Helm Construct dynamic configmap from multiple configuration YAML file

Question

I have 2 files as follows:

_config-dev.yaml

frontend:
  NODE_ENV: dev
  REACT_APP_API_URL: 'https://my-dev-apiurl/'

database:
  DB_USER: admin-dev
  DB_PASSWORD: password-dev
  

_config-stag.yaml

frontend:
  NODE_ENV: stag
  REACT_APP_API_URL: 'https://my-stag-api-url/'

database:
  DB_USER: admin-stag
  DB_PASSWORD: password-stag

myConfigMap.yaml

kind: ConfigMap
apiVersion: v1
metadata:
  name: {{ .Release.Name }}-frontend
  namespace: {{ .Values.global.namespace }}
data:
  # Here I want to insert only frontend data from _config-dev.yaml file if my {{ eq .Values.global.environment "dev" }} like below
  NODE_ENV: dev
  REACT_APP_API_URL: 'https://my-dev-apiurl/'

  # if my {{ eq .Values.global.environment "stag" }} i want to get frontend values from _config-dev.yaml like below
  NODE_ENV: stag
  REACT_APP_API_URL: 'https://my-stag-api-url/'

Can anyone figure out how to insert the data as per above scenario mentioned in myConfigMap.yaml file as a comment under data:.

Answer 1

my test project

test
├── Chart.yaml
├── cfg
│   ├── _config-dev.yaml
│   └── _config-stag.yaml
├── templates
│   └── configmap.yaml
└── values.yaml

values.yaml

global:
  environment: dev

test/cfg/_config-dev.yaml

frontend:
  NODE_ENV: dev
  REACT_APP_API_URL: 'https://my-dev-apiurl/'

database:
  DB_USER: admin-dev
  DB_PASSWORD: password-dev

test/cfg/_config-stag.yaml

frontend:
  NODE_ENV: stag
  REACT_APP_API_URL: 'https://my-stag-api-url/'

database:
  DB_USER: admin-stag
  DB_PASSWORD: password-stag

test/templates/configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ include "test.fullname" . }}
data:
  {{- $data := .Files.Get "cfg/_config-stag.yaml" }}
  {{- if eq .Values.global.environment "dev" }}
  {{- $data = .Files.Get "cfg/_config-dev.yaml" }}
  {{- end }}
  {{- $cfg := fromYaml $data }}
  {{- range $k, $v := $cfg.frontend }}
  {{ $k }}: {{ $v }}
  {{- end }}

output

apiVersion: v1
kind: ConfigMap
metadata:
  name: test
data:
  NODE_ENV: dev
  REACT_APP_API_URL: https://my-dev-api-url/