cli: only load config schema that applies to the target package

.changeset/angry-bees-brush.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Only load config that applies to the target package for frontend build and serve tasks. Also added `--package <name>` flag to scope the config schema used by the `config:print` and `config:check` commands.

packages/cli/src/commands/app/build.ts

@@ -14,16 +14,22 @@
  * limitations under the License.
  */
 
+import fs from 'fs-extra';
 import { Command } from 'commander';
 import { buildBundle } from '../../lib/bundler';
 import { parseParallel, PARALLEL_ENV_VAR } from '../../lib/parallel';
 import { loadCliConfig } from '../../lib/config';
+import { paths } from '../../lib/paths';
 
 export default async (cmd: Command) => {
+  const { name } = await fs.readJson(paths.resolveTarget('package.json'));
   await buildBundle({
     entry: 'src/index',
     parallel: parseParallel(process.env[PARALLEL_ENV_VAR]),
     statsJsonEnabled: cmd.stats,
-    ...(await loadCliConfig(cmd.config)),
+    ...(await loadCliConfig({
+      args: cmd.config,
+      fromPackage: name,
+    })),
   });
 };

packages/cli/src/commands/app/serve.ts

@@ -14,15 +14,21 @@
  * limitations under the License.
  */
 
+import fs from 'fs-extra';
 import { Command } from 'commander';
 import { serveBundle } from '../../lib/bundler';
 import { loadCliConfig } from '../../lib/config';
+import { paths } from '../../lib/paths';
 
 export default async (cmd: Command) => {
+  const { name } = await fs.readJson(paths.resolveTarget('package.json'));
   const waitForExit = await serveBundle({
     entry: 'src/index',
     checksEnabled: cmd.check,
-    ...(await loadCliConfig(cmd.config)),
+    ...(await loadCliConfig({
+      args: cmd.config,
+      fromPackage: name,
+    })),
   });
 
   await waitForExit();

packages/cli/src/commands/config/print.ts

@@ -21,7 +21,10 @@ import { loadCliConfig } from '../../lib/config';
 import { ConfigSchema, ConfigVisibility } from '@backstage/config-loader';
 
 export default async (cmd: Command) => {
-  const { schema, appConfigs } = await loadCliConfig(cmd.config);
+  const { schema, appConfigs } = await loadCliConfig({
+    args: cmd.config,
+    fromPackage: cmd.package,
+  });
   const visibility = getVisiblityOption(cmd);
   const data = serializeConfigData(appConfigs, schema, visibility);
 

packages/cli/src/commands/config/validate.ts

@@ -18,5 +18,8 @@ import { Command } from 'commander';
 import { loadCliConfig } from '../../lib/config';
 
 export default async (cmd: Command) => {
-  await loadCliConfig(cmd.config);
+  await loadCliConfig({
+    args: cmd.config,
+    fromPackage: cmd.package,
+  });
 };

packages/cli/src/commands/index.ts

@@ -141,6 +141,10 @@ export function registerCommands(program: CommanderStatic) {
 
   program
     .command('config:print')
+    .option(
+      '--package <name>',
+      'Only load config schema that applies to the given package',
+    )
     .option('--frontend', 'Print only the frontend configuration')
     .option('--with-secrets', 'Include secrets in the printed configuration')
     .option(
@@ -153,6 +157,10 @@ export function registerCommands(program: CommanderStatic) {
 
   program
     .command('config:check')
+    .option(
+      '--package <name>',
+      'Only load config schema that applies to the given package',
+    )
     .option(...configOption)
     .description(
       'Validate that the given configuration loads and matches schema',

packages/cli/src/commands/plugin/serve.ts

@@ -14,15 +14,21 @@
  * limitations under the License.
  */
 
+import fs from 'fs-extra';
 import { Command } from 'commander';
 import { serveBundle } from '../../lib/bundler';
 import { loadCliConfig } from '../../lib/config';
+import { paths } from '../../lib/paths';
 
 export default async (cmd: Command) => {
+  const { name } = await fs.readJson(paths.resolveTarget('package.json'));
   const waitForExit = await serveBundle({
     entry: 'dev/index',
     checksEnabled: cmd.check,
-    ...(await loadCliConfig(cmd.config)),
+    ...(await loadCliConfig({
+      args: cmd.config,
+      fromPackage: name,
+    })),
   });
 
   await waitForExit();

packages/cli/src/lib/config.ts

@@ -18,14 +18,23 @@ import { loadConfig, loadConfigSchema } from '@backstage/config-loader';
 import { ConfigReader } from '@backstage/config';
 import { paths } from './paths';
 
-export async function loadCliConfig(configArgs: string[]) {
-  const configPaths = configArgs.map(arg => paths.resolveTarget(arg));
+type Options = {
+  args: string[];
+  fromPackage?: string;
+};
+
+export async function loadCliConfig(options: Options) {
+  const configPaths = options.args.map(arg => paths.resolveTarget(arg));
 
   // Consider all packages in the monorepo when loading in config
   const LernaProject = require('@lerna/project');
   const project = new LernaProject(paths.targetDir);
   const packages = await project.getPackages();
-  const localPackageNames = packages.map((p: any) => p.name);
+
+  const localPackageNames = options.fromPackage
+    ? findPackages(packages, options.fromPackage)
+    : packages.map((p: any) => p.name);
+
   const schema = await loadConfigSchema({
     dependencies: localPackageNames,
   });
@@ -61,3 +70,34 @@ export async function loadCliConfig(configArgs: string[]) {
     throw error;
   }
 }
+
+function findPackages(packages: any[], fromPackage: string): string[] {
+  const PackageGraph = require('@lerna/package-graph');
+
+  const graph = new PackageGraph(packages);
+
+  const targets = new Set<string>();
+  const searchNames = [fromPackage];
+
+  while (searchNames.length) {
+    const name = searchNames.pop()!;
+
+    if (targets.has(name)) {
+      continue;
+    }
+
+    const node = graph.get(name);
+    if (!node) {
+      throw new Error(`Package '${name}' not found`);
+    }
+
+    targets.add(name);
+
+    // Workaround for Backstage main repo only, since the CLI has some artificial devDependencies
+    if (name !== '@backstage/cli') {
+      searchNames.push(...node.localDependencies.keys());
+    }
+  }
+
+  return Array.from(targets);
+}