compute all facets in one go

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/slow-singers-jump.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-backend': minor
+---
+
+Fetch all facets in a single database query

plugins/catalog-backend/src/service/DefaultEntitiesCatalog.test.ts

@@ -2060,6 +2060,50 @@ describe('DefaultEntitiesCatalog', () => {
         });
       },
     );
+
+    it.each(databases.eachSupportedId())(
+      'works with a mixture of present and missing facets, %p',
+      async databaseId => {
+        await createDatabase(databaseId);
+
+        await addEntityToSearch({
+          apiVersion: 'a',
+          kind: 'k',
+          metadata: {
+            name: 'one',
+          },
+          spec: {},
+        });
+        await addEntityToSearch({
+          apiVersion: 'a',
+          kind: 'k',
+          metadata: {
+            name: 'two',
+          },
+          spec: {},
+        });
+        const catalog = new DefaultEntitiesCatalog({
+          database: knex,
+          logger: mockServices.logger.mock(),
+          stitcher,
+        });
+
+        await expect(
+          catalog.facets({
+            facets: ['metadata.name', 'missing'],
+            credentials: mockCredentials.none(),
+          }),
+        ).resolves.toEqual({
+          facets: {
+            'metadata.name': expect.arrayContaining([
+              { value: 'one', count: 1 },
+              { value: 'two', count: 1 },
+            ]),
+            missing: [],
+          },
+        });
+      },
+    );
   });
 });
 

plugins/catalog-backend/src/service/DefaultEntitiesCatalog.ts

@@ -720,26 +720,40 @@ export class DefaultEntitiesCatalog implements EntitiesCatalog {
   }
 
   async facets(request: EntityFacetsRequest): Promise<EntityFacetsResponse> {
+    const query = this.database<DbSearchRow>('search')
+      .whereIn(
+        'search.key',
+        request.facets.map(f => f.toLocaleLowerCase('en-US')),
+      )
+      .whereNotNull('search.original_value')
+      .select({
+        facet: 'search.key',
+        value: 'search.original_value',
+        count: this.database.raw('count(*)'),
+      })
+      .groupBy(['search.key', 'search.original_value']);
+
+    if (request.filter) {
+      parseFilter(
+        request.filter,
+        query,
+        this.database,
+        false,
+        'search.entity_id',
+      );
+    }
+
+    const rows = await query;
+
     const facets: EntityFacetsResponse['facets'] = {};
-    const db = this.database;
-
     for (const facet of request.facets) {
-      const dbQuery = db<DbSearchRow>('search')
-        .where('search.key', facet.toLocaleLowerCase('en-US'))
-        .whereNotNull('search.original_value')
-        .select({ value: 'search.original_value', count: db.raw('count(*)') })
-        .groupBy('search.original_value');
-
-      if (request?.filter) {
-        parseFilter(request.filter, dbQuery, db, false, 'search.entity_id');
-      }
-
-      const result = await dbQuery;
-
-      facets[facet] = result.map(data => ({
-        value: String(data.value),
-        count: Number(data.count),
-      }));
+      const facetLowercase = facet.toLocaleLowerCase('en-US');
+      facets[facet] = rows
+        .filter(row => row.facet === facetLowercase)
+        .map(row => ({
+          value: String(row.value),
+          count: Number(row.count),
+        }));
     }
 
     return { facets };