add annotation check

this helps with configurability of the plugins
so that the plugins only show for the components
with the right set of annotations on them

README.md

@@ -46,7 +46,7 @@ const serviceEntityPage = (
 
     ...
 
-    <EntityLayout.Route path="/apache-spark" title="Spark">
+    <EntityLayout.Route path="/apache-spark" title="Spark" if={isApacheSparkAvailable}>
       <ApacheSparkPage />
     </EntityLayout.Route>
 
@@ -57,16 +57,11 @@ const serviceEntityPage = (
 ```
 
 #### Annotations
+- `apache-spark.cnoe.io/label-selector`: Required. This value corresponds to the label on
+  the Pod running the Spark job.
 - `backstage.io/kubernetes-namespace`: Optional. Defaults to the `default` namespace.
-- `apache-spark.cnoe.io/label-selector`: This value takes precedent over the one above.
 - `apache-spark.cnoe.io/cluster-name`: Optional. Specifies the name of Kubernetes cluster to retrieve information from.
 
-you can also use the `backstage.io/kubernetes-label-selector`, to select the
-relevant spark jobs. However , `backstage.io/kubernetes-label-selector` is a
-generic label selector used more widely by the Kubernetes plugin which could
-pull other less relevant data pulled into your backstage deployment as well. We
-recommend using `apache-spark.cnoe.io/label-selector` when using this plugin.
-
 ### Authentication
 
 This plugin uses the Kubernetes plugin for authentication. 

src/components/utils.ts

@@ -1,8 +1,7 @@
-import { Entity } from '@backstage/catalog-model';
+import {Entity} from '@backstage/catalog-model';
 import {
   APACHE_SPARK_LABEL_SELECTOR_ANNOTATION,
   CLUSTER_NAME_ANNOTATION,
-  K8S_LABEL_SELECTOR_ANNOTATION,
   K8S_NAMESPACE_ANNOTATION,
 } from '../consts';
 
@@ -18,11 +17,7 @@ export function getAnnotationValues(entity: Entity): getAnnotationValuesOutput {
       ? entity.metadata.annotations?.[K8S_NAMESPACE_ANNOTATION]
       : 'default';
   const clusterName = entity.metadata.annotations?.[CLUSTER_NAME_ANNOTATION];
-  const labelSelector =
-    entity.metadata?.annotations?.[APACHE_SPARK_LABEL_SELECTOR_ANNOTATION] !==
-    undefined
-      ? entity.metadata?.annotations?.[APACHE_SPARK_LABEL_SELECTOR_ANNOTATION]
-      : entity.metadata.annotations?.[K8S_LABEL_SELECTOR_ANNOTATION];
+  const labelSelector = entity.metadata?.annotations?.[APACHE_SPARK_LABEL_SELECTOR_ANNOTATION]
   return {
     ns: ns,
     clusterName: clusterName,

src/index.ts

@@ -1 +1 @@
-export { apacheSparkPlugin, ApacheSparkPage } from './plugin';
+export {apacheSparkPlugin, ApacheSparkPage, isApacheSparkAvailable} from './plugin';

src/plugin.ts

@@ -4,9 +4,17 @@ import {
   createRoutableExtension,
 } from '@backstage/core-plugin-api';
 
-import { rootRouteRef } from './routes';
-import { apacheSparkApiRef, ApacheSparkClient } from './api';
-import { kubernetesApiRef } from '@backstage/plugin-kubernetes';
+import {rootRouteRef} from './routes';
+import {apacheSparkApiRef, ApacheSparkClient} from './api';
+import {kubernetesApiRef} from '@backstage/plugin-kubernetes';
+import {Entity} from '@backstage/catalog-model';
+
+import {
+  APACHE_SPARK_LABEL_SELECTOR_ANNOTATION,
+} from './consts';
+
+export const isApacheSparkAvailable = (entity: Entity) =>
+  Boolean(entity.metadata.annotations?.[APACHE_SPARK_LABEL_SELECTOR_ANNOTATION]);
 
 export const apacheSparkPlugin = createPlugin({
   id: 'apache-spark',
@@ -19,7 +27,7 @@ export const apacheSparkPlugin = createPlugin({
       deps: {
         kubernetesApi: kubernetesApiRef,
       },
-      factory: ({ kubernetesApi }) => new ApacheSparkClient(kubernetesApi),
+      factory: ({kubernetesApi}) => new ApacheSparkClient(kubernetesApi),
     }),
   ],
 });