From 53eb5e61e31ed470d5c8acf5c33328aeae1c9198 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Tue, 13 Oct 2020 19:13:05 +0530
Subject: [PATCH 01/12] feat: Implement CatalogEntityClient, mainly to get
 Template entity from template name

---
 .../src/lib/catalog/CatalogEntityClient.ts    | 70 +++++++++++++++++++
 .../src/lib/catalog/index.ts                  | 16 +++++
 2 files changed, 86 insertions(+)
 create mode 100644 plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
 create mode 100644 plugins/scaffolder-backend/src/lib/catalog/index.ts

diff --git a/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
new file mode 100644
index 0000000000..48856e7783
--- /dev/null
+++ b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
@@ -0,0 +1,70 @@
+/*
+ * 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 fetch from 'node-fetch';
+import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
+import {
+  ConflictError,
+  NotFoundError,
+  PluginEndpointDiscovery,
+} from '@backstage/backend-common';
+
+/**
+ * A catalog client tailored for reading out entity data from the catalog.
+ */
+export class CatalogEntityClient {
+  private readonly discovery: PluginEndpointDiscovery;
+
+  constructor(options: { discovery: PluginEndpointDiscovery }) {
+    this.discovery = options.discovery;
+  }
+
+  /**
+   * Looks up a single template using a template name.
+   *
+   * Throws a NotFoundError or ConflictError if 0 or multiple templates are found.
+   */
+  async findTemplate(templateName: string): Promise<TemplateEntityV1alpha1> {
+    const params = new URLSearchParams();
+    params.append('kind', 'Template');
+
+    params.append('metadata.name', templateName);
+
+    const baseUrl = await this.discovery.getBaseUrl('catalog');
+    const response = await fetch(`${baseUrl}/entities?${params}`);
+
+    if (!response.ok) {
+      const text = await response.text();
+      throw new Error(
+        `Request failed with ${response.status} ${response.statusText}, ${text}`,
+      );
+    }
+
+    const templates: TemplateEntityV1alpha1[] = await response.json();
+
+    if (templates.length !== 1) {
+      if (templates.length > 1) {
+        throw new ConflictError(
+          'Templates lookup resulted in multiple matches',
+        );
+      } else {
+        throw new NotFoundError('Template not found');
+      }
+    }
+
+    return templates[0];
+  }
+}
diff --git a/plugins/scaffolder-backend/src/lib/catalog/index.ts b/plugins/scaffolder-backend/src/lib/catalog/index.ts
new file mode 100644
index 0000000000..a8de546e00
--- /dev/null
+++ b/plugins/scaffolder-backend/src/lib/catalog/index.ts
@@ -0,0 +1,16 @@
+/*
+ * 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.
+ */
+export { CatalogEntityClient } from './CatalogEntityClient';

From a24b6577212edb80009ac79b8121de12a86278b5 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Tue, 13 Oct 2020 19:14:49 +0530
Subject: [PATCH 02/12] feat: use CatalogEntityClient

---
 plugins/scaffolder-backend/package.json       |  3 ++-
 .../scaffolder-backend/src/service/router.ts  | 23 +++++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/plugins/scaffolder-backend/package.json b/plugins/scaffolder-backend/package.json
index 66d6457333..fac30df196 100644
--- a/plugins/scaffolder-backend/package.json
+++ b/plugins/scaffolder-backend/package.json
@@ -44,7 +44,8 @@
     "nodegit": "0.27.0",
     "uuid": "^8.2.0",
     "winston": "^3.2.1",
-    "yaml": "^1.10.0"
+    "yaml": "^1.10.0",
+    "node-fetch": "^2.6.1"
   },
   "devDependencies": {
     "@backstage/cli": "^0.1.1-alpha.25",
diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index f61d2566b9..a556916df0 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -14,8 +14,12 @@
  * limitations under the License.
  */
 
+import {
+  loadBackendConfig,
+  SingleHostDiscovery,
+} from '@backstage/backend-common';
+import { JsonValue, ConfigReader } from '@backstage/config';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
-import { JsonValue } from '@backstage/config';
 import Docker from 'dockerode';
 import express from 'express';
 import Router from 'express-promise-router';
@@ -28,6 +32,7 @@ import {
   TemplaterBuilder,
   PublisherBuilder,
 } from '../scaffolder';
+import { CatalogEntityClient } from '../lib/catalog';
 import { validate, ValidatorResult } from 'jsonschema';
 
 export interface RouterOptions {
@@ -56,6 +61,10 @@ export async function createRouter(
   const logger = parentLogger.child({ plugin: 'scaffolder' });
   const jobProcessor = new JobProcessor();
 
