The build events file that I use with my 11ty build. It contains extensive logging that output to the Cloudflare pages build log.

build-events.js

import env from '../_data/env.js';
import { clearCssBuildCache } from '../_helpers/css-manipulation.js';
import { generatePreloadHeaders } from '../_helpers/header-generator.js';
import { compressHtmlFiles } from '../_helpers/html-compression.js';
import { compressJavaScriptFiles } from '../_helpers/js-compression.js';
import { minifyJavaScriptFiles } from '../_helpers/js-minify.js';

/**
 * Register eleventy.before and eleventy.after handlers.
 * Only registered when !env.isLocal (production/preview)
 * @param {import("@11ty/eleventy").UserConfig} eleventyConfig
 */
export function registerBuildEvents(eleventyConfig) {
	if (env.isLocal) {
		return;
	}

	eleventyConfig.on('eleventy.before', () => {
		clearCssBuildCache();
	});

	eleventyConfig.on('eleventy.after', async () => {
		console.log('\n═══════════════════════════════════════════════════════════════════════════════');
		console.log('🚀 PRODUCTION POSTBUILD PHASE: Beginning postbuild operations');
		console.log('═══════════════════════════════════════════════════════════════════════════════\n');
		generatePreloadHeaders();
		await minifyJavaScriptFiles();
		compressJavaScriptFiles();
		compressHtmlFiles();
		console.log('\n═══════════════════════════════════════════════════════════════════════════════');
		console.log('✅ PRODUCTION POSTBUILD PHASE: All postbuild operations completed');
		console.log('═══════════════════════════════════════════════════════════════════════════════\n');

		console.log('🔧 Forcing cleanup of HTTP connections and timers...');
		await new Promise(resolve => setTimeout(resolve, 100));

		try {
			const http = await import('http');
			const https = await import('https');

			if (http.globalAgent) {
				http.globalAgent.destroy();
				console.log('✅ Destroyed HTTP global agent');
			}
			if (https.globalAgent) {
				https.globalAgent.destroy();
				console.log('✅ Destroyed HTTPS global agent');
			}
		} catch (error) {
			console.warn('⚠️  Could not destroy HTTP agents:', error.message);
		}

		await new Promise(resolve => setTimeout(resolve, 50));
		console.log('✅ HTTP connection cleanup completed');

		if (env.isProd) {
			console.log('🏁 Production build complete - forcing process exit in 2 seconds...');
			setTimeout(() => {
				console.log('👋 Forcing clean exit now');
				process.exit(0);
			}, 2000);
		}
	});
}