From bc15e7a7103cb0e49d5ea6e7eb01919feec2e1ad Mon Sep 17 00:00:00 2001
From: Ivan Shmidt <bahoc47@gmail.com>
Date: Tue, 23 Jun 2020 11:56:56 +0200
Subject: [PATCH 1/6] feat(scaffolder): cookiecutter templater wip

Co-authored-by: Ben Lambert <ben@blam.sh>
---
 plugins/scaffolder-backend/package.json       |  1 +
 .../hooks/post_gen_project.sh                 | 17 ++++++----------
 .../hooks/pre_gen_project.sh                  |  9 ---------
 .../package.json                              |  2 +-
 plugins/scaffolder-backend/scripts/Dockerfile | 11 ++++++++++
 .../src/scaffolder/templater/cookiecutter.ts  | 20 +++++++++++++++++--
 .../scaffolder-backend/src/service/router.ts  |  9 ++++++---
 yarn.lock                                     |  7 +++++++
 8 files changed, 50 insertions(+), 26 deletions(-)
 delete mode 100644 plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/pre_gen_project.sh
 create mode 100644 plugins/scaffolder-backend/scripts/Dockerfile

diff --git a/plugins/scaffolder-backend/package.json b/plugins/scaffolder-backend/package.json
index 0edf7a8fe9..e85a65e744 100644
--- a/plugins/scaffolder-backend/package.json
+++ b/plugins/scaffolder-backend/package.json
@@ -37,6 +37,7 @@
   },
   "devDependencies": {
     "@backstage/cli": "^0.1.1-alpha.9",
+    "@types/dockerode": "^2.5.32",
     "@types/fs-extra": "^9.0.1",
     "@types/supertest": "^2.0.8",
     "supertest": "^4.0.2",
diff --git a/plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/post_gen_project.sh b/plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/post_gen_project.sh
index 033a102fed..75c35f2034 100644
--- a/plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/post_gen_project.sh
+++ b/plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/post_gen_project.sh
@@ -1,12 +1,7 @@
-#!/bin/bash
+#!/bin/sh
 
-# package name is "__component_id__" so that yarn doesn't throw an error
-# about invalid characters when running yarn commands. here we replace it with the actual name
-sed -i -e "s/__component_id__/{{ cookiecutter.component_id }}/g" package.json
-
-# node_modules was moved out of the template folder, during the pre_gen hook,
-# to avoid cookie_cutter from copying all of them. time to move it back
-mv ../../node_modules.tmp ../../\{\{cookiecutter.component_id\}\}/node_modules 2>/dev/null ||:
-
-# move back the build directory that was moved out in the pre_gen hook (if it exists)
-mv ../../build.tmp ../../\{\{cookiecutter.component_id\}\}/build 2>/dev/null ||:
+# Move all template files to the root folder
+mv ./* ../
+cd ..
+rm -rf {{cookiecutter.component_id}}
+# # # # # # # # 
diff --git a/plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/pre_gen_project.sh b/plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/pre_gen_project.sh
deleted file mode 100644
index 142fda9ad9..0000000000
--- a/plugins/scaffolder-backend/sample-templates/react-ssr-template/hooks/pre_gen_project.sh
+++ /dev/null
@@ -1,9 +0,0 @@
-#!/bin/bash
-
-# no way to ignore files in cookiecutter, so move node_modules out while building
-# to avoid cookiecutter from copying all of them
-mv ../../\{\{cookiecutter.component_id\}\}/node_modules ../../node_modules.tmp  2>/dev/null ||:
-
-# cookicutter really doesn't like the next.js build directory, so if the app has
-# been built from inside the template folder, that folders needs to be moved out as well
-mv ../../\{\{cookiecutter.component_id\}\}/build ../../build.tmp  2>/dev/null ||:
diff --git a/plugins/scaffolder-backend/sample-templates/react-ssr-template/{{cookiecutter.component_id}}/package.json b/plugins/scaffolder-backend/sample-templates/react-ssr-template/{{cookiecutter.component_id}}/package.json
index a0ae26e267..6ae3e63a17 100644
--- a/plugins/scaffolder-backend/sample-templates/react-ssr-template/{{cookiecutter.component_id}}/package.json
+++ b/plugins/scaffolder-backend/sample-templates/react-ssr-template/{{cookiecutter.component_id}}/package.json
@@ -1,5 +1,5 @@
 {
-  "name": "__component_id__",
+  "name": "{{ cookiecutter.component_id }}",
   "version": "0.0.0",
   "description": "{{ cookiecutter.description }}",
   "license": "UNLICENSED",
diff --git a/plugins/scaffolder-backend/scripts/Dockerfile b/plugins/scaffolder-backend/scripts/Dockerfile
new file mode 100644
index 0000000000..b33c7cbe64
--- /dev/null
+++ b/plugins/scaffolder-backend/scripts/Dockerfile
@@ -0,0 +1,11 @@
+FROM alpine:3.7
+
+RUN apk add --update \
+	git \
+	python \
+	python-dev \
+	py-pip \
+	g++ && \
+	pip install cookiecutter && \
+	apk del g++ py-pip python-dev && \
+	rm -rf /var/cache/apk/* 
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
index ee5265fde8..cabb1d4f1e 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
@@ -16,9 +16,18 @@ import { TemplaterBase, TemplaterRunOptions } from '.';
  * limitations under the License.
  */
 import fs from 'fs-extra';
+import Docker from 'dockerode';
 
 export class CookieCutter implements TemplaterBase {
+  private docker:Docker;
+  constructor() {
+    this.docker = new Docker();
+  }
+
   public async run(options: TemplaterRunOptions): Promise<string> {
+    
+      
+    
     // first we need to make cookiecutter.json in the directory provided with the input values.
     const cookieInfo = {
       _copy_without_render: ['.github/workflows/*'],
@@ -26,7 +35,14 @@ export class CookieCutter implements TemplaterBase {
     };
 
     await fs.writeJSON(`${options.directory}/cookiecutter.json`, cookieInfo);
-    return '';
-    // run cookie cutter with new json
+    const realTemplatePath = await fs.promises.realpath(options.directory);
+    const outDir = realTemplatePath + '/result';
+
+
+    await this.docker.run('backstage/cookiecutter', ['cookiecutter', '--no-input', '-o', '/result', '/template', '--verbose'], process.stdout, {Volumes: { '/result': {}, '/template': {}}, HostConfig: {
+      Binds: [`${outDir}:/result`, `${realTemplatePath}:/template`],
+    }});
+    
+    return outDir;
   }
 }
diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index c9b92494fd..e71593b6ba 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -64,12 +64,15 @@ export async function createRouter(
     const preparer = preparers.get(mockEntity);
 
