application.yml with configmap data

README.md

• for local development
• read env config from configmap data section
• replace application.yml with configmap data

application.yml

server:
    port: ${SERVER_PORT}
database:
    host: ${DB_HOST}
    name: ${DB_NAME}
    username: ${DB_USER}
    password_secret: ${DB_PASS_SECRET}

configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  creationTimestamp: 2022-02-18T18:52:05Z
  name: game-config
  namespace: default
  resourceVersion: "516"
  uid: b4952dc3-d670-11e5-8cd0-68f728db1985
data:
  SERVER_PORT: 8080
  DB_HOST: localhost
  DB_NAME: management
  DB_USER: postgres
  DB_PASS_SECRET: /run/secret/postgressecret

index.js

'use strict';

const fs = require('fs');
const path = require('path');
const yaml = require('js-yaml');

try {
    // Synchronicity used only for the example (it stops the Event Loop). 
    const data = fs.readFileSync('configmap.yaml', 'utf8');
    const parsedData = yaml.load(data);
    /*
      {
      SERVER_PORT: 8080,
      DB_HOST: 'localhost',
      DB_USER: 'postgres',
      DB_PASS_SECRET: '/run/secret/postgressecret'
      }
    */
    // console.log(parsedData.data);

    let template = fs.readFileSync(path.join(__dirname, "application.yml"), 'utf8', (err) => {
        if (err) return console.log(err);
    });

    template = template.replace(/\${([^{}]+)}/g, (keyExpr, key) => {
        return parsedData.data[key] || "";
    });

    console.log(template);
    fs.writeFile("application_target.yml", template, 'utf8', (err) => {
        if (err) return console.log(err);
    });
} catch (e) {
    console.log(e);
}