Deploy hooks for Firebase Functions + Yarn Workspaces

deploy-hooks.js

#!/usr/bin/env node

/**
 * @description Firebase Functions Workspace Deploy Hooks
 * @author Niels Maerten <https://github.com/nielsmaerten>
 * @license MIT
 * 
 * This script is designed for Yarn v3 workspaces.
 * 
 * ### WHAT DOES THIS SCRIPT DO? ###
 * Firebase Functions do not support 'monorepos'. This means that you can not
 * have dependencies in package.json that point to 'workspace:my-package-name'.
 * This script will find your workspace dependencies, package them, and copy the tgz-file
 * into this project before deploying.
 * 
 * When the deploy is complete and this script runs again, the original package.json is restored.
 * 
 * By doing this, it is possible to slipstream workspace dependencies into your project
 * and have it run on Cloud Functions
 */

const logTag = "[GLOBAL]";
const fs = require('fs');

// Find all dependencies in package.json where the value starts with 'workspace:'
const workspaceDeps = Object.entries(require('./package.json').dependencies).filter(([key, value]) => value.startsWith('workspace:'));

// This is a preDeploy if workspaceDeps has any entries
const isPreDeploy = workspaceDeps.length > 0;
const prePostDeploy = isPreDeploy ? 'Pre-deploy' : 'Post-deploy';

// If this is a preDeploy: backup the local package.json
// else: restore the backup
if (isPreDeploy) {
  console.log(logTag, 'Backing up package.json');
  fs.copyFileSync('./package.json', './package.json.bak');
} else {
  console.log(logTag, 'Restoring package.json backup');
  fs.copyFileSync('./package.json.bak', './package.json');
  fs.unlinkSync('./package.json.bak');
}

// If preDeploy: Package all workspace dependencies into this directory
workspaceDeps.forEach(([workspace]) => {
  const logTag = `[${workspace}]`;
  console.log(logTag, `Running yarn pack`);

  const workspacePath = `../${workspace}`;
  const packageFilename = `${workspace}.tgz`;
  const packCommand = `yarn pack --filename ${packageFilename}`;
  const packResult = require('child_process').execSync(packCommand, { cwd: workspacePath });
  // console.log(packResult.toString());

  // Copy the package into this directory using node fs
  console.log(logTag,`Copying package into this directory`);
  const packPath = `${workspacePath}/${packageFilename}`;
  const targetPath = `${__dirname}/${packageFilename}`;
  fs.copyFileSync(packPath, targetPath);

  // Update the package in the local package.json
  console.log(logTag, `Updating local package.json`);
  const localPackageJson = require('./package.json');
  localPackageJson.dependencies[workspace] = `file:${packageFilename}`;
  fs.writeFileSync('./package.json', JSON.stringify(localPackageJson, null, 2));
  console.log(logTag, `Workspace successfully packaged into this directory`);
});

// If postDeploy, remove .tgz files in current dir
if (!isPreDeploy) {
  console.log(logTag, 'Removing .tgz files');
  fs.readdirSync(__dirname).forEach(file => {
    if (file.endsWith('.tgz')) {
      fs.unlinkSync(`${__dirname}/${file}`);
    }
  });
}

console.log(logTag, prePostDeploy, "hook ran successfully");