     // Run the preparer for the mock entity to produce a temporary directory with template in
-    const path = await preparer.prepare(mockEntity);
+    const skeletonPath = await preparer.prepare(mockEntity);
 
     // Run the templater on the mock directory with values from the post body
-    await templater.run({ directory: path, values: { component_id: 'test' } });
+    const templatedPath = await templater.run({
+      directory: skeletonPath,
+      values: { component_id: 'test', description: "Something for now" },
+    });
 
-    console.warn(path);
+    console.warn(templatedPath);
   });
 
   const app = express();
diff --git a/yarn.lock b/yarn.lock
index fd351efe36..88a9861af6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3520,6 +3520,13 @@
   resolved "https://registry.npmjs.org/@types/diff/-/diff-4.0.2.tgz#2e9bb89f9acc3ab0108f0f3dc4dbdcf2fff8a99c"
   integrity sha512-mIenTfsIe586/yzsyfql69KRnA75S8SVXQbTLpDejRrjH0QSJcpu3AUOi/Vjnt9IOsXKxPhJfGpQUNMueIU1fQ==
 
+"@types/dockerode@^2.5.32":
+  version "2.5.32"
+  resolved "https://registry.npmjs.org/@types/dockerode/-/dockerode-2.5.32.tgz#52d3628f605f8ea65202541c59a8a6dd166384fd"
+  integrity sha512-TfaGOoOHxsjkWRj2sPoQ3FLmTC5mVMhZ4kzZy13U7mjtIDoloE4e7AMj5jPLbffWB6Csy5DF5e0lC9M+tnKz/A==
+  dependencies:
+    "@types/node" "*"
+
 "@types/eslint-visitor-keys@^1.0.0":
   version "1.0.0"
   resolved "https://registry.npmjs.org/@types/eslint-visitor-keys/-/eslint-visitor-keys-1.0.0.tgz#1ee30d79544ca84d68d4b3cdb0af4f205663dd2d"

From 12db9bc694dba19bf992e91632f8283ac1738ca3 Mon Sep 17 00:00:00 2001
From: Ivan Shmidt <bahoc47@gmail.com>
Date: Tue, 23 Jun 2020 14:17:28 +0200
Subject: [PATCH 2/6] chore: add tests, merge cookiecutter.json

Co-authored-by: Ben Lambert <ben@blam.sh>
---
 plugins/scaffolder-backend/package.json       |   1 +
 .../react-ssr-template/cookiecutter.json      |   3 +
 .../scaffolder/templater/cookiecutter.test.ts | 119 ++++++++++++++++++
 .../src/scaffolder/templater/cookiecutter.ts  |  42 +++++--
 4 files changed, 154 insertions(+), 11 deletions(-)
 create mode 100644 plugins/scaffolder-backend/sample-templates/react-ssr-template/cookiecutter.json
 create mode 100644 plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts

diff --git a/plugins/scaffolder-backend/package.json b/plugins/scaffolder-backend/package.json
index e85a65e744..b356f026e5 100644
--- a/plugins/scaffolder-backend/package.json
+++ b/plugins/scaffolder-backend/package.json
@@ -23,6 +23,7 @@
   "dependencies": {
     "@backstage/backend-common": "^0.1.1-alpha.9",
     "@backstage/catalog-model": "^0.1.1-alpha.9",
+    "@backstage/config": "^0.1.1-alpha.9",
     "@types/express": "^4.17.6",
     "compression": "^1.7.4",
     "cors": "^2.8.5",
diff --git a/plugins/scaffolder-backend/sample-templates/react-ssr-template/cookiecutter.json b/plugins/scaffolder-backend/sample-templates/react-ssr-template/cookiecutter.json
new file mode 100644
index 0000000000..bc6e4b5347
--- /dev/null
+++ b/plugins/scaffolder-backend/sample-templates/react-ssr-template/cookiecutter.json
@@ -0,0 +1,3 @@
+{
+  "_copy_without_render": [".github/workflows/*"]
+}
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
new file mode 100644
index 0000000000..8362a759bf
--- /dev/null
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
@@ -0,0 +1,119 @@
+/*
+ * 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 { CookieCutter } from './cookiecutter';
+import fs from 'fs-extra';
+import os from 'os';
+
+const mockDocker = { run: jest.fn() };
+jest.mock(
+  'dockerode',
+  () =>
+    class {
+      constructor() {
+        return mockDocker;
+      }
+    },
+);
+
+describe('CookieCutter Templater', () => {
+  const cookie = new CookieCutter();
+
+  beforeEach(() => {
+    jest.resetAllMocks();
+  });
+
+  it('should write a cookiecutter.json file with the values from the entitiy', async () => {
+    const tempdir = os.tmpdir();
+
+    const values = {
+      component_id: 'test',
+      description: 'description',
+    };
+
+    await cookie.run({ directory: tempdir, values });
+
+    const cookieCutterJson = await fs.readJSON(`${tempdir}/cookiecutter.json`);
+
+    expect(cookieCutterJson).toEqual(expect.objectContaining(values));
+  });
+
+  it('should merge any value that is in the cookiecutter.json path already', async () => {
+    const tempdir = os.tmpdir();
+    const existingJson = {
+      _copy_without_render: ['./github/workflows/*'],
+    };
+    await fs.writeJSON(`${tempdir}/cookiecutter.json`, existingJson);
+
+    const values = {
+      component_id: 'hello',
+      description: 'im something cool',
+    };
+
+    await cookie.run({ directory: tempdir, values });
+
+    const cookieCutterJson = await fs.readJSON(`${tempdir}/cookiecutter.json`);
+
+    expect(cookieCutterJson).toEqual({ ...existingJson, ...values });
+  });
+
+  it('should run the correct docker container with the correct bindings for the volumes', async () => {
+    const tempdir = os.tmpdir();
+
+    const values = {
+      component_id: 'test',
+      description: 'description',
+    };
+
+    await cookie.run({ directory: tempdir, values });
+
+    const realpath = await fs.realpath(tempdir);
+
+    // TODO(blam): This might change when we publish our own cookiecutter image
+    // to @backstage/cookiecutter in docker hub.
+    expect(mockDocker.run).toHaveBeenCalledWith(
+      'backstage/cookiecutter',
+      ['cookiecutter', '--no-input', '-o', '/result', '/template', '--verbose'],
+      process.stdout,
+      expect.objectContaining({
+        HostConfig: {
+          Binds: expect.arrayContaining([
+            `${realpath}:/template`,
+            `${realpath}/result:/result`,
+          ]),
+        },
+        Volumes: {
+          '/template': {},
+          '/result': {},
+        },
+      }),
+    );
+  });
+
+  it('should return the result path to the end templated folder', async () => {
+    const tempdir = os.tmpdir();
+
+    const values = {
+      component_id: 'test',
+      description: 'description',
+    };
+
+    const path = await cookie.run({ directory: tempdir, values });
+
+    const realpath = await fs.realpath(tempdir);
+
+    expect(path).toBe(`${realpath}/result`);
+  });
+});
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
index cabb1d4f1e..e927108dc4 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
@@ -17,32 +17,52 @@ import { TemplaterBase, TemplaterRunOptions } from '.';
  */
 import fs from 'fs-extra';
 import Docker from 'dockerode';
+import { JsonValue } from '@backstage/config';
 
