prerun.mjs

import fs from 'fs';
import { findUp } from 'find-up';
import * as Dotenv from 'dotenv';
import yargs from 'yargs';
import { hideBin } from 'yargs/helpers';

const requiredEnvKeys = ['DOGU_RUN_TYPE', 'NEXT_PUBLIC_ENV'];

async function parseDotenv() {
  const envFilePath = await findUp(`.env`);
  if (envFilePath === undefined) {
    const message = `.env file not found`;
    console.error(`[prerun] ${message}`);
    throw new Error(message);
  }

  const parsedEnv = Dotenv.config({ path: envFilePath }).parsed || {};

  // compare env keys
  const existKeys = Object.keys(parsedEnv);
  const difference = requiredEnvKeys.filter((x) => !existKeys.includes(x));

  if (difference.length > 0) {
    throw new Error(
      `[prerun] Env validation failed. ${difference.join()} should exist.`,
    );
  }

  return parsedEnv;
}

function writeEnv(parsedEnv) {
  const scriptFilePath = `${fs.realpathSync(process.cwd())}/public/__ENV.js`;
  const content = `window.__ENV = ${JSON.stringify(parsedEnv)}`;
  fs.writeFileSync(scriptFilePath, content);
  console.info(
    `[prerun] Write environment to ${scriptFilePath} content: ${content}`,
  );
}

async function copyEnv(appEnv) {
  const envFilePath = await findUp(`.env`);
  const dotenvFilePath = `${fs.realpathSync(process.cwd())}/.env`;

  fs.copyFileSync(envFilePath, dotenvFilePath);
}

async function writeRobotsText(runType) {
  const robotsTxtFilePath = `${fs.realpathSync(
    process.cwd(),
  )}/public/robots.txt`;
  const content =
    runType === 'production'
      ? `User-agent: *\nAllow: /`
      : `User-agent: *\nDisallow: /`;
  fs.writeFileSync(robotsTxtFilePath, content);
  console.info(
    `[prerun] Write robots.txt to ${robotsTxtFilePath} content: ${content}`,
  );
}

yargs(hideBin(process.argv))
  .command(
    'start',
    'Create Next.js runtime environment js and write robots.txt',
    function builder(y) {
      return y.option('env', {
        alias: 'e',
        type: 'string',
        description: 'Environment name(ex: production, development)',
      });
    },
    async function handler(args) {
      const appEnv = '';
      console.info(`[env] App environment: ${appEnv}`);

      const parsedEnv = await parseDotenv();
      writeEnv(parsedEnv);
      await copyEnv(appEnv);
      writeRobotsText(parsedEnv.DOGU_RUN_TYPE);

      return parsedEnv;
    },
  )
  .parse();