+  const config = ConfigReader.fromConfigs(await loadBackendConfig());
+  const discovery = SingleHostDiscovery.fromConfig(config);
+  const entityClient = new CatalogEntityClient({ discovery });
+
   router
     .get('/v1/job/:jobId', ({ params }, res) => {
       const job = jobProcessor.get(params.jobId);
@@ -81,14 +90,24 @@ export async function createRouter(
       });
     })
     .post('/v1/jobs', async (req, res) => {
-      const template: TemplateEntityV1alpha1 = req.body.template;
+      const templateName: string = req.body.templateName;
       const values: RequiredTemplateValues & Record<string, JsonValue> =
         req.body.values;
 
+      let template: TemplateEntityV1alpha1;
+      try {
+        template = await entityClient.findTemplate(templateName);
+      } catch (e) {
+        // help me here
+        res.status(400).json({ errors: e });
+        return;
+      }
+
       const validationResult: ValidatorResult = validate(
         values,
         template.spec.schema,
       );
+
       if (!validationResult.valid) {
         res.status(400).json({ errors: validationResult.errors });
         return;

From 91e425fdabb5a024d81114ab643655422e71fb38 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Tue, 13 Oct 2020 19:16:22 +0530
Subject: [PATCH 03/12] feat: Pass entity unique id to POST body of /v1/jobs
 instead of entire entity

---
 plugins/scaffolder/src/api.ts                          | 10 +++-------
 .../src/components/TemplatePage/TemplatePage.tsx       |  2 +-
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/plugins/scaffolder/src/api.ts b/plugins/scaffolder/src/api.ts
index f58c8e68d1..ca52418e92 100644
--- a/plugins/scaffolder/src/api.ts
+++ b/plugins/scaffolder/src/api.ts
@@ -15,7 +15,6 @@
  */
 
 import { createApiRef, DiscoveryApi } from '@backstage/core';
-import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 
 export const scaffolderApiRef = createApiRef<ScaffolderApi>({
   id: 'plugin.scaffolder.service',
@@ -33,20 +32,17 @@ export class ScaffolderApi {
    * Executes the scaffolding of a component, given a template and its
    * parameter values.
    *
-   * @param template Template entity for the scaffolder to use. New project is going to be created out of this template.
+   * @param templateName Template name for the scaffolder to use. New project is going to be created out of this template.
    * @param values Parameters for the template, e.g. name, description
    */
-  async scaffold(
-    template: TemplateEntityV1alpha1,
-    values: Record<string, any>,
-  ) {
+  async scaffold(templateName: string, values: Record<string, any>) {
     const url = `${await this.discoveryApi.getBaseUrl('scaffolder')}/v1/jobs`;
     const response = await fetch(url, {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
       },
-      body: JSON.stringify({ template, values: { ...values } }),
+      body: JSON.stringify({ templateName, values: { ...values } }),
     });
 
     if (response.status !== 201) {
diff --git a/plugins/scaffolder/src/components/TemplatePage/TemplatePage.tsx b/plugins/scaffolder/src/components/TemplatePage/TemplatePage.tsx
index e68c795bd6..6c71a2eab1 100644
--- a/plugins/scaffolder/src/components/TemplatePage/TemplatePage.tsx
+++ b/plugins/scaffolder/src/components/TemplatePage/TemplatePage.tsx
@@ -97,7 +97,7 @@ export const TemplatePage = () => {
 
   const handleCreate = async () => {
     try {
-      const job = await scaffolderApi.scaffold(template!, formState);
+      const job = await scaffolderApi.scaffold(templateName, formState);
       setJobId(job);
     } catch (e) {
       errorApi.post(e);

From c5acbbb8c42114338747935d7c044898f6578bd0 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Fri, 23 Oct 2020 23:32:10 +0530
Subject: [PATCH 04/12] chore: replace node-fetch => cross-fetch

