add some documentation

plugins/apache-spark/README.md

@@ -1,13 +1,76 @@
-# apache-spark
+# Apache Spark Plugin for Backstage
 
-Welcome to the apache-spark plugin!
+Welcome to the Apache Spark plugin for Backstage!
 
-_This plugin was created through the Backstage CLI_
+This plugin allows you to display information related to your Apache Spark Applications running in Kubernetes on Backstage
 
 ## Getting started
 
-Your plugin has been added to the example app in this repository, meaning you'll be able to access it by running `yarn start` in the root directory, and then navigating to [/apache-spark](http://localhost:3000/apache-spark).
+![GIF](doc/images/demo1.gif)
 
-You can also serve the plugin in isolation by running `yarn start` in the plugin directory.
-This method of serving the plugin provides quicker iteration speed and a faster startup and hot reloads.
-It is only meant for local development, and the setup for it can be found inside the [/dev](./dev) directory.
+
+### Configuration
+
+Entities must be annotated with Kubernetes annotations. For example:
+
+[The Kubernetes plugin](https://backstage.io/docs/features/kubernetes/) must also be installed and enabled.  
+
+```yaml
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: backstage
+  annotations:
+    backstage.io/kubernetes-namespace: default
+    backstage.io/kubernetes-label-selector: env=dev,my=label
+```
+
+Update your Entity page. For example:
+```typescript
+// in packages/app/src/components/catalog/EntityPage.tsx
+
+```
+
+
+#### Annotations
+- `backstage.io/kubernetes-namespace`: Optional. Defaults to the `default` namespace.
+- `backstage.io/kubernetes-label-selector`: Conditionally required. One of label selectors must be defined.
+- `apache-spark/label-selector`: Conditionally required. One of label selectors must be defined. This value takes precedent over the one above.
+- `apache-spark/cluster-name`: Optional. Specifies the name of Kubernetes cluster to retrieve information from.
+
+### Authentication
+
+This plugin uses the Kubernetes plugin for authentication. 
+
+#### Using configured Kubernetes API
+
+The plugin uses configured Kubernetes clusters to fetch resources.
+
+For example, for a Kubernetes cluster given in your `app-config.yaml`
+
+```yaml
+kubernetes:
+  serviceLocatorMethod:
+    type: "multiTenant"
+  clusterLocatorMethods:
+    - type: "config"
+      clusters:
+        - url: https://abcd.gr7.us-west-2.eks.amazonaws.com:443
+          name: my-cluster-1
+          authProvider: "serviceAccount"
+          serviceAccountToken: eyJh
+          caData: LS0t
+```
+
+For this configuration, the `argo-workflows/cluster-name` annotation value must be `my-cluster-1`. If this is not specified, the first cluster in the list is selected.
+
+```yaml
+apiVersion: backstage.io/v1alpha1
+kind: Component
+metadata:
+  name: backstage
+  annotations:
+    backstage.io/kubernetes-namespace: default
+    backstage.io/kubernetes-label-selector: env=dev,my=label
+    argo-workflows/cluster-name: my-cluster-1
+```

plugins/apache-spark/src/plugin.ts

@@ -2,8 +2,6 @@ import {
   createApiFactory,
   createPlugin,
   createRoutableExtension,
-  discoveryApiRef,
-  fetchApiRef,
 } from '@backstage/core-plugin-api';
 
 import { rootRouteRef } from './routes';