feat: bundle closing

cli/run/build.ts

@@ -62,6 +62,7 @@ export default async function build(
 	}
 
 	await Promise.all(outputOptions.map(bundle.write));
+	await bundle.close();
 	if (!silent) {
 		warnings.flush();
 		stderr(green(`created ${bold(files.join(', '))} in ${bold(ms(Date.now() - start))}`));

docs/02-javascript-api.md

@@ -10,6 +10,8 @@ The `rollup.rollup` function receives an input options object as parameter and r
 
 On a `bundle` object, you can call `bundle.generate` multiple times with different output options objects to generate different bundles in-memory. If you directly want to write them to disk, use `bundle.write` instead.
 
+Once you're finished with the `bundle` object, you can call `bundle.close`, which will let plugins clean up their external processes or services.
+
 ```javascript
 const rollup = require('rollup');
 
@@ -69,6 +71,9 @@ async function build() {
 
   // or write the bundle to disk
   await bundle.write(outputOptions);
+
+  // closes the bundle
+  await bundle.close();
 }
 
 build();

docs/05-plugin-development.md

@@ -251,6 +251,13 @@ Previous/Next Hook: This hook can be triggered at any time both during the build
 
 Notifies a plugin whenever rollup has detected a change to a monitored file in `--watch` mode. This hook cannot be used by output plugins. Second argument contains additional details of change event.  
 
+#### `closeBundle`
+Type: `closeBundle: () => Promise<void> | void`<br>
+Kind: `async, parallel`<br>
+Previous/Next Hook: This hook can be triggered at any time, during build errors or when `bundle.close()` is called, in which case this would be the last hook to be triggered.
+
+Can be used to clean up any external service that may be running, this hook is never run during watch mode.
+
 ### Output Generation Hooks
 
 Output generation hooks can provide information about a generated bundle and modify a build once complete. They work the same way and have the same types as [Build Hooks](guide/en/#build-hooks) but are called separately for each call to `bundle.generate(outputOptions)` or `bundle.write(outputOptions)`. Plugins that only use output generation hooks can also be passed in via the output options and therefore run only for certain outputs.

src/rollup/rollup.ts

@@ -2,7 +2,7 @@ import { version as rollupVersion } from 'package.json';
 import Bundle from '../Bundle';
 import Graph from '../Graph';
 import { ensureArray } from '../utils/ensureArray';
-import { errCannotEmitFromOptionsHook, error } from '../utils/error';
+import { errAlreadyClosed, errCannotEmitFromOptionsHook, error } from '../utils/error';
 import { writeFile } from '../utils/fs';
 import { normalizeInputOptions } from '../utils/options/normalizeInputOptions';
 import { normalizeOutputOptions } from '../utils/options/normalizeOutputOptions';
@@ -56,6 +56,7 @@ export async function rollupInternal(
 			err.watchFiles = watchFiles;
 		}
 		await graph.pluginDriver.hookParallel('buildEnd', [err]);
+		if (!watcher) await graph.pluginDriver.hookParallel('closeBundle', []);
 		throw err;
 	}
 
@@ -65,7 +66,17 @@ export async function rollupInternal(
 
 	const result: RollupBuild = {
 		cache: useCache ? graph.getCache() : undefined,
+		closed: false,
+		async close() {
+			if (result.closed) return;
+
+			result.closed = true;
+
+			await graph.pluginDriver.hookParallel('closeBundle', []);
+		},
 		async generate(rawOutputOptions: OutputOptions) {
+			if (result.closed) return error(errAlreadyClosed());
+
 			return handleGenerateWrite(
 				false,
 				inputOptions,
@@ -76,6 +87,8 @@ export async function rollupInternal(
 		},
 		watchFiles: Object.keys(graph.watchFiles),
 		async write(rawOutputOptions: OutputOptions) {
+			if (result.closed) return error(errAlreadyClosed());
+
 			return handleGenerateWrite(
 				true,
 				inputOptions,

src/rollup/types.d.ts

@@ -320,8 +320,12 @@ export type ResolveFileUrlHook = (
 export type AddonHookFunction = (this: PluginContext) => string | Promise<string>;
 export type AddonHook = string | AddonHookFunction;
 
-export type ChangeEvent = 'create' | 'update' | 'delete'
-export type WatchChangeHook = (this: PluginContext, id: string, change: {event: ChangeEvent}) => void
+export type ChangeEvent = 'create' | 'update' | 'delete';