---
 plugins/scaffolder-backend/package.json                         | 2 +-
 .../scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts   | 2 +-
 yarn.lock                                                       | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/plugins/scaffolder-backend/package.json b/plugins/scaffolder-backend/package.json
index fac30df196..e87f86961e 100644
--- a/plugins/scaffolder-backend/package.json
+++ b/plugins/scaffolder-backend/package.json
@@ -45,7 +45,7 @@
     "uuid": "^8.2.0",
     "winston": "^3.2.1",
     "yaml": "^1.10.0",
-    "node-fetch": "^2.6.1"
+    "cross-fetch": "^3.0.6"
   },
   "devDependencies": {
     "@backstage/cli": "^0.1.1-alpha.25",
diff --git a/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
index 48856e7783..84676b63fe 100644
--- a/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
+++ b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import fetch from 'node-fetch';
+import fetch from 'cross-fetch';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 import {
   ConflictError,
diff --git a/yarn.lock b/yarn.lock
index 4832a549b8..2c7c609835 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -9021,7 +9021,7 @@ cross-env@^7.0.0:
   dependencies:
     cross-spawn "^7.0.1"
 
-cross-fetch@3.0.6, cross-fetch@^3.0.4, cross-fetch@^3.0.5:
+cross-fetch@3.0.6, cross-fetch@^3.0.4, cross-fetch@^3.0.5, cross-fetch@^3.0.6:
   version "3.0.6"
   resolved "https://registry.npmjs.org/cross-fetch/-/cross-fetch-3.0.6.tgz#3a4040bc8941e653e0e9cf17f29ebcd177d3365c"
   integrity sha512-KBPUbqgFjzWlVcURG+Svp9TlhA5uliYtiNx/0r8nv0pdypeQCRJ9IaSIc3q/x3q8t3F75cHuwxVql1HFGHCNJQ==

From 8440f8f91be240cf96c7447262547adb653ba410 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Tue, 27 Oct 2020 10:02:56 +0530
Subject: [PATCH 05/12] feat: load config directly, #2976

---
 plugins/scaffolder-backend/src/service/router.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index a556916df0..bf1eeae8dd 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -17,8 +17,9 @@
 import {
   loadBackendConfig,
   SingleHostDiscovery,
+  getRootLogger,
 } from '@backstage/backend-common';
-import { JsonValue, ConfigReader } from '@backstage/config';
+import { JsonValue } from '@backstage/config';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 import Docker from 'dockerode';
 import express from 'express';
@@ -61,7 +62,10 @@ export async function createRouter(
   const logger = parentLogger.child({ plugin: 'scaffolder' });
   const jobProcessor = new JobProcessor();
 
-  const config = ConfigReader.fromConfigs(await loadBackendConfig());
+  const config = await loadBackendConfig({
+    argv: process.argv,
+    logger: getRootLogger(),
+  });
   const discovery = SingleHostDiscovery.fromConfig(config);
   const entityClient = new CatalogEntityClient({ discovery });
 

From f2a9bba5e27ad2e2ec29d3fdccec303d8de1e808 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Tue, 27 Oct 2020 10:53:40 +0530
Subject: [PATCH 06/12] feat: update related to #3066

---
 .../src/lib/catalog/CatalogEntityClient.ts           | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
index 84676b63fe..4541f03a4a 100644
--- a/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
+++ b/plugins/scaffolder-backend/src/lib/catalog/CatalogEntityClient.ts
@@ -38,13 +38,15 @@ export class CatalogEntityClient {
    * Throws a NotFoundError or ConflictError if 0 or multiple templates are found.
    */
   async findTemplate(templateName: string): Promise<TemplateEntityV1alpha1> {
-    const params = new URLSearchParams();
-    params.append('kind', 'Template');
-
-    params.append('metadata.name', templateName);
+    const conditions = [
+      'kind=template',
+      `metadata.name=${encodeURIComponent(templateName)}`,
+    ];
 
     const baseUrl = await this.discovery.getBaseUrl('catalog');
-    const response = await fetch(`${baseUrl}/entities?${params}`);
+    const response = await fetch(
+      `${baseUrl}/entities?filter=${conditions.join(',')}`,
+    );
 
     if (!response.ok) {
       const text = await response.text();

From 097e3d222a61889c029c109d9693f8ec298ada0d Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Wed, 28 Oct 2020 10:54:38 +0530
Subject: [PATCH 07/12] fix: error handling

