feat(scaffolder): Moving the storage to more task based appraches, and creating preparers

packages/catalog-model/src/entity/Entity.ts

@@ -48,7 +48,7 @@ export type Entity = {
  * @see https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#objectmeta-v1-meta
  * @see https://kubernetes.io/docs/concepts/overview/working-with-objects/kubernetes-objects/
  */
-export type EntityMeta = {
+export type EntityMeta = Record<string, any> & {
   /**
    * A globally unique ID for the entity.
    *

packages/catalog-model/src/kinds/TemplateEntityV1alpha1.ts

@@ -26,6 +26,7 @@ export interface TemplateEntityV1alpha1 extends Entity {
   kind: typeof KIND;
   spec: {
     type: string;
+    path?: string;
   };
 }
 
@@ -39,6 +40,7 @@ export class TemplateEntityV1alpha1Policy implements EntityPolicy {
       spec: yup
         .object({
           type: yup.string().required().min(1),
+          path: yup.string(),
         })
         .required(),
     });

plugins/scaffolder-backend/src/scaffolder/index.ts

@@ -14,5 +14,5 @@
  * limitations under the License.
  */
 export * from './templater';
-
+export * from './prepare';
 export * from './templater/cookiecutter';

plugins/scaffolder-backend/src/scaffolder/prepare/index.ts

@@ -13,12 +13,5 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import type { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
-
-export type StorageBase = {
-  /**
-   *
-   * @param id
-   */
-  prepare(template: TemplateEntityV1alpha1): Promise<string>;
-};
+export * from './preparers';
+export * from './types';

plugins/scaffolder-backend/src/scaffolder/prepare/preparers.ts

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2020 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.
+ */
+
+import { PreparerBase, RemoteLocation, PreparerBuilder } from './types';
+import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
+
+export class Preparers implements PreparerBuilder {
+  private preparerMap = new Map<RemoteLocation, PreparerBase>();
+
+  register(key: RemoteLocation, processor: PreparerBase) {
+    this.preparerMap.set(key, processor);
+  }
+
+  get(template: TemplateEntityV1alpha1): PreparerBase {
+    const preparerKey = this.getPreparerKeyFromEntity(template);
+    const preparer = this.preparerMap.get(preparerKey);
+
+    if (!preparer) {
+      throw new Error(`No preparer registered for type ${preparerKey}`);
+    }
+
+    return preparer;
+  }
+
+  private getPreparerKeyFromEntity(
+    entity: TemplateEntityV1alpha1,
+  ): RemoteLocation {
+    const annotation =
+      entity.metadata.annotations?.['backstage.io/managed-by-location'] ?? '';
+    const [key] = annotation?.split(':');
+
+    if (!key) {
+      throw new Error('Failed to parse the location data');
+    }
+
+    return key as RemoteLocation;
+  }
+}

plugins/scaffolder-backend/src/scaffolder/prepare/types.ts

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2020 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.
+ */
+import type { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
+
+export type PreparerBase = {
+  /**
+   * Given an Entity definition from the Service Catalog, go and prepare a directory
+   * with contents from the remote location in temporary storage and return the path
+   * @param template The template entity from the Service Catalog
+   */
+  prepare(template: TemplateEntityV1alpha1): Promise<string>;
+};
+
+export type PreparerBuilder = {
+  register(key: RemoteLocation, preparer: PreparerBase): void;
+  get(key: TemplateEntityV1alpha1): PreparerBase;
+};
+
+export type RemoteLocation = 'file';

plugins/scaffolder-backend/src/service/router.ts

@@ -17,10 +17,11 @@
 import { Logger } from 'winston';
 import Router from 'express-promise-router';
 import express from 'express';
-import { StorageBase, TemplaterBase } from '../scaffolder';
+import { PreparerBuilder, TemplaterBase } from '../scaffolder';
+import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 
 export interface RouterOptions {
-  storage: StorageBase;
+  preparers: PreparerBuilder;
   templater: TemplaterBase;
   logger: Logger;
 }
@@ -29,22 +30,43 @@ export async function createRouter(
   options: RouterOptions,
 ): Promise<express.Router> {
   const router = Router();
-  const { storage, templater, logger: parentLogger } = options;
+  const { preparers, templater, logger: parentLogger } = options;
   const logger = parentLogger.child({ plugin: 'scaffolder' });
 
-  router
-    .get('/v1/templates', async (_, res) => {
-      const templates = await storage.list();
-      res.status(200).json(templates);
-    })
-    .post('/v1/jobs', async (_, res) => {
-      // TODO(blam): Actually make this function work
-      const mock = 'templateid';
-      res.status(201).json({ accepted: true });
+  router.post('/v1/jobs', async (_, res) => {
+    // TODO(blam): Actually make this function work
+    // res.status(201).json({ accepted: true });
 
-      const path = await storage.prepare(mock);
-      await templater.run({ directory: path, values: { componentId: 'test' } });
-    });
+    const mockEntity: TemplateEntityV1alpha1 = {
+      apiVersion: 'backstage.io/v1alpha1',
+      kind: 'Template',
+      metadata: {
+        annotations: {
+          'backstage.io/managed-by-location':
+            'file:/Users/blam/dev/spotify/backstage/plugins/scaffolder-backend/sample-templates/react-ssr-template/template.yaml',
+        },
+        name: 'react-ssr-template',
+        title: 'React SSR Template',
+        description:
+          'Next.js application skeleton for creating isomorphic web applications.',
+        uid: '7357f4c5-aa58-4a1e-9670-18931eef771f',
+        etag: 'YWUxZWQyY2EtZDkxMC00MDM0LWI0ODAtMDgwMWY0YzdlMWIw',
+        generation: 1,
+      },
+      spec: {
+        type: 'cookiecutter',
+        path: '.',
+      },
+    };
+
+    // fetch the entity from service catalog here.
+    const preparer = preparers.get(mockEntity);
+
+    //
+    const path = await preparer.prepare(mockEntity);
+
+    await templater.run({ directory: path, values: { componentId: 'test' } });
+  });
 
   const app = express();
   app.set('logger', logger);