ssh setup for private repo usages in expo eas

eas-build-pre-install.js

const { execSync } = require('child_process');
const fs = require('fs');
const path = require('path');

function present(value) {
  return value !== null && value !== undefined && value !== '';
}

console.log('Enabling corepack for yarn v4');
execSync('corepack enable && corepack prepare [email protected] --activate', {
  stdio: 'inherit',
});

const githubSshKey = process.env.GITHUB_SSH_KEY;

// For dev machines, they should already have the proper key, so local we'll
// not overwrite their keys if GITHUB_SSH_KEY is not set
if (present(githubSshKey)) {
  console.log('Setting up SSH Key for iOS Our internal dependencies');
  const sshDir = path.resolve(
    process.env.HOME || process.env.USERPROFILE,
    '.ssh',
  );

  if (!fs.existsSync(sshDir)) {
    fs.mkdirSync(sshDir, { recursive: true });
  }

  fs.writeFileSync(
    path.join(sshDir, 'id_rsa'),
    Buffer.from(githubSshKey, 'base64'),
  );
  fs.chmodSync(path.join(sshDir, 'id_rsa'), 0o600);

  execSync(
    `ssh-keygen -y -f ${path.join(sshDir, 'id_rsa')} > ${path.join(sshDir, 'id_rsa.pub')}`,
    { stdio: 'inherit' },
  );
  execSync(
    `ssh-keyscan -t rsa github.com >> ${path.join(sshDir, 'known_hosts')}`,
    { stdio: 'inherit' },
  );

  console.log('SSH Key setup done');
} else {
  console.log(
    'GITHUB_SSH_KEY not present, assuming build to be on dev machine (SSH setup skipped)',
  );
}

// other checks