---
 plugins/scaffolder-backend/src/service/router.ts | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index 83a0cbd398..efe8ee46f6 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -115,10 +115,8 @@ export async function createRouter(
       let template: TemplateEntityV1alpha1;
       try {
         template = await entityClient.findTemplate(templateName);
-      } catch (e) {
-        // help me here
-        res.status(400).json({ errors: e });
-        return;
+      } catch (err) {
+        throw err;
       }
 
       const validationResult: ValidatorResult = validate(

From 55af83a78a9ce8c0591728c2fec13dbdd2d39e9a Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Thu, 29 Oct 2020 14:33:09 +0530
Subject: [PATCH 08/12] chore: move entityClient to createPlugin, mock
 entityClient in tests

---
 packages/backend/src/plugins/scaffolder.ts    |  6 ++
 plugins/scaffolder-backend/src/index.ts       |  1 +
 .../src/service/router.test.ts                | 91 ++++++++++---------
 .../scaffolder-backend/src/service/router.ts  |  5 +-
 4 files changed, 59 insertions(+), 44 deletions(-)

diff --git a/packages/backend/src/plugins/scaffolder.ts b/packages/backend/src/plugins/scaffolder.ts
index 6eacd143c1..5d36d508a5 100644
--- a/packages/backend/src/plugins/scaffolder.ts
+++ b/packages/backend/src/plugins/scaffolder.ts
@@ -21,7 +21,9 @@ import {
   Publishers,
   CreateReactAppTemplater,
   Templaters,
+  CatalogEntityClient,
 } from '@backstage/plugin-scaffolder-backend';
+import { SingleHostDiscovery } from '@backstage/backend-common';
 import type { PluginEnvironment } from '../types';
 import Docker from 'dockerode';
 
@@ -40,6 +42,9 @@ export default async function createPlugin({
 
   const dockerClient = new Docker();
 
+  const discovery = SingleHostDiscovery.fromConfig(config);
+  const entityClient = new CatalogEntityClient({ discovery });
+
   return await createRouter({
     preparers,
     templaters,
@@ -47,5 +52,6 @@ export default async function createPlugin({
     logger,
     config,
     dockerClient,
+    entityClient,
   });
 }
diff --git a/plugins/scaffolder-backend/src/index.ts b/plugins/scaffolder-backend/src/index.ts
index c461bfede6..28e6a2b24c 100644
--- a/plugins/scaffolder-backend/src/index.ts
+++ b/plugins/scaffolder-backend/src/index.ts
@@ -16,3 +16,4 @@
 
 export * from './scaffolder';
 export * from './service/router';
+export * from './lib/catalog';
diff --git a/plugins/scaffolder-backend/src/service/router.test.ts b/plugins/scaffolder-backend/src/service/router.test.ts
index fae7ee8beb..c2b60a2040 100644
--- a/plugins/scaffolder-backend/src/service/router.test.ts
+++ b/plugins/scaffolder-backend/src/service/router.test.ts
@@ -35,6 +35,10 @@ import Docker from 'dockerode';
 
 jest.mock('dockerode');
 
+const generateEntityClient: any = (template: any) => ({
+  findTemplate: () => Promise.resolve(template),
+});
+
 describe('createRouter - working directory', () => {
   const mockPrepare = jest.fn();
   const mockPreparers = new Preparers();
@@ -74,6 +78,8 @@ describe('createRouter - working directory', () => {
     },
   };
 
+  const mockedEntityClient = generateEntityClient(template);
+
   it('should throw an error when working directory does not exist or is not writable', async () => {
     mockAccess.mockImplementation(() => {
       throw new Error('access error');
@@ -87,6 +93,7 @@ describe('createRouter - working directory', () => {
         publishers: new Publishers(),
         config: ConfigReader.fromConfigs([workDirConfig('/path')]),
         dockerClient: new Docker(),
+        entityClient: mockedEntityClient,
       }),
     ).rejects.toThrow('access error');
   });
@@ -99,11 +106,12 @@ describe('createRouter - working directory', () => {
       publishers: new Publishers(),
       config: ConfigReader.fromConfigs([workDirConfig('/path')]),
       dockerClient: new Docker(),
+      entityClient: mockedEntityClient,
     });
 
     const app = express().use(router);
     await request(app).post('/v1/jobs').send({
-      template,
+      templateName: '',
       values: {},
     });
 