+export type WatchChangeHook = (
+	this: PluginContext,
+	id: string,
+	change: { event: ChangeEvent }
+) => void;
 
 /**
  * use this type for plugin annotation
@@ -350,6 +354,7 @@ export interface OutputBundleWithPlaceholders {
 export interface PluginHooks extends OutputPluginHooks {
 	buildEnd: (this: PluginContext, err?: Error) => Promise<void> | void;
 	buildStart: (this: PluginContext, options: NormalizedInputOptions) => Promise<void> | void;
+	closeBundle: (this: PluginContext) => Promise<void> | void;
 	closeWatcher: (this: PluginContext) => void;
 	load: LoadHook;
 	moduleParsed: ModuleParsedHook;
@@ -412,7 +417,8 @@ export type AsyncPluginHooks =
 	| 'resolveDynamicImport'
 	| 'resolveId'
 	| 'transform'
-	| 'writeBundle';
+	| 'writeBundle'
+	| 'closeBundle';
 
 export type PluginValueHooks = 'banner' | 'footer' | 'intro' | 'outro';
 
@@ -447,7 +453,8 @@ export type ParallelPluginHooks =
 	| 'outro'
 	| 'renderError'
 	| 'renderStart'
-	| 'writeBundle';
+	| 'writeBundle'
+	| 'closeBundle';
 
 interface OutputPluginValueHooks {
 	banner: AddonHook;
@@ -740,6 +747,8 @@ export interface RollupOutput {
 
 export interface RollupBuild {
 	cache: RollupCache | undefined;
+	close: () => Promise<void>;
+	closed: boolean;
 	generate: (outputOptions: OutputOptions) => Promise<RollupOutput>;
 	getTimings?: () => SerializedTimings;
 	watchFiles: string[];
@@ -794,7 +803,7 @@ export interface RollupWatchOptions extends InputOptions {
 	watch?: WatcherOptions | false;
 }
 
-interface TypedEventEmitter<T extends {[event: string]: (...args: any) => any}> {
+interface TypedEventEmitter<T extends { [event: string]: (...args: any) => any }> {
 	addListener<K extends keyof T>(event: K, listener: T[K]): this;
 	emit<K extends keyof T>(event: K, ...args: Parameters<T[K]>): boolean;
 	eventNames(): Array<keyof T>;
@@ -827,7 +836,7 @@ export type RollupWatcherEvent =
 
 export interface RollupWatcher
 	extends TypedEventEmitter<{
-		change: (id: string, change: {event: ChangeEvent}) => void;
+		change: (id: string, change: { event: ChangeEvent }) => void;
 		close: () => void;
 		event: (event: RollupWatcherEvent) => void;
 		restart: () => void;

src/utils/PluginDriver.ts

@@ -47,6 +47,7 @@ const inputHookNames: {
 } = {
 	buildEnd: 1,
 	buildStart: 1,
+	closeBundle: 1,
 	closeWatcher: 1,
 	load: 1,
 	moduleParsed: 1,

src/utils/error.ts

@@ -65,7 +65,8 @@ export enum Errors {
 	UNRESOLVED_IMPORT = 'UNRESOLVED_IMPORT',
 	VALIDATION_ERROR = 'VALIDATION_ERROR',
 	EXTERNAL_SYNTHETIC_EXPORTS = 'EXTERNAL_SYNTHETIC_EXPORTS',
-	SYNTHETIC_NAMED_EXPORTS_NEED_NAMESPACE_EXPORT = 'SYNTHETIC_NAMED_EXPORTS_NEED_NAMESPACE_EXPORT'
+	SYNTHETIC_NAMED_EXPORTS_NEED_NAMESPACE_EXPORT = 'SYNTHETIC_NAMED_EXPORTS_NEED_NAMESPACE_EXPORT',
+	ALREADY_CLOSED = 'ALREADY_CLOSED'
 }
 
 export function errAssetNotFinalisedForFileName(name: string) {
@@ -377,6 +378,13 @@ export function errFailedValidation(message: string) {
 	};
 }
 
+export function errAlreadyClosed() {
+	return {
+		code: Errors.ALREADY_CLOSED,
+		message: "Bundle is already closed, no more calls to 'generate' or 'write' is allowed."
+	};
+}
+
 export function warnDeprecation(
 	deprecation: string | RollupWarning,
 	activeDeprecation: boolean,

test/hooks/index.js

@@ -1034,6 +1034,48 @@ describe('hooks', () => {
 			})
 			.then(bundle => bundle.generate({ format: 'es' })));
 
+	it('supports closeBundle hook', () => {
+		let closeBundleCalls = 0;
+		return rollup
+			.rollup({
+				input: 'input',
+				plugins: [
+					loader({ input: `alert('hello')` }),
+					{
+						closeBundle() {
+							closeBundleCalls++;
+						}
+					}
+				]
+			})
+			.then(bundle => bundle.close())
+			.then(() => {
+				assert.strictEqual(closeBundleCalls, 1);
+			});
+	});
+
+	it('calls closeBundle hook on build error', () => {
+		let closeBundleCalls = 0;
+		return rollup
+			.rollup({
+				input: 'input',
+				plugins: [
+					loader({ input: `alert('hello')` }),
+					{
+						buildStart() {
+							this.error('build start error');
+						},
+						closeBundle() {
+							closeBundleCalls++;
+						}
+					}
+				]
+			})
+			.catch(() => {
+				assert.strictEqual(closeBundleCalls, 1);
+			});
+	});
+
 	describe('deprecated', () => {
 		it('caches chunk emission in transform hook', () => {
 			let cache;