Add automatic discovery of CLI modules from project dependencies

The CLI now scans the project root's dependencies and devDependencies
for packages with the cli-module role, loading them automatically.
Falls back to the built-in set with a deprecation warning when no
modules are found. Updated create-app templates and the monorepo root
to include all CLI modules as explicit devDependencies.

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

packages/cli/src/index.ts

@@ -14,20 +14,44 @@
  * limitations under the License.
  */
 
+import chalk from 'chalk';
 import { CliInitializer } from './wiring/CliInitializer';
+import { discoverCliModules } from './wiring/discoverCliModules';
 
 (async () => {
   const initializer = new CliInitializer();
-  initializer.add(import('@backstage/cli-module-build'));
-  initializer.add(import('@backstage/cli-module-config'));
-  initializer.add(import('@backstage/cli-module-create-github-app'));
-  initializer.add(import('@backstage/cli-module-info'));
-  initializer.add(import('@backstage/cli-module-lint'));
-  initializer.add(import('@backstage/cli-module-maintenance'));
-  initializer.add(import('@backstage/cli-module-migrate'));
-  initializer.add(import('@backstage/cli-module-new'));
-  initializer.add(import('@backstage/cli-module-test-jest'));
-  initializer.add(import('@backstage/cli-module-translations'));
-  initializer.add(import('@backstage/cli-module-auth'));
+
+  const discoveredModules = discoverCliModules();
+
+  if (discoveredModules.length > 0) {
+    for (const moduleName of discoveredModules) {
+      initializer.add(import(moduleName));
+    }
+  } else {
+    // No CLI modules found in the project root; fall back to the built-in
+    // set while printing a deprecation warning.
+    console.error(
+      chalk.yellow(
+        `No CLI modules found in the project root dependencies. ` +
+          `Falling back to the built-in set of modules.\n` +
+          `This fallback will be removed in a future release. ` +
+          `Please add the CLI modules you need as devDependencies ` +
+          `in your root package.json.\n`,
+      ),
+    );
+
+    initializer.add(import('@backstage/cli-module-build'));
+    initializer.add(import('@backstage/cli-module-config'));
+    initializer.add(import('@backstage/cli-module-create-github-app'));
+    initializer.add(import('@backstage/cli-module-info'));
+    initializer.add(import('@backstage/cli-module-lint'));
+    initializer.add(import('@backstage/cli-module-maintenance'));
+    initializer.add(import('@backstage/cli-module-migrate'));
+    initializer.add(import('@backstage/cli-module-new'));
+    initializer.add(import('@backstage/cli-module-test-jest'));
+    initializer.add(import('@backstage/cli-module-translations'));
+    initializer.add(import('@backstage/cli-module-auth'));
+  }
+
   await initializer.run();
 })();

packages/cli/src/wiring/discoverCliModules.ts

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2024 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 { targetPaths } from '@backstage/cli-common';
+import { PackageRoles } from '@backstage/cli-node';
+import fs from 'node:fs';
+import { resolve as resolvePath } from 'node:path';
+
+/**
+ * Scans the target project root's package.json for dependencies that are CLI
+ * modules (packages with `backstage.role === 'cli-module'`).
+ *
+ * Returns the names of discovered CLI module packages, or an empty array if
+ * none are found or the project root cannot be read.
+ */
+export function discoverCliModules(): string[] {
+  const rootDir = targetPaths.rootDir;
+  const pkgJsonPath = resolvePath(rootDir, 'package.json');
+
+  let projectPkg: {
+    dependencies?: Record<string, string>;
+    devDependencies?: Record<string, string>;
+  };
+  try {
+    projectPkg = JSON.parse(fs.readFileSync(pkgJsonPath, 'utf8'));
+  } catch {
+    return [];
+  }
+
+  const allDeps = {
+    ...projectPkg.dependencies,
+    ...projectPkg.devDependencies,
+  };
+
+  const modules: string[] = [];
+
+  for (const depName of Object.keys(allDeps)) {
+    try {
+      const depPkgPath = require.resolve(`${depName}/package.json`, {
+        paths: [rootDir],
+      });
+      const depPkg = JSON.parse(fs.readFileSync(depPkgPath, 'utf8'));
+      if (PackageRoles.getRoleFromPackage(depPkg) === 'cli-module') {
+        modules.push(depName);
+      }
+    } catch {
+      // Skip packages that can't be resolved or read
+    }
+  }
+
+  return modules;
+}