@@ -121,11 +129,12 @@ describe('createRouter - working directory', () => {
       publishers: new Publishers(),
       config: ConfigReader.fromConfigs([]),
       dockerClient: new Docker(),
+      entityClient: mockedEntityClient,
     });
 
     const app = express().use(router);
     await request(app).post('/v1/jobs').send({
-      template,
+      templateName: '',
       values: {},
     });
 
@@ -137,6 +146,43 @@ describe('createRouter - working directory', () => {
 
 describe('createRouter', () => {
   let app: express.Express;
+  const template = {
+    apiVersion: 'backstage.io/v1alpha1',
+    kind: 'Template',
+    metadata: {
+      description: 'Create a new CRA website project',
+      name: 'create-react-app-template',
+      tags: ['experimental', 'react', 'cra'],
+      title: 'Create React App Template',
+    },
+    spec: {
+      owner: 'web@example.com',
+      path: '.',
+      schema: {
+        properties: {
+          component_id: {
+            description: 'Unique name of the component',
+            title: 'Name',
+            type: 'string',
+          },
+          description: {
+            description: 'Description of the component',
+            title: 'Description',
+            type: 'string',
+          },
+          use_typescript: {
+            default: true,
+            description: 'Include typescript',
+            title: 'Use Typescript',
+            type: 'boolean',
+          },
+        },
+        required: ['component_id', 'use_typescript'],
+      },
+      templater: 'cra',
+      type: 'website',
+    },
+  };
 
   beforeAll(async () => {
     const router = await createRouter({
@@ -146,6 +192,7 @@ describe('createRouter', () => {
       publishers: new Publishers(),
       config: ConfigReader.fromConfigs([]),
       dockerClient: new Docker(),
+      entityClient: generateEntityClient(template),
     });
     app = express().use(router);
   });
@@ -155,47 +202,9 @@ describe('createRouter', () => {
   });
 
   describe('POST /v1/jobs', () => {
-    const template = {
-      apiVersion: 'backstage.io/v1alpha1',
-      kind: 'Template',
-      metadata: {
-        description: 'Create a new CRA website project',
-        name: 'create-react-app-template',
-        tags: ['experimental', 'react', 'cra'],
-        title: 'Create React App Template',
-      },
-      spec: {
-        owner: 'web@example.com',
-        path: '.',
-        schema: {
-          properties: {
-            component_id: {
-              description: 'Unique name of the component',
-              title: 'Name',
-              type: 'string',
-            },
-            description: {
-              description: 'Description of the component',
-              title: 'Description',
-              type: 'string',
-            },
-            use_typescript: {
-              default: true,
-              description: 'Include typescript',
-              title: 'Use Typescript',
-              type: 'boolean',
-            },
-          },
-          required: ['component_id', 'use_typescript'],
-        },
-        templater: 'cra',
-        type: 'website',
-      },
-    };
-
     it('rejects template values which do not match the template schema definition', async () => {
       const response = await request(app).post('/v1/jobs').send({
-        template,
+        templateName: '',
         values: {},
       });
 
diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index efe8ee46f6..e4d3d5c45a 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { SingleHostDiscovery } from '@backstage/backend-common';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 import { Config, JsonValue } from '@backstage/config';
 import fs from 'fs-extra';
@@ -41,6 +40,7 @@ export interface RouterOptions {
   logger: Logger;
   config: Config;
   dockerClient: Docker;
+  entityClient: CatalogEntityClient;
 }
 
 export async function createRouter(
@@ -56,13 +56,12 @@ export async function createRouter(
     logger: parentLogger,
     config,
     dockerClient,
+    entityClient,
   } = options;
 
   const logger = parentLogger.child({ plugin: 'scaffolder' });
   const jobProcessor = new JobProcessor();
 
-  const discovery = SingleHostDiscovery.fromConfig(config);
-  const entityClient = new CatalogEntityClient({ discovery });
   let workingDirectory: string;
   if (config.has('backend.workingDirectory')) {
     workingDirectory = config.getString('backend.workingDirectory');

From 1ddcf191dbf5f0280383e3bb20f251016ed14889 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Thu, 29 Oct 2020 14:46:55 +0530
Subject: [PATCH 09/12] fix: use entityClient in create-app package

