Discovery Service

When building plugins, you might find that you will need to look up another plugin's base URL to be able to communicate with it. This could be for example an HTTP route or some ws protocol URL. For this we have a discovery service which can provide both internal and external base URLs for a given a plugin ID.

Using the service

The following example shows how to get the discovery service in your example backend plugin and making a request to both the internal and external base URLs for the derp plugin.

import {
  coreServices,
  createBackendPlugin,
} from '@backstage/backend-plugin-api';
import { fetch } from 'node-fetch';

createBackendPlugin({
  pluginId: 'example',
  register(env) {
    env.registerInit({
      deps: {
        discovery: coreServices.discovery,
      },
      async init({ discovery }) {
        const url = await discovery.getBaseUrl('derp'); // can also use discovery.getExternalBaseUrl to retrieve external URL
        const response = await fetch(`${url}/hello`);
      },
    });
  },
});