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>

src/common/utils/iter.ts

@@ -156,3 +156,19 @@ export function find<T>(src: Iterable<T>, match: (i: T) => any): T | undefined {
 
   return void 0;
 }
+
+/**
+ * Iterate over `src` calling `reducer` with the previous produced value and the current
+ * yielded value until `src` is exausted. Then return the final value.
+ * @param reducer A function for producing the next item from an accumilation and the current item
+ * @param initial The initial value for the iteration
+ */
+export function reduce<T, R = T>(src: Iterable<T>, reducer: (acc: R, cur: T) => R, initial: R): R {
+  let acc = initial;
+
+  for (const item of src) {
+    acc = reducer(acc, item);
+  }
+
+  return acc;
+}

src/extensions/lens-main-extension.ts

@@ -19,12 +19,13 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-import { LensExtension } from "./lens-extension";
+import { Disposers, LensExtension } from "./lens-extension";
 import { WindowManager } from "../main/window-manager";
-import { catalogEntityRegistry } from "../main/catalog";
+import { catalogEntityRegistry, EntityFilter } from "../main/catalog";
 import type { CatalogEntity } from "../common/catalog";
 import type { IObservableArray } from "mobx";
 import type { MenuRegistration } from "./registries";
+import type { Disposer } from "../common/utils";
 
 export class LensMainExtension extends LensExtension {
   appMenus: MenuRegistration[] = [];
@@ -33,6 +34,19 @@ export class LensMainExtension extends LensExtension {
     return WindowManager.getInstance().navigateExtension(this.id, pageId, params, frameId);
   }
 
+  /**
+   * 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;
+  }
+
   addCatalogSource(id: string, source: IObservableArray<CatalogEntity>) {
     catalogEntityRegistry.addObservableSource(`${this.name}:${id}`, source);
   }

src/main/catalog/__tests__/catalog-entity-registry.test.ts

@@ -20,7 +20,7 @@
  */
 
 import { observable, reaction } from "mobx";
-import { WebLink, WebLinkSpec, WebLinkStatus } from "../../../common/catalog-entities";
+import { KubernetesCluster, WebLink, WebLinkSpec, WebLinkStatus } from "../../../common/catalog-entities";
 import { catalogCategoryRegistry, CatalogEntity, CatalogEntityMetadata } from "../../../common/catalog";
 import { CatalogEntityRegistry } from "../catalog-entity-registry";
 
@@ -61,6 +61,35 @@ describe("CatalogEntityRegistry", () => {
       phase: "available"
     }
   });
+  const entity2 = new WebLink({
+    metadata: {
+      uid: "test2",
+      name: "test-link",
+      source: "test",
+      labels: {}
+    },
+    spec: {
+      url: "https://k8slens.dev"
+    },
+    status: {
+      phase: "available"
+    }
+  });
+  const entitykc = new KubernetesCluster({
+    metadata: {
+      uid: "test2",
+      name: "test-link",
+      source: "test",
+      labels: {}
+    },
+    spec: {
+      kubeconfigPath: "",
+      kubeconfigContext: "",
+    },
+    status: {
+      phase: "connected"
+    }
+  });
   const invalidEntity = new InvalidEntity({
     metadata: {
       uid: "invalid",
@@ -132,5 +161,17 @@ describe("CatalogEntityRegistry", () => {
       registry.addObservableSource("test", source);
       expect(registry.items.length).toBe(0);
     });
+
+    it("does not return items that are filtered out", () => {
+      const source = observable.array([entity, entity2, entitykc]);
+
+      registry.addObservableSource("test", source);
+      expect(registry.items.length).toBe(3);
+
+      const d = registry.addCatalogFilter(entity => entity.kind === KubernetesCluster.kind);
+      expect(registry.items.length).toBe(1);
+      d();
+      expect(registry.items.length).toBe(3);
+    })
   });
 });

src/main/catalog/catalog-entity-registry.ts

@@ -19,12 +19,20 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+import { once } from "lodash";
 import { action, computed, IComputedValue, IObservableArray, makeObservable, observable } from "mobx";
 import { CatalogCategoryRegistry, catalogCategoryRegistry, CatalogEntity, CatalogEntityKindData } from "../../common/catalog";
-import { iter } from "../../common/utils";
+import { Disposer, iter } from "../../common/utils";
+
+export type EntityFilter = (entity: CatalogEntity) => any;
 
 export class CatalogEntityRegistry {
   protected sources = observable.map<string, IComputedValue<CatalogEntity[]>>();
+  protected filters = observable.set<EntityFilter>([
+    entity => this.categoryRegistry.getCategoryForEntity(entity)
+  ], {
+    deep: false,
+  });
 
   constructor(private categoryRegistry: CatalogCategoryRegistry) {
     makeObservable(this);
@@ -43,9 +51,13 @@ export class CatalogEntityRegistry {
   }
 
   @computed get items(): CatalogEntity[] {
-    const allItems = Array.from(iter.flatMap(this.sources.values(), source => source.get()));
-
-    return allItems.filter((entity) => this.categoryRegistry.getCategoryForEntity(entity) !== undefined);
+    return Array.from(
+      iter.reduce(
+        this.filters,
+        iter.filter,
+        iter.flatMap(this.sources.values(), source => source.get()),
+      )
+    );
   }
 
   getById<T extends CatalogEntity>(id: string): T | undefined {
@@ -53,7 +65,6 @@ export class CatalogEntityRegistry {
 
     if (item) return item as T;
 
-
     return undefined;
   }
 
@@ -66,6 +77,17 @@ export class CatalogEntityRegistry {
   getItemsByEntityClass<T extends CatalogEntity>({ apiVersion, kind }: CatalogEntityKindData): T[] {
     return this.getItemsForApiKind(apiVersion, kind);
   }
+
+  /**
+   * Add a new filter to the set of item filters
+   * @param fn The function that should return a truthy value if that entity should be sent currently "active"
+   * @returns A function to remove that filter
+   */
+  addCatalogFilter(fn: EntityFilter): Disposer {
+    this.filters.add(fn);
+
+    return once(() => void this.filters.delete(fn));
+  }
 }
 
 export const catalogEntityRegistry = new CatalogEntityRegistry(catalogCategoryRegistry);