RHDH Backend Dynamic Plugin Bootstrap

Purpose

Bootstrap a new backend dynamic plugin for Red Hat Developer Hub (RHDH). RHDH is the enterprise-ready Backstage applicationthat supports dynamic plugins - plugins that can be installed or uninstalled without rebuilding the application.

Note: This skill covers backend plugins only. Frontend dynamic plugins have different requirements (Scalprum configuration, mount points, dynamic routes) and are covered in a separate skill.

When to Use

Use this skill when creating a new backend plugin intended for RHDH dynamic plugin deployment. This includes:

• New backend API plugins
• Backend modules for existing plugins (e.g., catalog-backend-module-*)
• Scaffolder actions and templates
• Catalog processors and providers
• Authentication modules
• Any server-side functionality for RHDH

Do NOT use this skill for:

• Frontend plugins (UI components, pages, cards)
• Frontend plugin wiring (mount points, dynamic routes)
• Themes or frontend customizations

Prerequisites

Before starting, ensure the following are available:

• Node.js 22+ and Yarn
• Container runtime (podman or docker)
• Access to a container registry (e.g., quay.io) for publishing

Workflow Overview

1. Determine RHDH Version - Identify target RHDH version for compatibility
2. Create Backstage App - Scaffold Backstage app with matching version
3. Create Backend Plugin - Generate new backend plugin using Backstage CLI
4. Implement Plugin Logic - Write the plugin code using new backend system
5. Export and Package - Build, export, and package using RHDH CLI (see export-and-package skill)
6. Configure for RHDH - Create dynamic-plugins.yaml configuration

Step 1: Determine RHDH Version

Check the target RHDH version and find the compatible Backstage version. Consult ../rhdh/references/versions.md file for the version compatibility matrix and available RHDH versions.

Ask the user which RHDH version they are targeting if not specified.

Step 2: Create Backstage Application

Create a new Backstage application in the current directory using the version-appropriate create-app:

# For RHDH 1.8 (adjust version as needed)
echo "backstage" | npx @backstage/create-app@0.7.3 --path .

After creation, install dependencies:

yarn install

The only purpose this serves is to ensure you can later create the plugin using the correct version of the Backstage CLI. All development and testing will be done in the plugin directory.

Step 3: Create Backend Plugin

Generate a new backend plugin using the Backstage CLI:

yarn new

When prompted:

1. Select "backend-plugin" as the plugin type
2. Enter a plugin ID (e.g., my-plugin)
3. The plugin will be created at plugins/<plugin-id>-backend/

The generated plugin structure:

plugins/<plugin-id>-backend/
├── src/
│   ├── index.ts           # Main entry point
│   ├── plugin.ts          # Plugin definition (new backend system)
│   └── service/
│       └── router.ts      # Express router
├── package.json
└── README.md

Step 4: Implement Plugin Logic

Backend plugins must use the new backend system for dynamic plugin compatibility. The plugin entry point should export a default using createBackendPlugin() or createBackendModule().

Example plugin structure (src/plugin.ts):

import {
  coreServices,
  createBackendPlugin,
} from '@backstage/backend-plugin-api';
import { createRouter } from './service/router';

export const myPlugin = createBackendPlugin({
  pluginId: 'my-plugin',
  register(env) {
    env.registerInit({
      deps: {
        httpRouter: coreServices.httpRouter,
        logger: coreServices.logger,
        config: coreServices.rootConfig,
      },
      async init({ httpRouter, logger, config }) {
        httpRouter.use(
          await createRouter({
            logger,
            config,
          }),
        );
        httpRouter.addAuthPolicy({
          path: '/health',
          allow: 'unauthenticated',
        });
      },
    });
  },
});

export default myPlugin;

The src/index.ts must export the plugin as default:

export { default } from './plugin';

Build and verify the plugin compiles:

cd plugins/<plugin-id>-backend
yarn build

Step 5: Export and Package

Export the plugin as a dynamic plugin and package it for deployment. For detailed export and packaging options, see the export-and-package skill.

Quick Export

cd plugins/<plugin-id>-backend
npx @red-hat-developer-hub/cli@latest plugin export

This creates dist-dynamic/ with the dynamic plugin package.

Quick Package and Push

npx @red-hat-developer-hub/cli@latest plugin package \
  --tag quay.io/<namespace>/<plugin-name>:v0.1.0

podman push quay.io/<namespace>/<plugin-name>:v0.1.0

For advanced options (dependency handling, multi-plugin bundles, tgz/npm packaging), consult the export-and-package skill.

Step 6: Configure for RHDH

Create the dynamic plugin configuration for RHDH. Add to dynamic-plugins.yaml:

plugins:
  - package: oci://quay.io/<namespace>/<plugin-name>:v0.1.0!<plugin-id>-backend-dynamic
    disabled: false
    pluginConfig:
      # Plugin-specific configuration (optional)
      myPlugin:
        someOption: value

For local development/testing, copy dist-dynamic to RHDH's dynamic-plugins-root:

cp -r dist-dynamic /path/to/rhdh/dynamic-plugins-root/<plugin-id>-backend-dynamic

See examples/dynamic-plugins.yaml for a complete configuration example.

Common Issues

Plugin Not Loading

• Verify plugin uses new backend system (createBackendPlugin)
• Check plugin is exported as default export
• Ensure version compatibility with target RHDH

Dependency Conflicts

• Use --shared-package to exclude problematic shared deps
• Use --embed-package to bundle required deps

Build Failures

• Run yarn tsc to check TypeScript errors before export
• Ensure all @backstage/* versions match target RHDH

Additional Resources

Related Skills

• export-and-package - Complete export/packaging workflow (OCI, tgz, npm)

Reference Files

• rhdh/references/versions.md - Complete version compatibility matrix

Example Files

• examples/dynamic-plugins.yaml - Example RHDH plugin configuration

External Resources

• RHDH Dynamic Plugins Documentation
• Backstage New Backend System