feat(npm): add backend to fetch data from private registries

workspaces/npm/.changeset/polite-houses-flow.md

@@ -0,0 +1,7 @@
+---
+'@backstage-community/plugin-npm-backend': minor
+'@backstage-community/plugin-npm-common': minor
+'@backstage-community/plugin-npm': minor
+---
+
+Added support for custom and private npm registries like GitHub and GitLab via a new backend plugin. Other npm registries that works with the npm cli should work as well.

workspaces/npm/README.md

@@ -1,16 +1,324 @@
-# [Backstage](https://backstage.io)
+# npm plugin for Backstage
 
-This is your newly scaffolded Backstage App, Good Luck!
+A Backstage plugin that shows information and latest releases/versions
+from a npm registry for catalog entities.
 
-To start the app, run:
+The current version can show two cards and one additional tab for an catalog entity.
 
-```sh
-yarn install
-yarn dev
+1. The "Npm info card" shows general information like the latest version, description, etc.
+2. The "Npm release overview card" shows the latest tags of an npm package.
+3. The "Npm release tab" shows the version hisory in detail.
+
+## Screenshots
+
+### Npm info card
+
+![Screenshot](docs/npm-info-card.png)
+
+### Npm release overview card
+
+![Screenshot](docs/npm-release-overview-card.png)
+
+### Extended catalog entity overview tab (example)
+
+![Screenshot](docs/catalog-entity-overview-tab.png)
+
+### New catalog entity npm release tab
+
+![Screenshot](docs/catalog-entity-npm-release-tab.png)
+
+## Usage
+
+### Enable npm cards for a catalog entity
+
+To enable the different npm cards you must add the `npm/package` annotation
+with the name of the npm package:
+
+```yaml
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: react
+  annotations:
+    npm/package: react
+```
+
+### Use other npm tag then `latest`
+
+The "npm info" card shows the information of the latest 'stable' npm release
+and use the common `latest` tag by default. This could be changed with `npm/stable-tag`:
+
+```yaml
+# catalog-info.yaml
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: react
+  annotations:
+    npm/package: react
+    npm/stable-tag: latest, stable, next, etc.
 ```
 
-To generate knip reports for this app, run:
+### Use a custom registry
+
+To use another npm registry you need to specific a registry name in your
+catalog entity that exists in your `app-config.yaml`.
 
-```sh
-yarn backstage-repo-tools knip-reports
+```yaml
+# catalog-info.yaml
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: react
+  annotations:
+    npm/package: another-package
+    npm/registry: github
 ```
+
+```yaml
+# app-config.yaml
+npm:
+  registries:
+    - name: github
+      url: https://npm.pkg.github.com
+      token: ghp_...
+```
+
+## Installation
+
+To show information from a private package or an alternative npm registry
+you must install also the backend plugin and [configure it](./registries.md).
+
+### Frontend plugin
+
+1. Install the frontend dependency:
+
+   ```sh
+   yarn workspace app add @backstage-community/plugin-npm
+   ```
+
+2. Add cards based on your needs to `packages/app/src/components/catalog/EntityPage.tsx`:
+
+   After all other imports:
+
+   ```tsx
+   import {
+     isNpmAvailable,
+     EntityNpmInfoCard,
+     EntityNpmReleaseOverviewCard,
+     EntityNpmReleaseTableCard,
+   } from '@backstage-community/plugin-npm';
+   ```
+
+3. Add to `const overviewContent` after `EntityAboutCard`:
+
+   ```tsx
+   <EntitySwitch>
+     <EntitySwitch.Case if={isNpmAvailable}>
+       <Grid container item md={6} xs={12}>
+         <Grid item md={12}>
+           <EntityNpmInfoCard />
+         </Grid>
+         <Grid item md={12}>
+           <EntityNpmReleaseOverviewCard />
+         </Grid>
+       </Grid>
+     </EntitySwitch.Case>
+   </EntitySwitch>
+   ```
+
+4. Add to `const serviceEntityPage` and `const websiteEntityPage` after the `/ci-cd` case
+   and to `const defaultEntityPage` between the `/` and `/docs` routecase.
+
+   ```tsx
+   <EntityLayout.Route
+     if={isNpmAvailable}
+     path="/npm-releases"
+     title="NPM Releases"
+   >
+     <EntityNpmReleaseTableCard />
+   </EntityLayout.Route>
+   ```
+
+### Alternative: Use the new frontend system (alpha)