 export class CookieCutter implements TemplaterBase {
-  private docker:Docker;
+  private docker: Docker;
   constructor() {
     this.docker = new Docker();
   }
 
+  private async fetchTemplateCookieCutter(
+    directory: string,
+  ): Promise<Record<string, JsonValue>> {
+    try {
+      return await fs.readJSON(`${directory}/cookiecutter.json`);
+    } catch (ex) {
+      return {};
+    }
+  }
+
   public async run(options: TemplaterRunOptions): Promise<string> {
-    
-      
-    
-    // first we need to make cookiecutter.json in the directory provided with the input values.
+    // First lets grab the default cookiecutter.json file
+    const cookieCutterJson = await this.fetchTemplateCookieCutter(
+      options.directory,
+    );
+
     const cookieInfo = {
-      _copy_without_render: ['.github/workflows/*'],
+      ...cookieCutterJson,
       ...options.values,
     };
 
     await fs.writeJSON(`${options.directory}/cookiecutter.json`, cookieInfo);
+
     const realTemplatePath = await fs.promises.realpath(options.directory);
-    const outDir = realTemplatePath + '/result';
+    const outDir = `${realTemplatePath}/result`;
 
+    await this.docker.run(
+      'backstage/cookiecutter',
+      ['cookiecutter', '--no-input', '-o', '/result', '/template', '--verbose'],
+      process.stdout,
+      {
+        Volumes: { '/result': {}, '/template': {} },
+        HostConfig: {
+          Binds: [`${outDir}:/result`, `${realTemplatePath}:/template`],
+        },
+      },
+    );
 
-    await this.docker.run('backstage/cookiecutter', ['cookiecutter', '--no-input', '-o', '/result', '/template', '--verbose'], process.stdout, {Volumes: { '/result': {}, '/template': {}}, HostConfig: {
-      Binds: [`${outDir}:/result`, `${realTemplatePath}:/template`],
-    }});
-    
     return outDir;
   }
 }

From e59cac61fd44d153c6940963b85ac50c3a3021e6 Mon Sep 17 00:00:00 2001
From: Ivan Shmidt <bahoc47@gmail.com>
Date: Tue, 23 Jun 2020 15:30:38 +0200
Subject: [PATCH 3/6] feat(scaffolder): error handling, log propagation

Co-authored-by: Ben Lambert <ben@blam.sh>
---
 .../scaffolder/templater/cookiecutter.test.ts | 70 +++++++++++++++++--
 .../src/scaffolder/templater/cookiecutter.ts  | 22 ++++--
 .../src/scaffolder/templater/index.ts         |  3 +
 .../scaffolder-backend/src/service/router.ts  |  2 +-
 4 files changed, 88 insertions(+), 9 deletions(-)

diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
index 8362a759bf..bddf5a7b25 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
@@ -16,8 +16,11 @@
 import { CookieCutter } from './cookiecutter';
 import fs from 'fs-extra';
 import os from 'os';
+import Stream, { PassThrough } from 'stream';
 
-const mockDocker = { run: jest.fn() };
+const mockDocker = {
+  run: jest.fn<any, any>(() => [{ Error: null, StatusCode: 0 }]),
+};
 jest.mock(
   'dockerode',
   () =>
@@ -32,7 +35,7 @@ describe('CookieCutter Templater', () => {
   const cookie = new CookieCutter();
 
   beforeEach(() => {
-    jest.resetAllMocks();
+    jest.clearAllMocks();
   });
 
   it('should write a cookiecutter.json file with the values from the entitiy', async () => {
@@ -85,8 +88,8 @@ describe('CookieCutter Templater', () => {
     // to @backstage/cookiecutter in docker hub.
     expect(mockDocker.run).toHaveBeenCalledWith(
       'backstage/cookiecutter',
-      ['cookiecutter', '--no-input', '-o', '/result', '/template', '--verbose'],
-      process.stdout,
+      ['cookiecutter', '--no-input', '-o', '/result', '/template'],
+      expect.any(Stream),
       expect.objectContaining({
         HostConfig: {
           Binds: expect.arrayContaining([
@@ -116,4 +119,63 @@ describe('CookieCutter Templater', () => {
 