---
 .../default-app/packages/backend/src/plugins/scaffolder.ts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts b/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts
index 8de15920e9..2dc69feb45 100644
--- a/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts
+++ b/packages/create-app/templates/default-app/packages/backend/src/plugins/scaffolder.ts
@@ -11,7 +11,9 @@ import {
   CreateReactAppTemplater,
   Templaters,
   RepoVisibilityOptions,
+  CatalogEntityClient,
 } from '@backstage/plugin-scaffolder-backend';
+import { SingleHostDiscovery } from '@backstage/backend-common';
 import { Octokit } from '@octokit/rest';
 import { Gitlab } from '@gitbeaker/node';
 import type { PluginEnvironment } from '../types';
@@ -97,6 +99,10 @@ export default async function createPlugin({
   }
 
   const dockerClient = new Docker();
+
+  const discovery = SingleHostDiscovery.fromConfig(config);
+  const entityClient = new CatalogEntityClient({ discovery });
+
   return await createRouter({
     preparers,
     templaters,
@@ -104,5 +110,6 @@ export default async function createPlugin({
     logger,
     config,
     dockerClient,
+    entityClient,
   });
 }

From 364939e5e3dee6511e62185a6d492a2f904e8f4a Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Thu, 29 Oct 2020 14:54:30 +0530
Subject: [PATCH 10/12] chore: remove try/catch

---
 plugins/scaffolder-backend/src/service/router.ts | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index e4d3d5c45a..2dc6a794fb 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 import { Config, JsonValue } from '@backstage/config';
 import fs from 'fs-extra';
 import Docker from 'dockerode';
@@ -111,12 +110,7 @@ export async function createRouter(
       const values: RequiredTemplateValues & Record<string, JsonValue> =
         req.body.values;
 
-      let template: TemplateEntityV1alpha1;
-      try {
-        template = await entityClient.findTemplate(templateName);
-      } catch (err) {
-        throw err;
-      }
+      const template = await entityClient.findTemplate(templateName);
 
       const validationResult: ValidatorResult = validate(
         values,

From 59166e5ec2b98e6389ba19c1353122c32c150a84 Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Mon, 2 Nov 2020 22:19:56 +0530
Subject: [PATCH 11/12] chore: run changeset

---
 .changeset/weak-otters-love.md | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 .changeset/weak-otters-love.md

diff --git a/.changeset/weak-otters-love.md b/.changeset/weak-otters-love.md
new file mode 100644
index 0000000000..fb4ac19d3a
--- /dev/null
+++ b/.changeset/weak-otters-love.md
@@ -0,0 +1,6 @@
+---
+'@backstage/plugin-scaffolder': minor
+'@backstage/plugin-scaffolder-backend': minor
+---
+
+Scaffolder's API `/v1/jobs` will accept `templateName` instead of `template` Entity.

From 240036496013d4cb0c52dce9d47d3548705e7a8f Mon Sep 17 00:00:00 2001
From: Marvin9 <marvinduff97@gmail.com>
Date: Mon, 2 Nov 2020 22:48:44 +0530
Subject: [PATCH 12/12] chore: mention entityClient as an additional option of
 createRouter

---
 .changeset/weak-otters-love.md | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/.changeset/weak-otters-love.md b/.changeset/weak-otters-love.md
index fb4ac19d3a..2c273e067b 100644
--- a/.changeset/weak-otters-love.md
+++ b/.changeset/weak-otters-love.md
@@ -3,4 +3,14 @@
 '@backstage/plugin-scaffolder-backend': minor
 ---
 
-Scaffolder's API `/v1/jobs` will accept `templateName` instead of `template` Entity.
+`createRouter` of scaffolder backend will now require additional option as `entityClient` which could be generated by `CatalogEntityClient` in `plugin-scaffolder-backend` package. Here is example to generate `entityClient`.
+
+```js
+import { CatalogEntityClient } from '@backstage/plugin-scaffolder-backend';
+import { SingleHostDiscovery } from '@backstage/backend-common';
+
+const discovery = SingleHostDiscovery.fromConfig(config);
+const entityClient = new CatalogEntityClient({ discovery });
+```
+
+- Scaffolder's API `/v1/jobs` will accept `templateName` instead of `template` Entity.