Readable logging for PHP

debug_log.php

/**
 * Writes a formatted line to the current environment's error log.
 *
 * @param mixed... $items_to_log One or more items to output to the log.
 *
 * @since 2020.2.0
 * @author Nick Brombal <[email protected]>
 */
function debug_log(...$items_to_log): void
{
    // Get the context for where the logging function was called.
    $log_context = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 1)[0];

    // Define an intro line for logs written with this function.
    $log_intro = "Logged output from {$log_context['file']}:{$log_context['line']}:" . CRLF;

    // Initialize the log contents.
    $log_content = '';

    foreach ($items_to_log as $item_index => $item_to_log) {
        // Add spaces between subsequent log items.
        if ($item_index > 0) {
            $log_content .= ' ';
        }

        // Append this item to the contents of the output, formatted as a
        // parsable string.
        $log_content .= var_export($item_to_log, true);
    }

    // Write to the log.
    error_log($log_intro . $log_content);
}