     expect(path).toBe(`${realpath}/result`);
   });
+
+  it('throws a correct error if the templating fails in docker', async () => {
+    mockDocker.run.mockResolvedValueOnce([
+      {
+        Error: new Error('Something went wrong with docker'),
+        StatusCode: 0,
+      },
+    ]);
+
+    const tempdir = os.tmpdir();
+
+    const values = {
+      component_id: 'test',
+      description: 'description',
+    };
+
+    await expect(cookie.run({ directory: tempdir, values })).rejects.toThrow(
+      /Something went wrong with docker/,
+    );
+  });
+
+  it('uses the passed stream as a log stream', async () => {
+    const logStream = new PassThrough();
+    const tempdir = os.tmpdir();
+
+    const values = {
+      component_id: 'test',
+      description: 'description',
+    };
+
+    await cookie.run({ directory: tempdir, values, logStream });
+
+    expect(mockDocker.run).toHaveBeenCalledWith(
+      expect.any(String),
+      expect.any(Array),
+      logStream,
+      expect.any(Object),
+    );
+  });
+
+  it('throws a correct error if the container returns a non-zero exit code', async () => {
+    mockDocker.run.mockResolvedValueOnce([
+      {
+        Error: null,
+        StatusCode: 1,
+      },
+    ]);
+
+    const tempdir = os.tmpdir();
+
+    const values = {
+      component_id: 'test',
+      description: 'description',
+    };
+
+    await expect(cookie.run({ directory: tempdir, values })).rejects.toThrow(
+      /Docker container returned a non-zero exit code \(1\)/,
+    );
+  });
 });
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
index e927108dc4..b612900123 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
@@ -18,7 +18,7 @@ import { TemplaterBase, TemplaterRunOptions } from '.';
 import fs from 'fs-extra';
 import Docker from 'dockerode';
 import { JsonValue } from '@backstage/config';
-
+import { PassThrough } from 'stream';
 export class CookieCutter implements TemplaterBase {
   private docker: Docker;
   constructor() {
@@ -51,10 +51,12 @@ export class CookieCutter implements TemplaterBase {
     const realTemplatePath = await fs.promises.realpath(options.directory);
     const outDir = `${realTemplatePath}/result`;
 
-    await this.docker.run(
+    const [
+      { Error: dockerError, StatusCode: containerStatusCode },
+    ] = await this.docker.run(
       'backstage/cookiecutter',
-      ['cookiecutter', '--no-input', '-o', '/result', '/template', '--verbose'],
-      process.stdout,
+      ['cookiecutter', '--no-input', '-o', '/result', '/template'],
+      options.logStream ?? new PassThrough(),
       {
         Volumes: { '/result': {}, '/template': {} },
         HostConfig: {
@@ -63,6 +65,18 @@ export class CookieCutter implements TemplaterBase {
       },
     );
 
+    if (dockerError) {
+      throw new Error(
+        `Docker failed to run with the following error message: ${dockerError}`,
+      );
+    }
+
+    if (containerStatusCode !== 0) {
+      throw new Error(
+        `Docker container returned a non-zero exit code (${containerStatusCode})`,
+      );
+    }
+
     return outDir;
   }
 }
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/index.ts b/plugins/scaffolder-backend/src/scaffolder/templater/index.ts
index 80570a1c48..0c255354fe 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/index.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/index.ts
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+import type { Writable } from 'stream';
+
 export interface RequiredTemplateValues {
   component_id: string;
 }
@@ -21,6 +23,7 @@ export interface RequiredTemplateValues {
 export interface TemplaterRunOptions {
   directory: string;
   values: RequiredTemplateValues & object;
+  logStream?: Writable;
 }
 
 export abstract class TemplaterBase {
diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index e71593b6ba..6636fc4b68 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -69,7 +69,7 @@ export async function createRouter(
     // Run the templater on the mock directory with values from the post body
     const templatedPath = await templater.run({
       directory: skeletonPath,
-      values: { component_id: 'test', description: "Something for now" },
+      values: { component_id: 'test' },
     });
 
     console.warn(templatedPath);

From 0fe8e594f238702447f99c8d9654dd712cd33fbc Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Tue, 23 Jun 2020 18:07:03 +0200
Subject: [PATCH 4/6] refactor(scaffolder): Moving out the dockerish logic into
 something that is easy to consume for other templaters

---
 .../react-ssr-template/template.yaml          |   1 -
 .../scaffolder/templater/cookiecutter.test.ts | 115 ++++-----------
 .../src/scaffolder/templater/cookiecutter.ts  |  48 ++-----
 .../src/scaffolder/templater/helpers.test.ts  | 131 ++++++++++++++++++
 .../src/scaffolder/templater/helpers.ts       |  75 ++++++++++
 .../src/scaffolder/templater/templaters.ts    |  38 +++++
 6 files changed, 286 insertions(+), 122 deletions(-)
 create mode 100644 plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts
 create mode 100644 plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts
 create mode 100644 plugins/scaffolder-backend/src/scaffolder/templater/templaters.ts

diff --git a/plugins/scaffolder-backend/sample-templates/react-ssr-template/template.yaml b/plugins/scaffolder-backend/sample-templates/react-ssr-template/template.yaml
index 17f9ebbf7d..6834f0d1b6 100644
--- a/plugins/scaffolder-backend/sample-templates/react-ssr-template/template.yaml
+++ b/plugins/scaffolder-backend/sample-templates/react-ssr-template/template.yaml
@@ -7,4 +7,3 @@ metadata:
 spec:
   type: cookiecutter
   path: '.'
-
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
index bddf5a7b25..bba3705a41 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
@@ -13,27 +13,23 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+jest.mock('./helpers', () => ({ runDockerContainer: jest.fn() }));
+
 import { CookieCutter } from './cookiecutter';
 import fs from 'fs-extra';
 import os from 'os';
-import Stream, { PassThrough } from 'stream';
-
-const mockDocker = {
-  run: jest.fn<any, any>(() => [{ Error: null, StatusCode: 0 }]),
-};
-jest.mock(
-  'dockerode',
-  () =>
-    class {
-      constructor() {
-        return mockDocker;
-      }
-    },
-);
+import { RunDockerContainerOptions } from './helpers';
+import { PassThrough } from 'stream';
 
 describe('CookieCutter Templater', () => {
   const cookie = new CookieCutter();
 
+  const {
+    runDockerContainer,
+  }: {
+    runDockerContainer: jest.Mock<RunDockerContainerOptions>;
+  } = require('./helpers');
+
   beforeEach(() => {
     jest.clearAllMocks();
   });
@@ -82,29 +78,14 @@ describe('CookieCutter Templater', () => {
 
     await cookie.run({ directory: tempdir, values });
 
-    const realpath = await fs.realpath(tempdir);
-
-    // TODO(blam): This might change when we publish our own cookiecutter image
-    // to @backstage/cookiecutter in docker hub.
-    expect(mockDocker.run).toHaveBeenCalledWith(
-      'backstage/cookiecutter',
-      ['cookiecutter', '--no-input', '-o', '/result', '/template'],
-      expect.any(Stream),
-      expect.objectContaining({
-        HostConfig: {
-          Binds: expect.arrayContaining([
-            `${realpath}:/template`,
-            `${realpath}/result:/result`,
-          ]),
-        },
-        Volumes: {
-          '/template': {},
-          '/result': {},
-        },
-      }),
-    );
+    expect(runDockerContainer).toHaveBeenCalledWith({
+      imageName: 'backstage/cookiecutter',
+      args: ['cookiecutter', '--no-input', '-o', '/result', '/template'],
+      templateDir: tempdir,
+      resultDir: `${tempdir}/result`,
+      logStream: undefined,
+    });
   });
-
   it('should return the result path to the end templated folder', async () => {
     const tempdir = os.tmpdir();
 
