Support filtering catalog entities (#3647)

* Support filtering catalog entities

- This allows extensions and OpenLens to restrict which of the entities
  the sources have provied are "visible" to the rest of Lens

Signed-off-by: Sebastian Malton <sebastian@malton.name>

* Fix lint

Signed-off-by: Sebastian Malton <sebastian@malton.name>

* switch to filtering only for catalog view

Signed-off-by: Sebastian Malton <sebastian@malton.name>

* Fix test

Signed-off-by: Panu Horsmalahti <phorsmalahti@mirantis.com>

* Add test to iter reduce

Signed-off-by: Panu Horsmalahti <phorsmalahti@mirantis.com>

Co-authored-by: Panu Horsmalahti <phorsmalahti@mirantis.com>

src/extensions/lens-renderer-extension.ts

@@ -21,9 +21,11 @@
 
 import type * as registries from "./registries";
 import type { Cluster } from "../main/cluster";
-import { LensExtension } from "./lens-extension";
+import { Disposers, LensExtension } from "./lens-extension";
 import { getExtensionPageUrl } from "./registries/page-registry";
 import type { CatalogEntity } from "../common/catalog";
+import type { Disposer } from "../common/utils";
+import { catalogEntityRegistry, EntityFilter } from "../renderer/api/catalog-entity-registry";
 
 export class LensRendererExtension extends LensExtension {
   globalPages: registries.PageRegistration[] = [];
@@ -59,4 +61,17 @@ export class LensRendererExtension extends LensExtension {
   async isEnabledForCluster(cluster: Cluster): Promise<Boolean> {
     return (void cluster) || true;
   }
+
+  /**
+   * Add a filtering function for the catalog. This will be removed if the extension is disabled.
+   * @param fn The function which should return a truthy value for those entities which should be kepted
+   * @returns A function to clean up the filter
+   */
+  addCatalogFilter(fn: EntityFilter): Disposer {
+    const dispose = catalogEntityRegistry.addCatalogFilter(fn);
+
+    this[Disposers].push(dispose);
+
+    return dispose;
+  }
 }