@dweber019/backstage-plugin-relations-backend NPM

Relations processor

This relations processor plugin emits additional custom relations, which are shown in the Catalog Graph out of box.

Additionally, you can install the Relations frontend plugin for a better frontend experience with this processor.

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Install

Setup plugin

First we need to add the @dweber019/backstage-plugin-relations-backend package:

# From your Backstage root directory
yarn --cwd packages/backend add @dweber019/backstage-plugin-relations-backend

Then we open the file named packages/backend/src/plugins/catalog.ts, and extend it with:

import { RelationsEntitiesProcessor } from '@dweber019/backstage-plugin-relations-backend';

export default async function createPlugin(
  env: PluginEnvironment,
): Promise<Router> {
  const builder = await CatalogBuilder.create(env);

  builder.addProcessor(RelationEntitiesProcessor.fromConfig(env));

  const { processingEngine, router } = await builder.build();
  // ..
}

Configuration

See the config.d.ts file for a documentation of the configuration.

Here is a simple configuration, which will add an attribute named supporter, which allows relations to User and Group on a Resource. Additionally, we can use the attribute applicationOwner on Component to allow relations to a User.

relationsProcessor:
  relations:
    - sourceKind: component
      targetKinds:
        - user
      attribute: applicationOwner
      pairs:
        - incoming: applicationOwnerOf
          outgoing: applicationOwnerBy
    - sourceKind: resource
      targetKinds:
        - user
        - group
      attribute: supporter
      multi: true
      pairs:
        - incoming: supporterOf
          outgoing: supportedBy

Usage

The above definitions would allow to define the following entities

apiVersion: backstage.io/v1alpha1
kind: Resource
metadata:
  name: resource-1
spec:
  type: db
  owner: group:default/group-1
  supporter:
    - john-doe
    - group:default/group-1
---
apiVersion: backstage.io/v1alpha1
kind: Component
metadata:
  name: component-1
spec:
  type: service
  lifecycle: production
  owner: group:default/group-1
  applicationOwner: user:default/kevin-po

Catalog graph

It's recommend to use the Relations frontend plugin to add new relations to the filters and set good defaults.

Using well known relations

You can use the Well-known Relations between Catalog Entities relations with this plugin. This is useful if a component is owned by a group and has an application owner, which should have an ownership too.

apiVersion: backstage.io/v1alpha1
kind: Component
metadata:
  name: component-1
spec:
  type: service
  lifecycle: production
  owner: group:default/group-1
  applicationOwner: user:default/kevin-po

To enable the owner relation use the following configuration.

relationsProcessor:
  relations:
    - sourceKind: component
      targetKinds:
        - user
      attribute: applicationOwner
      pairs:
        - incoming: applicationOwnerOf
          outgoing: applicationOwnerBy
        - incoming: ownerOf
          outgoing: ownerBy

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New Backend System

The backend plugin has support for the new backend system, here's how you can set that up:

In your packages/backend/src/index.ts make the following changes:

const backend = createBackend();

backend.add(import('@dweber019/backstage-plugin-relations-backend'));

// ... other feature additions

backend.start();