React Micro Frontend Utility Template

Getting Started

1. Run the script to initialize the project and install dependencies:

./setup.sh

2. Run yarn start --port ${YOUR_PORT} to run locally

3. Add your new micro frontend at the root config module inside root index.ejs or use Import Map Deployer

<script type="systemjs-importmap">
  {
    "imports": {
      "react": "https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js",
      "react-dom": "https://cdn.jsdelivr.net/npm/[email protected]/umd/react-dom.production.min.js",
      "single-spa": "https://cdn.jsdelivr.net/npm/[email protected]/lib/system/single-spa.min.js",
      "@${PROJECT_NAME}/root-config": "//localhost:9000/${PROJECT_NAME}-root-config.js",
      "@${PROJECT_NAME}/{UTILITY_MODULE_NAME}": "//localhost:${YOUR_PORT}/${PROJECT_NAME}-{UTILITY_MODULE_NAME}.js"
    }
  }
</script>

4. Register your utility module as external at webpack.config.js for each micro frontend

const { merge } = require('webpack-merge');
const singleSpaDefaults = require('webpack-config-single-spa-react-ts');

module.exports = (webpackConfigEnv, argv) => {
  const defaultConfig = singleSpaDefaults({
    orgName: '${PROJECT_NAME}',
    projectName: '${MICRO_FRONTEND_NAME}',
    webpackConfigEnv,
    argv,
  });

  return merge(defaultConfig, {
    // change the placeholders
    externals: ['${PROJECT_NAME}/{UTILITY_MODULE_NAME}'],
  });
};

5. Import your utilities at the micro frontend and use them

import { utilityName } from '@${PROJECT_NAME}/{UTILITY_MODULE_NAME}';

6. If you are using TypeScript at your micro frontend, it's recommended to use NPM when running ./setup.sh and then run yarn add @${PROJECT_NAME}/{UTILITY_MODULE_NAME}

This way, TypeScript will infer your types and code. Also, Jest won't fail when testing and not detecting a valid import of the utility

7. Run yarn start to run your root config module

8. Set devtools local storage key at browser console, whether your root module is running locally or it's using prod or dev environment.

localStorage.setItem('devtools', true);

• This will use import-map-overrides extension. This way, you can point the import map to your micro frontend that is running locally. Extension docs here here

Secrets

Setup secrets for S3 bucket names and roles to deploy to AWS at GitHub actions files. Secrets needed are:

• ACTIONS_DEPLOY_ACCESS_TOKEN: GitHub token used by Semantic Release
• FRONTEND_DEPLOYMENT_ROLE: IAM Role ARN
• BUCKET_NAME: S3 Bucket name
• MICRO_FRONTEND_NAME: Micro frontend name. This will be used to create a folder where you will have your micro frontend deployed JS files
• NPM_TOKEN: secret at your repository with an NPM Automation Access Token so that your utility can be deployed to NPM
• IMD_USERNAME: Username to authenticate in case you are using import map deployer
• IMD_PASSWORD: Password to authenticate in case you are using import map deployer
• IMD_HOST: Import map deployer domain name (without https)
• IMD_ENVIRONMENT: Import map deployer environment that you want to update (prod, dev, staging)
• CLOUDFRONT_HOST: Cloud front domain name (without https). This can also be Route 53, or S3 bucket domain in case you are not using CloudFront to host your import map JSON file.

This secrets should contain production values. Then, you can override secrets using Environment Secrets

Environments

• Create Development and Production environments and set each one to deploy from dev and master branches (Selected Branches rule)

• Each environment should have its own S3 Bucket, IAM Role for deployment and CloudFront distribution

• Setup environment secrets at Development so that the development FRONTEND_DEPLOYMENT_ROLE points to a role that will interact with the development S3 BUCKET_NAME

• Override IMD_ENVIRONMENT at Development Env Secret so that it points to dev, test or whatever name you gave to this env in your import map deployer server

• Change environment-url input passed down to deployment workflow so that each env will point to the corresponding CloudFront or Route 53 url

• Set run-import-map-deployer to true if you already stored the required import map secrets

Important notes

• Maintain consistency for the project name (all micro service and root project should have the same project name)

• It's recommended to use the root config module template from this template to be consistent with project naming convention

