Using https://golang.org/pkg/text/template/, I sometimes need to use variables in the accessed path (for kubernetes deployments).
I end up writing something like :
{{ if (eq .Values.cluster "aws" }}{{ .Values.redis.aws.masterHost | quote }}{{else}}{{ .Values.redis.gcp.masterHost | quote }}{{end}}What I'd really like to write is pretty much {{ .Values.redis.{{.Values.cluster}}.masterHost | quote }} , which doesn't compile.
Is there a way to write something similar ? (so having a kind of variable in the accessed path).
You can use _helpers.tpl file to define logic and operate with values.
_helpers.tpl
{{/*
Get redis host based on cluster.
*/}}
{{- define "chart.getRedis" -}}
{{- if eq .Values.cluster "aws" -}}
{{- .Values.redis.aws.masterHost | quote -}}
{{- else -}}
{{- .Values.redis.gcp.masterHost | quote -}}
{{- end -}}
{{- end -}}values.yaml
cluster: local
redis:
aws:
masterHost: "my-aws-host"
gcp:
masterHost: "my-gcp-host"And use it in your Deployment (here's a ConfigMap example to keep it shorter)
configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: Configmap
data:
redis: {{ template "chart.getRedis" . }}Output:
helm install --dry-run --debug mychart
[debug] Created tunnel using local port: '64712'
...
COMPUTED VALUES:
cluster: local
redis:
aws:
masterHost: my-aws-host
gcp:
masterHost: my-gcp-host
HOOKS:
MANIFEST:
---
# Source: mychart/templates/configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: Configmap
data:
redis: "my-gcp-host"Set cluster value to aws:
helm install --dry-run --debug mychart --set-string=cluster=aws
[debug] Created tunnel using local port: '64712'
...
COMPUTED VALUES:
cluster: local
redis:
aws:
masterHost: my-aws-host
gcp:
masterHost: my-gcp-host
HOOKS:
MANIFEST:
---
# Source: mychart/templates/configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: Configmap
data:
redis: "my-aws-host"