Teardown compiler to improve rendering perf (#6391)

* Teardown compiler to improve rendering perf

* Upgrade compiler to minor

* Try hacky test guard

* Nicer teardown flow

.changeset/bright-forks-add.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Teardown compiler after Vite build to free up memory when rendering pages

packages/astro/package.json

@@ -99,7 +99,7 @@
     "test:e2e:match": "playwright test -g"
   },
   "dependencies": {
-    "@astrojs/compiler": "^1.1.0",
+    "@astrojs/compiler": "^1.2.0",
     "@astrojs/language-server": "^0.28.3",
     "@astrojs/markdown-remark": "^2.0.1",
     "@astrojs/telemetry": "^2.0.1",

packages/astro/src/cli/index.ts

@@ -203,7 +203,7 @@ async function runCommand(cmd: string, flags: yargs.Arguments) {
 		case 'build': {
 			const { default: build } = await import('../core/build/index.js');
 
-			return await build(settings, { ...flags, logging, telemetry });
+			return await build(settings, { ...flags, logging, telemetry, teardownCompiler: true });
 		}
 
 		case 'check': {

packages/astro/src/core/build/index.ts

@@ -18,13 +18,19 @@ import { apply as applyPolyfill } from '../polyfill.js';
 import { RouteCache } from '../render/route-cache.js';
 import { createRouteManifest } from '../routing/index.js';
 import { collectPagesData } from './page-data.js';
-import { staticBuild } from './static-build.js';
+import { staticBuild, viteBuild } from './static-build.js';
 import { getTimeStat } from './util.js';
+import { StaticBuildOptions } from './types.js';
 
 export interface BuildOptions {
 	mode?: RuntimeMode;
 	logging: LogOptions;
 	telemetry: AstroTelemetry;
+	/**
+	 * Teardown the compiler WASM instance after build. This can improve performance when
+	 * building once, but may cause a performance hit if building multiple times in a row.
+	 */
+	teardownCompiler?: boolean;
 }
 
 /** `astro build` */
@@ -42,13 +48,15 @@ class AstroBuilder {
 	private routeCache: RouteCache;
 	private manifest: ManifestData;
 	private timer: Record<string, number>;
+	private teardownCompiler: boolean;
 
 	constructor(settings: AstroSettings, options: BuildOptions) {
 		if (options.mode) {
 			this.mode = options.mode;
 		}
 		this.settings = settings;
 		this.logging = options.logging;
+		this.teardownCompiler = options.teardownCompiler ?? false;
 		this.routeCache = new RouteCache(this.logging);
 		this.origin = settings.config.site
 			? new URL(settings.config.site).origin
@@ -126,7 +134,7 @@ class AstroBuilder {
 			colors.dim(`Completed in ${getTimeStat(this.timer.init, performance.now())}.`)
 		);
 
-		await staticBuild({
+		const opts: StaticBuildOptions = {
 			allPages,
 			settings: this.settings,
 			logging: this.logging,
@@ -135,9 +143,13 @@ class AstroBuilder {
 			origin: this.origin,
 			pageNames,
 			routeCache: this.routeCache,
+			teardownCompiler: this.teardownCompiler,
 			viteConfig,
 			buildConfig,
-		});
+		};
+
+		const { internals } = await viteBuild(opts);
+		await staticBuild(opts, internals);
 
 		// Write any additionally generated assets to disk.
 		this.timer.assetsStart = performance.now();

packages/astro/src/core/build/static-build.ts

@@ -1,3 +1,4 @@
+import { teardown } from '@astrojs/compiler';
 import * as eslexer from 'es-module-lexer';
 import glob from 'fast-glob';
 import fs from 'fs';
@@ -25,7 +26,7 @@ import { registerAllPlugins } from './plugins/index.js';
 import type { PageBuildData, StaticBuildOptions } from './types';
 import { getTimeStat } from './util.js';
 
-export async function staticBuild(opts: StaticBuildOptions) {
+export async function viteBuild(opts: StaticBuildOptions) {
 	const { allPages, settings } = opts;
 
 	// Make sure we have an adapter before building
@@ -98,6 +99,17 @@ export async function staticBuild(opts: StaticBuildOptions) {
 
 	settings.timer.end('Client build');
 
+	// Free up memory
+	internals.ssrEntryChunk = undefined;
+	if (opts.teardownCompiler) {
+		teardown();
+	}
+
+	return { internals };
+}
+
+export async function staticBuild(opts: StaticBuildOptions, internals: BuildInternals) {
+	const { settings } = opts;
 	switch (settings.config.output) {
 		case 'static': {
 			settings.timer.start('Static generate');

packages/astro/src/core/build/types.ts

@@ -39,6 +39,7 @@ export interface StaticBuildOptions {
 	pageNames: string[];
 	routeCache: RouteCache;
 	viteConfig: InlineConfig;
+	teardownCompiler: boolean;
 }
 
 export interface SingleFileBuiltModule {