Import Map Deployer

• It's highly recommended to use Import Map Deployer so that this root repo will get the micro frontend imports from a dynamic import map JSON file. If you don't want to use it, remove the following lines at .github/workflows/build_and_deploy.yml

- name: Update import map
  run: curl -u ${USERNAME}:${PASSWORD} -d '{ "service":"@{YOUR_ORGANZATION_NAME}/'"${MICRO_FRONTEND_NAME}"'","url":"https://'"${CLOUDFRONT_HOST}"'/'"${MICRO_FRONTEND_NAME}"'/'"${IDENTIFIER}"'/'{YOUR_ORGANZATION_NAME}-"${MICRO_FRONTEND_NAME}"'.js" }' -X PATCH https://${IMD_HOST}/services/\?env=prod -H "Accept:application/json" -H "Content-Type:application/json"
  env:
    USERNAME: ${{ secrets.IMD_USERNAME }}
    PASSWORD: ${{ secrets.IMD_PASSWORD }}
    MICRO_FRONTEND_NAME: ${{ secrets.MICRO_FRONTEND_NAME }}
    CLOUDFRONT_HOST: ${{ secrets.CLOUDFRONT_HOST }}
    IMD_HOST: ${{ secrets.IMD_HOST }}
    IDENTIFIER: ${{ github.sha }}

• It will send a patch request to your import map deployer server located at ${IMD_HOST} domain name, at /services endpoint.

  • It sends a JSON body with the service that it want to update and the url key value pair containing the new utility module url.
  • It also sends the import map username and password in order to authenticate with the server

• If you are not using Import Map Deployer, add your compiled JS utility code at the root module import maps

  <% if (isLocal) { %>
  <script type="systemjs-importmap">
    {
      "imports": {
        "@${PROJECT_NAME}/root-config": "//localhost:9000/${PROJECT_NAME}-root-config.js",
        "@${PROJECT_NAME}/{UTILITY_MODULE_NAME}": "//localhost:${YOUR_PORT}/${PROJECT_NAME}-{UTILITY_MODULE_NAME}.js"
      }
    }
  </script>
  <% } else { %>
  <script type="systemjs-importmap">
    {
      "imports": {
        "@${PROJECT_NAME}/root-config": "https://{S3_BUCKET_NAME}.s3.amazonaws.com/${PROJECT_NAME}-root-config.js",
        "@${PROJECT_NAME}/{UTILITY_MODULE_NAME}": "https://{S3_BUCKET_NAME}.s3.amazonaws.com/${PROJECT_NAME}-{UTILITY_MODULE_NAME}.js"
      }
    }
  </script>
  <% } %>

Semantic Release

• Set ACTIONS_DEPLOY_ACCESS_TOKEN secret at your repository with a GitHub Personal Access Token so that Semantic Release can work properly

  • This token should have full control of private repositories

Deploying Package to NPM

• Set NPM_TOKEN secret at your repository with an NPM Automation Access Token so that your utility can be deployed to NPM

It's highly recommended to publish your package to NPM so that you don't have TypeScript errors about not finding your utility module when it is imported at your micro frontends.

• Your ${PROJECT_NAME} prompted when running ´./setup.sh´ should be the same as your organization or username from NPM. This way, you will avoid errors when executing your GitHub actions pipeline at ´npm publish --access=public´ step

You can remove ´--access=public´ option from ´npm publish´ if you can publish private packages to NPM

• You can remove the ´.github´ folder if you don't want to use CI / CD GitHub actions for semantic release, publish to NPM, automated testing and deployment.

Deployment in AWS

• Build the project with yarn build and deploy the files to a CDN (CloudFront + S3) or host to serve those static files.

• According with .github/workflows/main.yml, the action will assume a role through GitHub OIDC and AWS STS. This role has permissions to put new objects in your S3 bucket

  • This action step will send the build files generated at dist folder to s3://${BUCKET_NAME}/${MICRO_FRONTEND_NAME}/${IDENTIFIER}
  • That way, it will store your utility compiled code at the same folder ${MICRO_FRONTEND_NAME} and store each new version with GitHub Commit SHA ${IDENTIFIER}

• Import map deployer step then will update import-map.json file in your S3 bucket with the new compiled file route

• All the instructions to deploy the whole infrastructure to AWS are at Micro Frontend Root Documentation