perf: Log requests using high amount of memory as warning

Signed-off-by: Julius Knorr <jus@bitgrid.net>

lib/base.php

@@ -836,6 +836,21 @@ class OC {
 		register_shutdown_function(function () use ($eventLogger) {
 			$eventLogger->end('request');
 		});
+
+		register_shutdown_function(function () {
+			$memoryPeak = memory_get_peak_usage();
+			$logLevel = match (true) {
+				$memoryPeak > 500_000_000 => ILogger::FATAL,
+				$memoryPeak > 400_000_000 => ILogger::ERROR,
+				$memoryPeak > 300_000_000 => ILogger::WARN,
+				default => null,
+			};
+			if ($logLevel !== null) {
+				$message = 'Request used more than 300 MB of RAM: ' . \OCP\Util::humanFileSize($memoryPeak);
+				$logger = Server::get(LoggerInterface::class);
+				$logger->log($logLevel, $message, ['app' => 'core']);
+			}
+		});
 	}
 
 	/**