cli: added backend module templating factory

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/cyan-roses-relate.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Added the ability to create a plain backend module with the `new` command.

packages/cli/package.json

@@ -140,6 +140,8 @@
   },
   "devDependencies": {
     "@backstage/backend-common": "workspace:^",
+    "@backstage/backend-plugin-api": "workspace:^",
+    "@backstage/backend-test-utils": "workspace:^",
     "@backstage/config": "workspace:^",
     "@backstage/core-app-api": "workspace:^",
     "@backstage/core-components": "workspace:^",

packages/cli/src/lib/new/factories/backendModule.ts

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * 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 fs from 'fs-extra';
+import chalk from 'chalk';
+import camelCase from 'lodash/camelCase';
+import { paths } from '../../paths';
+import { addCodeownersEntry, getCodeownersFilePath } from '../../codeowners';
+import { createFactory, CreateContext } from '../types';
+import { addPackageDependency, Task } from '../../tasks';
+import {
+  moduleIdIdPrompt,
+  ownerPrompt,
+  pluginIdPrompt,
+} from './common/prompts';
+import { executePluginPackageTemplate } from './common/tasks';
+
+type Options = {
+  id: string;
+  moduleId: string;
+  owner?: string;
+  codeOwnersPath?: string;
+};
+
+export const backendModule = createFactory<Options>({
+  name: 'backend-module',
+  description: 'A new backend module',
+  optionsDiscovery: async () => ({
+    codeOwnersPath: await getCodeownersFilePath(paths.targetRoot),
+  }),
+  optionsPrompts: [pluginIdPrompt(), moduleIdIdPrompt(), ownerPrompt()],
+  async create(options: Options, ctx: CreateContext) {
+    const { id: pluginId, moduleId } = options;
+    const dirName = `${pluginId}-backend-module-${moduleId}`;
+    const name = ctx.scope
+      ? `@${ctx.scope}/plugin-${dirName}`
+      : `backstage-plugin-${dirName}`;
+
+    Task.log();
+    Task.log(`Creating backend module ${chalk.cyan(name)}`);
+
+    const targetDir = ctx.isMonoRepo
+      ? paths.resolveTargetRoot('plugins', dirName)
+      : paths.resolveTargetRoot(`backstage-plugin-${dirName}`);
+
+    const moduleCamelCase = camelCase(moduleId);
+    const modulePascalCase =
+      moduleCamelCase[0].toUpperCase() + moduleCamelCase.slice(1);
+    const moduleVar = `${camelCase(pluginId)}Module${modulePascalCase}`;
+    await executePluginPackageTemplate(ctx, {
+      targetDir,
+      templateName: 'default-backend-module',
+      values: {
+        pluginId,
+        moduleId,
+        name,
+        moduleVar,
+        packageVersion: ctx.defaultVersion,
+        privatePackage: ctx.private,
+        npmRegistry: ctx.npmRegistry,
+      },
+    });
+
+    if (await fs.pathExists(paths.resolveTargetRoot('packages/backend'))) {
+      await Task.forItem('backend', 'adding dependency', async () => {
+        await addPackageDependency(
+          paths.resolveTargetRoot('packages/backend/package.json'),
+          {
+            dependencies: {
+              [name]: `^${ctx.defaultVersion}`,
+            },
+          },
+        );
+      });
+    }
+
+    if (options.owner) {
+      await addCodeownersEntry(`/plugins/${dirName}`, options.owner);
+    }
+
+    await Task.forCommand('yarn install', { cwd: targetDir, optional: true });
+    await Task.forCommand('yarn lint --fix', {
+      cwd: targetDir,
+      optional: true,
+    });
+  },
+});

packages/cli/src/lib/new/factories/common/prompts.ts

@@ -33,6 +33,22 @@ export function pluginIdPrompt(): Prompt<{ id: string }> {
   };
 }
 
+export function moduleIdIdPrompt(): Prompt<{ moduleId: string }> {
+  return {
+    type: 'input',
+    name: 'moduleId',
+    message: 'Enter the ID of the module [required]',
+    validate: (value: string) => {
+      if (!value) {
+        return 'Please enter the ID of the module';
+      } else if (!/^[a-z0-9]+(-[a-z0-9]+)*$/.test(value)) {
+        return 'Module IDs must be lowercase and contain only letters, digits, and dashes.';
+      }
+      return true;
+    },
+  };
+}
+
 export function ownerPrompt(): Prompt<{
   owner?: string;
   codeOwnersPath?: string;

packages/cli/src/lib/new/factories/index.ts

@@ -16,6 +16,7 @@
 
 export { frontendPlugin } from './frontendPlugin';
 export { backendPlugin } from './backendPlugin';
+export { backendModule } from './backendModule';
 export { webLibraryPackage } from './webLibraryPackage';
 export { pluginCommon } from './pluginCommon';
 export { pluginNode } from './pluginNode';

