feat: add support for the querying in the catalog client

Signed-off-by: benjdlambert <ben@blam.sh>

packages/catalog-client/src/testUtils/InMemoryCatalogClient.test.ts

@@ -683,6 +683,83 @@ describe('InMemoryCatalogClient', () => {
       ]);
     });
 
+    it('filters by predicate query', async () => {
+      const client = new InMemoryCatalogClient({ entities });
+      const result = await client.queryEntities({
+        query: { kind: 'CustomKind' },
+      });
+      expect(result.items).toEqual([entity1, entity3]);
+      expect(result.totalItems).toBe(2);
+    });
+
+    it('filters by predicate query with $all', async () => {
+      const client = new InMemoryCatalogClient({ entities });
+      const result = await client.queryEntities({
+        query: {
+          $all: [{ kind: 'CustomKind' }, { 'spec.type': 'service' }],
+        },
+      });
+      expect(result.items).toEqual([entity1, entity3]);
+    });
+
+    it('filters by predicate query with $any', async () => {
+      const client = new InMemoryCatalogClient({ entities });
+      const result = await client.queryEntities({
+        query: {
+          $any: [{ 'spec.type': 'service' }, { 'spec.type': 'website' }],
+        },
+      });
+      expect(result.items).toEqual([entity1, entity3, entity4]);
+    });
+
+    it('filters by predicate query with $not', async () => {
+      const client = new InMemoryCatalogClient({ entities });
+      const result = await client.queryEntities({
+        query: {
+          $all: [
+            { kind: 'CustomKind' },
+            { $not: { 'spec.lifecycle': 'production' } },
+          ],
+        },
+      });
+      expect(result.items).toEqual([]);
+    });
+
+    it('filters by predicate query with $in', async () => {
+      const client = new InMemoryCatalogClient({ entities });
+      const result = await client.queryEntities({
+        query: { 'spec.type': { $in: ['service', 'library'] } },
+      });
+      expect(result.items).toEqual([entity1, entity2, entity3]);
+    });
+
+    it('filters by predicate query with $exists', async () => {
+      const client = new InMemoryCatalogClient({ entities });
+      const result = await client.queryEntities({
+        query: { 'spec.lifecycle': { $exists: false } },
+      });
+      expect(result.items).toEqual([entity4]);
+    });
+
+    it('preserves query predicate through cursor pagination', async () => {
+      const client = new InMemoryCatalogClient({ entities });
+      const page1 = await client.queryEntities({
+        query: { kind: 'CustomKind' },
+        orderFields: { field: 'metadata.name', order: 'asc' },
+        limit: 1,
+      });
+      expect(page1.items.map(e => e.metadata.name)).toEqual(['e1']);
+      expect(page1.totalItems).toBe(2);
+      expect(page1.pageInfo.nextCursor).toBeDefined();
+
+      const page2 = await client.queryEntities({
+        cursor: page1.pageInfo.nextCursor!,
+        limit: 1,
+      });
+      expect(page2.items.map(e => e.metadata.name)).toEqual(['e3']);
+      expect(page2.pageInfo.nextCursor).toBeUndefined();
+    });
+
     it('throws InputError for invalid cursor', async () => {
       const client = new InMemoryCatalogClient({ entities });
       await expect(

packages/catalog-client/src/testUtils/InMemoryCatalogClient.ts

@@ -51,6 +51,7 @@ import {
   NotFoundError,
   NotImplementedError,
 } from '@backstage/errors';
+import { filterPredicateToFilterFunction } from '@backstage/filter-predicates';
 import lodash from 'lodash';
 // eslint-disable-next-line @backstage/no-relative-monorepo-imports
 import { traverse } from '../../../../plugins/catalog-backend/src/database/operations/stitcher/buildEntitySearch';
@@ -373,6 +374,7 @@ export class InMemoryCatalogClient implements CatalogApi {
   ): Promise<QueryEntitiesResponse> {
     // Decode query parameters from cursor or from the request directly
     let filter: EntityFilterQuery | undefined;
+    let query: Record<string, unknown> | undefined;
     let orderFields: EntityOrderQuery | undefined;
     let fullTextFilter: { term: string; fields?: string[] } | undefined;
     let offset: number;
@@ -386,12 +388,17 @@ export class InMemoryCatalogClient implements CatalogApi {
         throw new InputError('Invalid cursor');
       }
       filter = deserializeFilter(c.filter as any[]);
+      query = c.query as Record<string, unknown> | undefined;
       orderFields = c.orderFields as EntityOrderQuery | undefined;
       fullTextFilter = c.fullTextFilter as typeof fullTextFilter;
       offset = c.offset as number;
       limit = request.limit;
     } else {
       filter = request?.filter;
+      query =
+        request?.query && typeof request.query === 'object'
+          ? (request.query as Record<string, unknown>)
+          : undefined;
       orderFields = request?.orderFields;
       fullTextFilter = request?.fullTextFilter;
       offset = request?.offset ?? 0;
@@ -401,6 +408,11 @@ export class InMemoryCatalogClient implements CatalogApi {
     // Apply filter
     let items = this.#entities.filter(createFilter(filter));
 
+    // Apply predicate-based query filter
+    if (query) {
+      items = items.filter(filterPredicateToFilterFunction(query));
+    }
+
     // Apply full-text filter, defaulting to the sort field or metadata.uid
     if (fullTextFilter) {
       const orderFieldsList = orderFields ? [orderFields].flat() : [];
@@ -432,6 +444,7 @@ export class InMemoryCatalogClient implements CatalogApi {
 
     const cursorBase = {
       filter: serializeFilter(filter),
+      query,
       orderFields,
       fullTextFilter,
       totalItems,