A Laravel Middleware that checks the system's current 15 minute loadavg and the number of CPUs, and if the resulting division is greater than 85%, returns 503 with an appropriate message.

overloaded.blade.php

{{-- resources/views/errors/overloaded.blade.php --}}

@extends('errors.layout')
@section('title', 'Server Overloaded')
@section('content')

	<div class="flex items-center pt-8 sm:justify-start sm:pt-0" style="width: max-content">
		<div class="border-r border-gray-400 text-lg tracking-wider text-gray-500" style="padding-right: 20px">
			503
		</div>

		<div class="text-lg uppercase tracking-wider text-gray-500" style="padding-left: 20px">
			Server Overloaded
		</div>
	</div>

	<div class="text-gray-500" style="font-size: small; margin-top: 12px">
		Please wait a minute and try again.
	</div>

@endsection

PreventOverloading.php

<?php

// app/Http/Middleware/PreventOverloading.php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Symfony\Component\HttpFoundation\Response;

/**
 * A Laravel Middleware that checks the system's current 15 minute
 * loadavg and the number of CPUs, and if the resulting division
 * is greater than 85%, returns 503 with an appropriate message.
 *
 * @license MIT 2024 Joe Koop
 */
class PreventOverloading {
	/**
	 * Handle an incoming request.
	 *
	 * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
	 */
	public function handle(Request $request, Closure $next): Response {
		// 15 min average
		$loadavg = `cat /proc/loadavg | awk '{print$3}'` / `cat /proc/cpuinfo | grep -E '^processor\s+:' | wc -l`;
		if ($loadavg > 0.85) {
			if ($request->acceptsHtml()) {
				return response(
					status: 503,
					headers: ["Refresh" => 10, "Retry-After" => 10],
					content: view("errors.overloaded"),
				);
			}
			abort(503, "Server Overloaded", ["Retry-After" => 10]);
		}
		return $next($request);
	}
}