@@ -115,18 +96,11 @@ describe('CookieCutter Templater', () => {
 
     const path = await cookie.run({ directory: tempdir, values });
 
-    const realpath = await fs.realpath(tempdir);
-
-    expect(path).toBe(`${realpath}/result`);
+    expect(path).toBe(`${tempdir}/result`);
   });
 
-  it('throws a correct error if the templating fails in docker', async () => {
-    mockDocker.run.mockResolvedValueOnce([
-      {
-        Error: new Error('Something went wrong with docker'),
-        StatusCode: 0,
-      },
-    ]);
+  it('should pass through the streamer to the run docker helper', async () => {
+    const stream = new PassThrough();
 
     const tempdir = os.tmpdir();
 
@@ -135,47 +109,14 @@ describe('CookieCutter Templater', () => {
       description: 'description',
     };
 
-    await expect(cookie.run({ directory: tempdir, values })).rejects.toThrow(
-      /Something went wrong with docker/,
-    );
-  });
+    await cookie.run({ directory: tempdir, values, logStream: stream });
 
-  it('uses the passed stream as a log stream', async () => {
-    const logStream = new PassThrough();
-    const tempdir = os.tmpdir();
-
-    const values = {
-      component_id: 'test',
-      description: 'description',
-    };
-
-    await cookie.run({ directory: tempdir, values, logStream });
-
-    expect(mockDocker.run).toHaveBeenCalledWith(
-      expect.any(String),
-      expect.any(Array),
-      logStream,
-      expect.any(Object),
-    );
-  });
-
-  it('throws a correct error if the container returns a non-zero exit code', async () => {
-    mockDocker.run.mockResolvedValueOnce([
-      {
-        Error: null,
-        StatusCode: 1,
-      },
-    ]);
-
-    const tempdir = os.tmpdir();
-
-    const values = {
-      component_id: 'test',
-      description: 'description',
-    };
-
-    await expect(cookie.run({ directory: tempdir, values })).rejects.toThrow(
-      /Docker container returned a non-zero exit code \(1\)/,
-    );
+    expect(runDockerContainer).toHaveBeenCalledWith({
+      imageName: 'backstage/cookiecutter',
+      args: ['cookiecutter', '--no-input', '-o', '/result', '/template'],
+      templateDir: tempdir,
+      resultDir: `${tempdir}/result`,
+      logStream: stream,
+    });
   });
 });
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
index b612900123..70a0cc28af 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
@@ -16,15 +16,10 @@ import { TemplaterBase, TemplaterRunOptions } from '.';
  * limitations under the License.
  */
 import fs from 'fs-extra';
-import Docker from 'dockerode';
 import { JsonValue } from '@backstage/config';
-import { PassThrough } from 'stream';
-export class CookieCutter implements TemplaterBase {
-  private docker: Docker;
-  constructor() {
-    this.docker = new Docker();
-  }
+import { runDockerContainer } from './helpers';
 
+export class CookieCutter implements TemplaterBase {
   private async fetchTemplateCookieCutter(
     directory: string,
   ): Promise<Record<string, JsonValue>> {
@@ -48,35 +43,20 @@ export class CookieCutter implements TemplaterBase {
 
     await fs.writeJSON(`${options.directory}/cookiecutter.json`, cookieInfo);
 
-    const realTemplatePath = await fs.promises.realpath(options.directory);
-    const outDir = `${realTemplatePath}/result`;
+    const templateDir = options.directory;
 
-    const [
-      { Error: dockerError, StatusCode: containerStatusCode },
-    ] = await this.docker.run(
-      'backstage/cookiecutter',
-      ['cookiecutter', '--no-input', '-o', '/result', '/template'],
-      options.logStream ?? new PassThrough(),
-      {
-        Volumes: { '/result': {}, '/template': {} },
-        HostConfig: {
-          Binds: [`${outDir}:/result`, `${realTemplatePath}:/template`],
-        },
-      },
-    );
+    // TODO(blam): This should be an entirely different directory on the host machine
+    // not in the template directory
+    const resultDir = `${templateDir}/result`;
 
-    if (dockerError) {
-      throw new Error(
-        `Docker failed to run with the following error message: ${dockerError}`,
-      );
-    }
+    await runDockerContainer({
+      imageName: 'backstage/cookiecutter',
+      args: ['cookiecutter', '--no-input', '-o', '/result', '/template'],
+      templateDir,
+      resultDir,
+      logStream: options.logStream,
+    });
 
