Automatically generate .env variables for HarperDB connection.

genereate_hdb_env.js

const fs = require("fs");

fs.readFile("./install_log.log", (err, data) => {
  if (err) throw err;
  const s = data.toString();

  // prettier-ignore
  const regex_ports = /HTTPS?_PORT\\\"\:\\\"(\d+)/g;

  let port_match = regex_ports.exec(s);
  const http_port = port_match[1]
  port_match = regex_ports.exec(s);
  const https_port = port_match[1];

  // prettier-ignore
  const regex_creds = /HDB_ADMIN_\w+\\\":\\\"([^:]+(?=\\\"(?:,|})))/g;
  
  let cred_match = regex_creds.exec(s);
  const username = cred_match[1];
  cred_match = regex_creds.exec(s);
  const password = cred_match[1];

  if (username === undefined 
    || password === undefined 
    || http_port === undefined 
    || https_port === undefined )
    throw new Error("Error reading log file. Please add .env manually.");

  const envVars =
    `HDB_HTTP_PORT=${http_port}\nHDB_HTTPS_PORT=${https_port}\nHDB_USERNAME=${username}\nHDB_PASSWORD=${password}`;

  fs.writeFile(".env", envVars, err => {
    if (err) throw err;
    console.log("The file has been saved!");
    console.log(`envVars: \n${envVars}`);
  });
});