From 118e4861be8d791119614ea8acaa7fbc51aed366 Mon Sep 17 00:00:00 2001
From: Tim Jacomb <tim.jacomb@hmcts.net>
Date: Tue, 25 Aug 2020 11:27:56 +0100
Subject: [PATCH] Use cookie cutter installed on host

---
 plugins/scaffolder-backend/package.json       |  1 +
 .../stages/templater/cookiecutter.ts          | 43 ++++++++++++-------
 .../scaffolder/stages/templater/helpers.ts    | 43 +++++++++++++++++++
 yarn.lock                                     |  5 +++
 4 files changed, 76 insertions(+), 16 deletions(-)

diff --git a/plugins/scaffolder-backend/package.json b/plugins/scaffolder-backend/package.json
index 7112d0f49d..275da3700b 100644
--- a/plugins/scaffolder-backend/package.json
+++ b/plugins/scaffolder-backend/package.json
@@ -27,6 +27,7 @@
     "@octokit/rest": "^18.0.0",
     "@types/dockerode": "^2.5.32",
     "@types/express": "^4.17.6",
+    "command-exists-promise": "^2.0.2",
     "compression": "^1.7.4",
     "cors": "^2.8.5",
     "dockerode": "^3.2.0",
diff --git a/plugins/scaffolder-backend/src/scaffolder/stages/templater/cookiecutter.ts b/plugins/scaffolder-backend/src/scaffolder/stages/templater/cookiecutter.ts
index fff349cf82..21b6fc3dde 100644
--- a/plugins/scaffolder-backend/src/scaffolder/stages/templater/cookiecutter.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/stages/templater/cookiecutter.ts
@@ -15,11 +15,13 @@
  */
 import fs from 'fs-extra';
 import { JsonValue } from '@backstage/config';
-import { runDockerContainer } from './helpers';
+import { runDockerContainer, runCommand } from './helpers';
 import { TemplaterBase, TemplaterRunOptions } from '.';
 import path from 'path';
 import { TemplaterRunResult } from './types';
 
+const commandExists = require('command-exists-promise');
+
 export class CookieCutter implements TemplaterBase {
   private async fetchTemplateCookieCutter(
     directory: string,
@@ -51,21 +53,30 @@ export class CookieCutter implements TemplaterBase {
     const templateDir = options.directory;
     const resultDir = await fs.promises.mkdtemp(`${options.directory}-result`);
 
-    await runDockerContainer({
-      imageName: 'spotify/backstage-cookiecutter',
-      args: [
-        'cookiecutter',
-        '--no-input',
-        '-o',
-        '/result',
-        '/template',
-        '--verbose',
-      ],
-      templateDir,
-      resultDir,
-      logStream: options.logStream,
-      dockerClient: options.dockerClient,
-    });
+    const cookieCutterInstalled = await commandExists('cookiecutter');
+    if (cookieCutterInstalled) {
+      await runCommand({
+        command: 'cookiecutter',
+        args: ['--no-input', '-o', resultDir, templateDir, '--verbose'],
+        logStream: options.logStream,
+      });
+    } else {
+      await runDockerContainer({
+        imageName: 'spotify/backstage-cookiecutter',
+        args: [
+          'cookiecutter',
+          '--no-input',
+          '-o',
+          '/result',
+          '/template',
+          '--verbose',
+        ],
+        templateDir,
+        resultDir,
+        logStream: options.logStream,
+        dockerClient: options.dockerClient,
+      });
+    }
 
     return {
       resultDir: path.resolve(resultDir, options.values.component_id as string),
diff --git a/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts b/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts
index a3dea7ea5a..e71b63bfb0 100644
--- a/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/stages/templater/helpers.ts
@@ -18,6 +18,7 @@ import Docker from 'dockerode';
 import fs from 'fs';
 import { TemplateEntityV1alpha1 } from '@backstage/catalog-model';
 import { InputError } from '@backstage/backend-common';
+import { spawn } from 'child_process';
 
 export type RunDockerContainerOptions = {
   imageName: string;
@@ -29,6 +30,12 @@ export type RunDockerContainerOptions = {
   createOptions?: Docker.ContainerCreateOptions;
 };
 
+export type RunCommandOptions = {
+  command: string;
+  args: string[];
+  logStream?: Writable;
+};
+
 /**
  * Gets the templater key to use for templating from the entity
  * @param entity Template entity
@@ -43,6 +50,42 @@ export const getTemplaterKey = (entity: TemplateEntityV1alpha1): string => {
   return templater;
 };
 
+/**
+ *
+ * @param options the options object
+ * @param options.command the command to run
+ * @param options.args the arguments to pass the command
+ * @param options.logStream the log streamer to capture log messages
+ */
+export const runCommand = async ({
+  command,
+  args,
+  logStream = new PassThrough(),
+}: RunCommandOptions) => {
+  await new Promise((resolve, reject) => {
+    const process = spawn(command, args);
+
+    process.stdout.on('data', stream => {
+      logStream.write(stream);
+    });
+
+    process.stderr.on('data', stream => {
+      logStream.write(stream);
+    });
+
+    process.on('error', error => {
+      return reject(error);
+    });
+
+    process.on('close', code => {
+      if (code !== 0) {
+        return reject(`Command ${command} failed, exit code: ${code}`);
+      }
+      return resolve();
+    });
+  });
+};
+
 /**
  *
  * @param options the options object
diff --git a/yarn.lock b/yarn.lock
index 857b8b2cc0..6f725fe353 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -8104,6 +8104,11 @@ comma-separated-tokens@^1.0.0:
   resolved "https://registry.npmjs.org/comma-separated-tokens/-/comma-separated-tokens-1.0.8.tgz#632b80b6117867a158f1080ad498b2fbe7e3f5ea"
   integrity sha512-GHuDRO12Sypu2cV70d1dkA2EUmXHgntrzbpvOB+Qy+49ypNfGgFQIC2fhhXbnyrJRynDCAARsT7Ou0M6hirpfw==
 
+command-exists-promise@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.npmjs.org/command-exists-promise/-/command-exists-promise-2.0.2.tgz#7beecc4b218299f3c61fa69a4047aa0b36a64a99"
+  integrity sha512-T6PB6vdFrwnHXg/I0kivM3DqaCGZLjjYSOe0a5WgFKcz1sOnmOeIjnhQPXVXX3QjVbLyTJ85lJkX6lUpukTzaA==
+
 commander@^2.11.0, commander@^2.19.0, commander@^2.20.0, commander@^2.20.3, commander@^2.8.1, commander@~2.20.3:
   version "2.20.3"
   resolved "https://registry.npmjs.org/commander/-/commander-2.20.3.tgz#fd485e84c03eb4881c20722ba48035e8531aeb33"