-    if (containerStatusCode !== 0) {
-      throw new Error(
-        `Docker container returned a non-zero exit code (${containerStatusCode})`,
-      );
-    }
-
-    return outDir;
+    return resultDir;
   }
 }
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts
new file mode 100644
index 0000000000..a5ac00165e
--- /dev/null
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts
@@ -0,0 +1,131 @@
+/*
+ * 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 Stream, { PassThrough } from 'stream';
+import os from 'os';
+import fs from 'fs';
+
+const mockDocker = {
+  run: jest.fn<any, any>(() => [{ Error: null, StatusCode: 0 }]),
+};
+
+jest.mock(
+  'dockerode',
+  () =>
+    class {
+      constructor() {
+        return mockDocker;
+      }
+    },
+);
+
+import { runDockerContainer } from './helpers';
+
+describe('helpers', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe('runDockerContainer', () => {
+    const imageName = 'blam/github:ben';
+    const args = ['bash', '-c', 'echo lol'];
+    const templateDir = os.tmpdir();
+    const resultDir = os.tmpdir();
+
+    it('should call the dockerClient run command with the correct arguments passed through', async () => {
+      await runDockerContainer({
+        imageName,
+        args,
+        templateDir,
+        resultDir,
+      });
+
+      expect(mockDocker.run).toHaveBeenCalledWith(
+        imageName,
+        args,
+        expect.any(Stream),
+        expect.objectContaining({
+          HostConfig: {
+            Binds: expect.arrayContaining([
+              `${await fs.promises.realpath(templateDir)}:/template`,
+              `${await fs.promises.realpath(resultDir)}:/result`,
+            ]),
+          },
+          Volumes: {
+            '/template': {},
+            '/result': {},
+          },
+        }),
+      );
+    });
+
+    it('throws a correct error if the templating fails in docker', async () => {
+      mockDocker.run.mockResolvedValueOnce([
+        {
+          Error: new Error('Something went wrong with docker'),
+          StatusCode: 0,
+        },
+      ]);
+
+      await expect(
+        runDockerContainer({ imageName, args, templateDir, resultDir }),
+      ).rejects.toThrow(/Something went wrong with docker/);
+    });
+
+    it('throws a correct error when the response code of the container is non-zero', async () => {
+      mockDocker.run.mockResolvedValueOnce([
+        {
+          Error: null,
+          StatusCode: 123,
+        },
+      ]);
+
+      await expect(
+        runDockerContainer({ imageName, args, templateDir, resultDir }),
+      ).rejects.toThrow(
+        /Docker container returned a non-zero exit code \(123\)/,
+      );
+    });
+
+    it('should pass through the log stream to the docker client', async () => {
+      const logStream = new PassThrough();
+      await runDockerContainer({
+        imageName,
+        args,
+        templateDir,
+        resultDir,
+        logStream,
+      });
+
+      expect(mockDocker.run).toHaveBeenCalledWith(
+        imageName,
+        args,
+        logStream,
+        expect.objectContaining({
+          HostConfig: {
+            Binds: expect.arrayContaining([
+              `${await fs.promises.realpath(templateDir)}:/template`,
+              `${await fs.promises.realpath(resultDir)}:/result`,
+            ]),
+          },
+          Volumes: {
+            '/template': {},
+            '/result': {},
+          },
+        }),
+      );
+    });
+  });
+});
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts
new file mode 100644
index 0000000000..f60dcfc664
--- /dev/null
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts
@@ -0,0 +1,75 @@
+/*
+ * 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 Docker from 'dockerode';
+import { Writable, PassThrough } from 'stream';
+import fs from 'fs';
+
+export type RunDockerContainerOptions = {
+  imageName: string;
+  args: string[];
+  logStream?: Writable;
+  resultDir: string;
+  templateDir: string;
+};
+
+const dockerClient = new Docker();
+/**
+ *
+ * @param options the options object
+ * @param options.imageName the image to run
+ * @param options.args the arguments to pass the container
+ * @param options.logStream the log streamer to capture log messages
+ * @param options.resultDir the /result path inside the container
+ * @param options.templateDir the /template path inside the container
+ */
+export const runDockerContainer = async ({
+  imageName,
+  args,
+  logStream = new PassThrough(),
+  resultDir,
+  templateDir,
+}: RunDockerContainerOptions) => {
+  const [{ Error: error, StatusCode: statusCode }] = await dockerClient.run(
+    imageName,
+    args,
+    logStream,
+    {
+      Volumes: { '/result': {}, '/template': {} },
+      HostConfig: {
+        Binds: [
+          // Need to use realpath here as Docker mounting does not like
+          // symlinks for binding volumes
+          `${await fs.promises.realpath(resultDir)}:/result`,
+          `${await fs.promises.realpath(templateDir)}:/template`,
+        ],
+      },
+    },
+  );
+
+  if (error) {
+    throw new Error(
+      `Docker failed to run with the following error message: ${error}`,
+    );
+  }
+
+  if (statusCode !== 0) {
+    throw new Error(
+      `Docker container returned a non-zero exit code (${statusCode})`,
+    );
+  }
+
+  return { error, statusCode };
+};
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/templaters.ts b/plugins/scaffolder-backend/src/scaffolder/templater/templaters.ts
new file mode 100644
index 0000000000..235a699a95
--- /dev/null
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/templaters.ts
@@ -0,0 +1,38 @@
+/*
+ * 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, RemoteProtocol, PreparerBuilder } from './types';
+import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
+import { parseLocationAnnotation } from './helpers';
+
+export class Templaters implements PreparerBuilder {
+  private templaterMap = new Map<RemoteProtocol, PreparerBase>();
+
+  register(protocol: RemoteProtocol, preparer: PreparerBase) {
+    this.templaterMap.set(protocol, preparer);
+  }
+
+  get(template: TemplateEntityV1alpha1): PreparerBase {
+    const { protocol } = parseLocationAnnotation(template);
+    const preparer = this.templaterMap.get(protocol);
+
+    if (!preparer) {
+      throw new Error(`No preparer registered for type: "${protocol}"`);
+    }
+
+    return preparer;
+  }
+}

From 7ead8675dd130af527830d6e71049c8bc58bc2f9 Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Wed, 24 Jun 2020 10:47:43 +0200
Subject: [PATCH 5/6] chore(scaffolder): code review comments, passing down the
 docker client

---
 packages/backend/package.json                 |  2 +
 packages/backend/src/plugins/scaffolder.ts    |  4 +-
 plugins/scaffolder-backend/src/index.ts       |  1 +
 .../scaffolder/templater/cookiecutter.test.ts | 43 ++++++++++++++++---
 .../src/scaffolder/templater/cookiecutter.ts  |  5 +++
 .../src/scaffolder/templater/helpers.test.ts  | 40 +++++++++--------
 .../src/scaffolder/templater/helpers.ts       |  6 ++-
 .../src/scaffolder/templater/index.ts         |  8 ++--
 .../scaffolder-backend/src/service/router.ts  |  5 ++-
 9 files changed, 82 insertions(+), 32 deletions(-)

