalSecret.data | nindent 4 }}
{{- end }}
Here is the values.yaml
externalSecrets:
master-tf-address-handling:
data:
- secretKey: xxxxxxxx
remoteRef:
key: xxxxx
- secretKey: yyyy
remoteRef:
key: yyyyy

Answer 1

The parentheses don't need to be escaped at all, and if you remove the backslash escaping before the parentheses then you'll get the output you expect.
{{ .secretKey }}: "{{ printf "{{ (index . \"%s\") | b64dec }}" .secretKey }}"
{{/* ^ ^
no backslashes */}}
If you run this through helm template, you'll get a second error. The output string you get has unescaped double-quotes inside a double-quoted string
xxxxxxxx: "{{ (index . "xxxxxxxx") | b64dec }}"
# ^ ^ ^ ^
# too many double quotes
To fix this you need extra backslashes in the output
xxxxxxxx: "{{ (index . \"xxxxxxxx\") | b64dec }}"
# ^ ^
# add these backslashes
and to get that you need an additional double backslash inside the template
{{ .secretKey }}: "{{ printf "{{ (index . \\\"%s\\\") | b64dec }}" .secretKey }}"
{{/* ^^ ^^
add these backslashes */}}