packages/cli/src/lib/version.ts

@@ -35,6 +35,8 @@ leaving any imports in place.
 */
 
 import { version as backendCommon } from '../../../../packages/backend-common/package.json';
+import { version as backendPluginApi } from '../../../../packages/backend-plugin-api/package.json';
+import { version as backendTestUtils } from '../../../../packages/backend-test-utils/package.json';
 import { version as cli } from '../../../../packages/cli/package.json';
 import { version as config } from '../../../../packages/config/package.json';
 import { version as coreAppApi } from '../../../../packages/core-app-api/package.json';
@@ -47,6 +49,8 @@ import { version as scaffolderBackend } from '../../../../plugins/scaffolder-bac
 
 export const packageVersions: Record<string, string> = {
   '@backstage/backend-common': backendCommon,
+  '@backstage/backend-plugin-api': backendPluginApi,
+  '@backstage/backend-test-utils': backendTestUtils,
   '@backstage/cli': cli,
   '@backstage/config': config,
   '@backstage/core-app-api': coreAppApi,

packages/cli/templates/default-backend-module/.eslintrc.js

@@ -0,0 +1 @@
+module.exports = require('@backstage/cli/config/eslint-factory')(__dirname);

packages/cli/templates/default-backend-module/README.md.hbs

@@ -0,0 +1,5 @@
+# {{name}}
+
+The {{moduleId}} backend module for the {{pluginId}} plugin.
+
+_This plugin was created through the Backstage CLI_

packages/cli/templates/default-backend-module/package.json.hbs

@@ -0,0 +1,42 @@
+{
+  "name": "{{name}}",
+  "description": "The {{moduleId}} backend module for the {{pluginId}} plugin.",
+  "version": "{{packageVersion}}",
+  "main": "src/index.ts",
+  "types": "src/index.ts",
+  "license": "Apache-2.0",
+{{#if privatePackage}}
+  "private": {{privatePackage}},
+{{/if}}
+  "publishConfig": {
+{{#if npmRegistry}}
+    "registry": "{{npmRegistry}}",
+{{/if}}
+    "access": "public",
+    "main": "dist/index.cjs.js",
+    "types": "dist/index.d.ts"
+  },
+  "backstage": {
+    "role": "backend-plugin-module"
+  },
+  "scripts": {
+    "start": "backstage-cli package start",
+    "build": "backstage-cli package build",
+    "lint": "backstage-cli package lint",
+    "test": "backstage-cli package test",
+    "clean": "backstage-cli package clean",
+    "prepack": "backstage-cli package prepack",
+    "postpack": "backstage-cli package postpack"
+  },
+  "dependencies": {
+    "@backstage/backend-common": "{{versionQuery '@backstage/backend-common'}}",
+    "@backstage/backend-plugin-api": "{{versionQuery '@backstage/backend-plugin-api'}}"
+  },
+  "devDependencies": {
+    "@backstage/backend-test-utils": "{{versionQuery '@backstage/backend-test-utils'}}",
+    "@backstage/cli": "{{versionQuery '@backstage/cli'}}"
+  },
+  "files": [
+    "dist"
+  ]
+}

packages/cli/templates/default-backend-module/src/index.ts.hbs

@@ -0,0 +1,8 @@
+/***/
+/**
+ * The {{moduleId}} backend module for the {{pluginId}} plugin.
+ *
+ * @packageDocumentation
+ */
+
+export { {{moduleVar}} } from './module';

packages/cli/templates/default-backend-module/src/module.ts.hbs

@@ -0,0 +1,14 @@
+import { coreServices, createBackendModule } from '@backstage/backend-plugin-api';
+
+export const {{moduleVar}} = createBackendModule({
+  pluginId: '{{pluginId}}',
+  moduleId: '{{moduleId}}',
+  register(reg) {
+    reg.registerInit({
+      deps: { logger: coreServices.logger },
+      async init({ logger }) {
+        logger.info('Hello World!')
+      },
+    });
+  },
+});

packages/cli/templates/default-backend-module/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "@backstage/cli/config/tsconfig.json",
+  "include": ["src"],
+  "exclude": ["node_modules"],
+  "compilerOptions": {
+    "outDir": "dist-types",
+    "rootDir": "."
+  }
+}

yarn.lock

@@ -3578,6 +3578,8 @@ __metadata:
   resolution: "@backstage/cli@workspace:packages/cli"
   dependencies:
     "@backstage/backend-common": "workspace:^"
+    "@backstage/backend-plugin-api": "workspace:^"
+    "@backstage/backend-test-utils": "workspace:^"
     "@backstage/catalog-model": "workspace:^"
     "@backstage/cli-common": "workspace:^"
     "@backstage/cli-node": "workspace:^"