diff --git a/packages/backend/package.json b/packages/backend/package.json
index a4d5f059f9..2ae211fd8e 100644
--- a/packages/backend/package.json
+++ b/packages/backend/package.json
@@ -26,6 +26,7 @@
     "@backstage/plugin-identity-backend": "^0.1.1-alpha.10",
     "@backstage/plugin-scaffolder-backend": "^0.1.1-alpha.10",
     "@backstage/plugin-sentry-backend": "^0.1.1-alpha.10",
+    "dockerode": "^3.2.0",
     "express": "^4.17.1",
     "knex": "^0.21.1",
     "sqlite3": "^4.2.0",
@@ -33,6 +34,7 @@
   },
   "devDependencies": {
     "@backstage/cli": "^0.1.1-alpha.10",
+    "@types/dockerode": "^2.5.32",
     "@types/express": "^4.17.6",
     "@types/express-serve-static-core": "^4.17.5",
     "@types/helmet": "^0.0.47"
diff --git a/packages/backend/src/plugins/scaffolder.ts b/packages/backend/src/plugins/scaffolder.ts
index 95d28eacb1..1b0ee46969 100644
--- a/packages/backend/src/plugins/scaffolder.ts
+++ b/packages/backend/src/plugins/scaffolder.ts
@@ -22,15 +22,17 @@ import {
   Preparers,
 } from '@backstage/plugin-scaffolder-backend';
 import type { PluginEnvironment } from '../types';
+import Docker from 'dockerode';
 
 export default async function createPlugin({ logger }: PluginEnvironment) {
   const templater = new CookieCutter();
   const filePreparer = new FilePreparer();
   const githubPreparer = new GithubPreparer();
   const preparers = new Preparers();
+  const dockerClient = new Docker();
 
   preparers.register('file', filePreparer);
   preparers.register('github', githubPreparer);
 
-  return await createRouter({ preparers, templater, logger });
+  return await createRouter({ preparers, templater, logger, dockerClient });
 }
diff --git a/plugins/scaffolder-backend/src/index.ts b/plugins/scaffolder-backend/src/index.ts
index c461bfede6..0a0a4cb95f 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';
+
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
index bba3705a41..7c78badff1 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.test.ts
@@ -20,18 +20,21 @@ import fs from 'fs-extra';
 import os from 'os';
 import { RunDockerContainerOptions } from './helpers';
 import { PassThrough } from 'stream';
+import Docker from 'dockerode';
 
 describe('CookieCutter Templater', () => {
   const cookie = new CookieCutter();
-
+  const mockDocker = {} as Docker;
   const {
     runDockerContainer,
   }: {
     runDockerContainer: jest.Mock<RunDockerContainerOptions>;
   } = require('./helpers');
 
-  beforeEach(() => {
+  beforeEach(async () => {
     jest.clearAllMocks();
+
+    await fs.remove(`${os.tmpdir()}/cookiecutter.json`);
   });
 
   it('should write a cookiecutter.json file with the values from the entitiy', async () => {
@@ -42,7 +45,7 @@ describe('CookieCutter Templater', () => {
       description: 'description',
     };
 
-    await cookie.run({ directory: tempdir, values });
+    await cookie.run({ directory: tempdir, values, dockerClient: mockDocker });
 
     const cookieCutterJson = await fs.readJSON(`${tempdir}/cookiecutter.json`);
 
@@ -61,13 +64,28 @@ describe('CookieCutter Templater', () => {
       description: 'im something cool',
     };
 
-    await cookie.run({ directory: tempdir, values });
+    await cookie.run({ directory: tempdir, values, dockerClient: mockDocker });
 
     const cookieCutterJson = await fs.readJSON(`${tempdir}/cookiecutter.json`);
 
     expect(cookieCutterJson).toEqual({ ...existingJson, ...values });
   });
 
+  it('should throw an error if the cookiecutter json is malformed and not missing', async () => {
+    const tempdir = os.tmpdir();
+
+    await fs.writeFile(`${tempdir}/cookiecutter.json`, "{'");
+
+    const values = {
+      component_id: 'hello',
+      description: 'im something cool',
+    };
+
+    await expect(
+      cookie.run({ directory: tempdir, values, dockerClient: mockDocker }),
+    ).rejects.toThrow(/Unexpected token ' in JSON at position 1/);
+  });
+
   it('should run the correct docker container with the correct bindings for the volumes', async () => {
     const tempdir = os.tmpdir();
 
@@ -76,7 +94,7 @@ describe('CookieCutter Templater', () => {
       description: 'description',
     };
 
-    await cookie.run({ directory: tempdir, values });
+    await cookie.run({ directory: tempdir, values, dockerClient: mockDocker });
 
     expect(runDockerContainer).toHaveBeenCalledWith({
       imageName: 'backstage/cookiecutter',
@@ -84,6 +102,7 @@ describe('CookieCutter Templater', () => {
       templateDir: tempdir,
       resultDir: `${tempdir}/result`,
       logStream: undefined,
+      dockerClient: mockDocker,
     });
   });
   it('should return the result path to the end templated folder', async () => {
@@ -94,7 +113,11 @@ describe('CookieCutter Templater', () => {
       description: 'description',
     };
 
-    const path = await cookie.run({ directory: tempdir, values });
+    const path = await cookie.run({
+      directory: tempdir,
+      values,
+      dockerClient: mockDocker,
+    });
 
     expect(path).toBe(`${tempdir}/result`);
   });
@@ -109,7 +132,12 @@ describe('CookieCutter Templater', () => {
       description: 'description',
     };
 
-    await cookie.run({ directory: tempdir, values, logStream: stream });
+    await cookie.run({
+      directory: tempdir,
+      values,
+      logStream: stream,
+      dockerClient: mockDocker,
+    });
 
     expect(runDockerContainer).toHaveBeenCalledWith({
       imageName: 'backstage/cookiecutter',
@@ -117,6 +145,7 @@ describe('CookieCutter Templater', () => {
       templateDir: tempdir,
       resultDir: `${tempdir}/result`,
       logStream: stream,
+      dockerClient: mockDocker,
     });
   });
 });
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
index 70a0cc28af..a95eee7fb4 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/cookiecutter.ts
@@ -26,6 +26,10 @@ export class CookieCutter implements TemplaterBase {
     try {
       return await fs.readJSON(`${directory}/cookiecutter.json`);
     } catch (ex) {
+      if (ex.code !== 'ENOENT') {
+        throw ex;
+      }
+
       return {};
     }
   }
@@ -55,6 +59,7 @@ export class CookieCutter implements TemplaterBase {
       templateDir,
       resultDir,
       logStream: options.logStream,
+      dockerClient: options.dockerClient,
     });
 
     return resultDir;
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts
index a5ac00165e..d27eb4f93f 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.test.ts
@@ -16,26 +16,16 @@
 import Stream, { PassThrough } from 'stream';
 import os from 'os';
 import fs from 'fs';
-
-const mockDocker = {
-  run: jest.fn<any, any>(() => [{ Error: null, StatusCode: 0 }]),
-};
-
-jest.mock(
-  'dockerode',
-  () =>
-    class {
-      constructor() {
-        return mockDocker;
-      }
-    },
-);
-
+import Docker from 'dockerode';
 import { runDockerContainer } from './helpers';
 
