Introduce techdocs metadata in techdocs-common

* Add TechdocsMetadata type in backend plugin endpoint
 * Introduce TechDocsMetadata type in frontend
 * Add changeset
 * Remove old thennable metadata resp
 * Address PR feedback
  - Remove explicit type annotation on TechDocsMetadata
  - Reintroduce res.send instead of throwing an error
  - Change logger info to logger error
 * Add TechDocsMetadata type in frontend plugin
 * Commit yarn.lock
 * Introduce JSON5 and remove parsing in local pub
Signed-off-by: Matei David <matei.david.35@gmail.com>

plugins/techdocs/src/api.ts

@@ -16,6 +16,7 @@
 
 import { createApiRef } from '@backstage/core';
 import { EntityName } from '@backstage/catalog-model';
+import { TechDocsMetadata } from './types';
 
 export const techdocsStorageApiRef = createApiRef<TechDocsStorageApi>({
   id: 'plugin.techdocs.storageservice',
@@ -33,7 +34,7 @@ export interface TechDocsStorage {
 }
 
 export interface TechDocs {
-  getTechDocsMetadata(entityId: EntityName): Promise<string>;
+  getTechDocsMetadata(entityId: EntityName): Promise<TechDocsMetadata>;
   getEntityMetadata(entityId: EntityName): Promise<string>;
 }
 

plugins/techdocs/src/reader/components/TechDocsPageHeader.tsx

@@ -19,12 +19,13 @@ import { AsyncState } from 'react-use/lib/useAsync';
 import CodeIcon from '@material-ui/icons/Code';
 import { EntityName } from '@backstage/catalog-model';
 import { Header, HeaderLabel, Link } from '@backstage/core';
+import { TechDocsMetadata } from '../../types';
 
 type TechDocsPageHeaderProps = {
   entityId: EntityName;
   metadataRequest: {
     entity: AsyncState<any>;
-    techdocs: AsyncState<any>;
+    techdocs: AsyncState<TechDocsMetadata>;
   };
 };
 

plugins/techdocs/src/types.ts

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2021 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export type TechDocsMetadata = {
+  site_name: string;
+  site_description: string;
+};