+
+For early adaopters of the new frontend system.
+
+Your Backstage frontend app must use that new frontend system which isn't the default at the moment.
+
+1. Install the frontend dependency:
+
+   ```sh
+   yarn workspace app-next add @backstage-community/plugin-npm
+   ```
+
+2. Add the package to your `packages/app[-next]/src/App.tsx`.
+
+   ```tsx
+   import npmPlugin from '@backstage-community/plugin-npm/alpha';
+   ```
+
+   And extend your createApp:
+
+   ```tsx
+   export const app = createApp({
+     features: [
+       catalogPlugin,
+       catalogImportPlugin,
+       userSettingsPlugin,
+       npmPlugin,
+       // ...
+     ],
+   });
+   ```
+
+### Optional: Backend plugin (req. for private packages or alternative registries)
+
+1. Install the backend plugin:
+
+   ```sh
+   yarn workspace backend add @backstage-community/plugin-npm
+   ```
+
+2. Add it to `packages/backend/src/index.ts`:
+
+   ```tsx
+   backend.add(import('@backstage-community/plugin-npm-backend'));
+   ```
+
+3. The backend is only used for catalog entities with a registry by default.
+
+   If no `npm/registry` annotation is defined, the npm plugin loads the
+   information directly from the frontend.
+   (The browser of the user will connect to https://registry.npmjs.com.)
+
+   You can enforce using the backend by defining a default registry:
+
+   ```yaml
+   # app-config.yaml
+   # optional to enforce the frontend to use the backend
+   npm:
+     defaultRegistry: npmjs
+   ```
+
+For more information, please checkout the [Registries](./registries.md) documentation.
+
+### Optional: Test with plugin-example catalog entities
+
+For testing purpose you can import this catalog entities:
+
+```yaml
+# catalog-info.yaml
+catalog:
+  locations:
+    - type: url
+      target: https://github.com/backstage/community-plugins/blob/main/workspaces/npm/examples/entities.yaml
+      rules:
+        - allow: [System, Component]
+```
+
+## Registries
+
+The npm plugin supports custom and private registries starting with v1.2.
+
+### Default Configuration
+
+The plugin loads information by default from https://registry.npmjs.com
+
+This works without any additional configuration in your `app-config.yaml`
+but only for public npm packages.
+
+```yaml
+npm:
+  registries:
+    - name: npmjs
+      url: https://registry.npmjs.com
+```
+
+### Use an auth token for npmjs
+
+To load information from another registry or to load information
+from a private package, you must [install the backend](./install.md).
+
+The catalog entity `npm/registry` annotation must be defined and match
+one of the registries in the `app-config.yaml`:
+
+Example:
+
+```yaml
+# catalog-info.yaml
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: a-component
+  annotations:
+    npm/package: private-package
+    npm/registry: npmjs
+```
+
+```yaml
+# app-config.yaml
+npm:
+  registries:
+    - name: npmjs
+      url: https://registry.npmjs.com
+      token: ...
+```
+
+The `npm/registry: npmjs` annotation is required to use the npm backend.
+
+Alternativly you can setup a default registry (also for npmjs):
+
+```yaml
+# app-config.yaml
+npm:
+  defaultRegistry: npmjs
+```
+
+### Use an alternative registry
+
+Entity example:
+
+```yaml
+# catalog-info.yaml
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: a-component
+  annotations:
+    npm/package: private-package
+    npm/registry: private-registry
+```
+
+```yaml
+# app-config.yaml
+npm:
+  registries:
+    - name: private-registry
+      url: https://...
+      token: ...
+```
+
+### Use GitHub npm registry
+
+The GitHub npm registry reqires also a GitHub token for public entries.
+
+You need to create a token at https://github.com/settings/tokens
+
+```yaml
+# app-config.yaml
+npm:
+  registries:
+    - name: github
+      url: https://npm.pkg.github.com
+      token: ghp_...
+```
+
+### Other npm registries
+
+Other npm registries should work the same way.
+
+Please let us know if we should mention here another registry or
+if you find any issue.
+
+You can create a new [Issues on GitHub](https://github.com/backstage/community-plugins/issues/new?assignees=&labels=bug&projects=&template=1-bug.yaml&title=🐛+Npm%3A+<Title>)