 describe('helpers', () => {
+  const mockDocker = new Docker() as jest.Mocked<Docker>;
+
   beforeEach(() => {
-    jest.clearAllMocks();
+    jest
+      .spyOn(mockDocker, 'run')
+      .mockResolvedValue([{ Error: null, StatusCode: 0 }]);
   });
 
   describe('runDockerContainer', () => {
@@ -50,6 +40,7 @@ describe('helpers', () => {
         args,
         templateDir,
         resultDir,
+        dockerClient: mockDocker,
       });
 
       expect(mockDocker.run).toHaveBeenCalledWith(
@@ -80,7 +71,13 @@ describe('helpers', () => {
       ]);
 
       await expect(
-        runDockerContainer({ imageName, args, templateDir, resultDir }),
+        runDockerContainer({
+          imageName,
+          args,
+          templateDir,
+          resultDir,
+          dockerClient: mockDocker,
+        }),
       ).rejects.toThrow(/Something went wrong with docker/);
     });
 
@@ -93,7 +90,13 @@ describe('helpers', () => {
       ]);
 
       await expect(
-        runDockerContainer({ imageName, args, templateDir, resultDir }),
+        runDockerContainer({
+          imageName,
+          args,
+          templateDir,
+          resultDir,
+          dockerClient: mockDocker,
+        }),
       ).rejects.toThrow(
         /Docker container returned a non-zero exit code \(123\)/,
       );
@@ -107,6 +110,7 @@ describe('helpers', () => {
         templateDir,
         resultDir,
         logStream,
+        dockerClient: mockDocker,
       });
 
       expect(mockDocker.run).toHaveBeenCalledWith(
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts
index f60dcfc664..2856a016e4 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/helpers.ts
@@ -13,8 +13,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import Docker from 'dockerode';
 import { Writable, PassThrough } from 'stream';
+import Docker from 'dockerode';
 import fs from 'fs';
 
 export type RunDockerContainerOptions = {
@@ -23,9 +23,9 @@ export type RunDockerContainerOptions = {
   logStream?: Writable;
   resultDir: string;
   templateDir: string;
+  dockerClient: Docker;
 };
 
-const dockerClient = new Docker();
 /**
  *
  * @param options the options object
@@ -34,6 +34,7 @@ const dockerClient = new Docker();
  * @param options.logStream the log streamer to capture log messages
  * @param options.resultDir the /result path inside the container
  * @param options.templateDir the /template path inside the container
+ * @param options.dockerClient the dockerClient to use
  */
 export const runDockerContainer = async ({
   imageName,
@@ -41,6 +42,7 @@ export const runDockerContainer = async ({
   logStream = new PassThrough(),
   resultDir,
   templateDir,
+  dockerClient,
 }: RunDockerContainerOptions) => {
   const [{ Error: error, StatusCode: statusCode }] = await dockerClient.run(
     imageName,
diff --git a/plugins/scaffolder-backend/src/scaffolder/templater/index.ts b/plugins/scaffolder-backend/src/scaffolder/templater/index.ts
index 0c255354fe..8885e65308 100644
--- a/plugins/scaffolder-backend/src/scaffolder/templater/index.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/templater/index.ts
@@ -15,6 +15,7 @@
  */
 
 import type { Writable } from 'stream';
+import Docker from 'dockerode';
 
 export interface RequiredTemplateValues {
   component_id: string;
@@ -24,12 +25,13 @@ export interface TemplaterRunOptions {
   directory: string;
   values: RequiredTemplateValues & object;
   logStream?: Writable;
+  dockerClient: Docker;
 }
 
-export abstract class TemplaterBase {
+export type TemplaterBase = {
   // runs the templating with the values and returns the directory to push the VCS
-  abstract async run(opts: TemplaterRunOptions): Promise<string>;
-}
+  run(opts: TemplaterRunOptions): Promise<string>;
+};
 
 export interface TemplaterConfig {
   templater?: TemplaterBase;
diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index 16b119da02..ab39864e76 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -19,18 +19,20 @@ import Router from 'express-promise-router';
 import express from 'express';
 import { PreparerBuilder, TemplaterBase } from '../scaffolder';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
+import Docker from 'dockerode';
 
 export interface RouterOptions {
   preparers: PreparerBuilder;
   templater: TemplaterBase;
   logger: Logger;
+  dockerClient: Docker;
 }
 
 export async function createRouter(
   options: RouterOptions,
 ): Promise<express.Router> {
   const router = Router();
-  const { preparers, templater, logger: parentLogger } = options;
+  const { preparers, templater, logger: parentLogger, dockerClient } = options;
   const logger = parentLogger.child({ plugin: 'scaffolder' });
 
   router.post('/v1/jobs', async (_, res) => {
@@ -72,6 +74,7 @@ export async function createRouter(
     const templatedPath = await templater.run({
       directory: skeletonPath,
       values: { component_id: 'test' },
+      dockerClient,
     });
 
     console.warn(templatedPath);

From d581284890a653c1fbb7247cecd4effefff224e6 Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Wed, 24 Jun 2020 14:01:13 +0200
Subject: [PATCH 6/6] chore(scaffolder): fixing the type deps

---
 plugins/scaffolder-backend/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/scaffolder-backend/package.json b/plugins/scaffolder-backend/package.json
index 061f6ca814..c8c40d7b67 100644
--- a/plugins/scaffolder-backend/package.json
+++ b/plugins/scaffolder-backend/package.json
@@ -25,6 +25,7 @@
     "@backstage/catalog-model": "^0.1.1-alpha.12",
     "@backstage/config": "^0.1.1-alpha.12",
     "@types/express": "^4.17.6",
+    "@types/dockerode": "^2.5.32",
     "compression": "^1.7.4",
     "cors": "^2.8.5",
     "dockerode": "^3.2.0",
@@ -40,7 +41,6 @@
   },
   "devDependencies": {
     "@backstage/cli": "^0.1.1-alpha.12",
-    "@types/dockerode": "^2.5.32",
     "@types/fs-extra": "^9.0.1",
     "@types/git-url-parse": "^9.0.0",
     "@types/nodegit": "0.26.5",