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 as Dynamic Plugin - Build and export using RHDH CLI
6. Package as OCI Image - Create container image for deployment
7. 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 references/versions.md for the version compatibility matrix.

RHDH Version	Backstage Version	create-app Version
1.8 / next	1.42.5	0.7.3
1.7	1.39.1	0.6.2
1.6	1.36.1	0.5.25
1.5	1.35.1	0.5.24

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

Step 2: Create Backstage Application

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

# For RHDH 1.7 (adjust version as needed)
npx @backstage/create-app@0.6.2

# Follow prompts to name the application
# This creates the monorepo structure needed for plugin development

After creation, navigate to the app directory and install dependencies:

cd <app-name>
yarn install

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 as Dynamic Plugin

Use the RHDH CLI to export the plugin as a dynamic plugin package:

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

This command:

• Builds the plugin
• Creates dist-dynamic/ directory with the dynamic plugin package
• Configures dependencies (peer vs bundled)
• Generates config schema

The CLI automatically handles:

• Shared dependencies: @backstage/* packages become peerDependencies
• Bundled dependencies: Non-backstage deps are bundled in the package
• Embedded packages: -node and -common suffix packages are embedded

For custom dependency handling, use flags:

# Mark a @backstage package as NOT shared (bundle it)
npx @red-hat-developer-hub/cli@latest plugin export \
  --shared-package '!/@backstage/plugin-notifications/'

# Embed a specific package
npx @red-hat-developer-hub/cli@latest plugin export \
  --embed-package @my-org/common-utils

See references/export-guide.md for detailed export options.

Step 6: Package as OCI Image

Package the dynamic plugin as an OCI container image for distribution:

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

Push the image to your container registry:

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

See references/packaging-guide.md for alternative packaging methods (tgz, npm).

Step 7: 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.

Debugging

For local debugging of dynamic plugins:

1. Build and copy plugin to dynamic-plugins-root/
2. Start RHDH backend with debugging:

   yarn workspace backend start --inspect
   

3. Attach IDE debugger to port 9229
4. Set breakpoints in dynamic-plugins-root/<plugin-id>/ files

See references/debugging.md for container-based debugging.

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

Reference Files

For detailed documentation, consult:

• references/versions.md - Complete version compatibility matrix
• references/export-guide.md - Detailed export options and flags
• references/packaging-guide.md - OCI, tgz, and npm packaging
• references/debugging.md - Local and container debugging

Example Files

Examples in examples/:

• dynamic-plugins.yaml - Example RHDH plugin configuration

External Resources

• RHDH Dynamic Plugins Documentation
• Backstage New Backend System