Helm yaml keys from values.yaml - yaml

Question

I want to make a yaml KEY (not the value) dynamically.
In my values.yaml
failoverip1: 0.0.0.0` (<- this is only a demo IP)
In my templates/configmap.yaml I have this:
apiVersion: v1
kind: ConfigMap
metadata:
name: vip-configmap
data:
{{- .Values.failoverip1 -}}: {{ .Release.Namespace -}}/{{- .Values.target -}}
^^^^^^^^^^^^^^^^^^^^^----> here should be an IP address from values.yaml
{{ .Release.Namespace -}}/{{- .Values.target -}} renders successfully.
But if I add {{- .Values.failoverip1 -}} to the key part, it renders nothing.
(Nothing means, the whole data: block, does not get rendered.
This is the error message when I run helm install --name hetzner-failover .
Error: YAML parse error on hetzner-failover/templates/configmap-ip.yaml: error converting YAML to JSON: yaml: line 4: mapping values are not allowed in this context
Is it not allowed to make a
key dynamic?
If not, how to drive around that?
Here is the repo I am talking of:
https://github.com/exocode/helm-charts/blob/master/hetzner-failover/templates/configmap-ip.yaml

Answer 1

The error seems to be, that the leading - got cut.
So the correct way is to remove that minus:
Before:
{{- .Values.failoverip1 | indent 2 -}}
After:
{{ .Values.failoverip1 | indent 2 -}}
The yaml is now:
apiVersion: v1
kind: ConfigMap
metadata:
name: vip-configmap
data:
{{ .Values.failoverip1 | indent 2 -}}: {{ .Release.Namespace -}}/{{- .Values.target -}} # add your config map here. must map the base64 encoded IP in secrets.yaml
And the rendered result is:
kubectl get configmap -o yaml
apiVersion: v1
items:
- apiVersion: v1
data:
0.0.0.0: default/nginx# add your config map here. must map the base64 encoded
IP in secrets.yaml
kind: ConfigMap