Multiline string inside a chart value - yaml

Question

I am trying to create a helm chart. Inside the deployment folder I have a configmap template that looks like this:
apiVersion: v1
kind: ConfigMap
metadata:
name: config
data:
app-properties: |
{{ .Values.app.appProperties }}
My default values have this:
app:
appProperties: |
line1
That code appears to work, but I need more lines in app.appProperties and the moment I add more lines there like this:
app:
appProperties: |
line1
line2
line3
I get:
upgrade.go:142: [debug] preparing upgrade for myhelm
Error: UPGRADE FAILED: YAML parse error on helm/templates/cms.yml: error converting YAML to JSON: yaml: line 11: could not find expected ':'
helm.go:84: [debug] error converting YAML to JSON: yaml: line 11: could not find expected ':'
YAML parse error on helm/templates/cms.yml
The templated definition I was expecting should be:
apiVersion: v1
kind: ConfigMap
metadata:
name: config
data:
app-properties: |
line1
line2
line3
What's the right way to do that ?

Answer 1

The reason here is mostly because of the incorrect indentation which you can verify by running helm template with --debug flag. You could either use only nindent 4 with your values as that seems to be the correct indentation level or also use tpl if the multiline string has some templates inside which you want to move in the config map.
{{- /*
ConfigMap template
*/ -}}
apiVersion: v1
kind: ConfigMap
metadata:
name: config
data:
app-properties:
{{- .Values.app.appProperties | nindent 4 }}
---
## Values File
app:
appProperties: |
line1
line2
line3
Result
➜ $ helm template ./
---
# Source: my-local-functions/templates/multi-line-string.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: config
data:
app-properties:
line1
line2
line3
Example with tpl function
{{- /*
In the templates directory somefile.yaml
*/ -}}
multiLineString:
{{- tpl .Values.multiLine . | nindent 2 }}
---
## Values Files
extraFruits: banana
multiLine: |
I am a line
{{ .Values.extraFruits }}
Result:
➜ $ helm template ./
---
# Source: my-local-functions/templates/somefile.yaml
multiLineString:
I am a line
banana
Hope this helps.