Generate a "version number" for a PHP/Laravel application

helpers.php

<?php

use Carbon\Carbon;
use Illuminate\Support\Arr;

if (!function_exists('version')) {
    /**
     * Attempts to determine the current version of the application, based on `version` set in config/app.php and either
     * the file public/version.html (which should be created during the build process) or by exec'ing Git commands directly
     * at runtime. This results in a string of the format `<app-version>-<hash> (<last-modified>)`
     *   E.g: `7.0.0-81f63aa78c (2020-10-09 17:17:48)`
     *
     * @return string
     */
    function version(): string
    {
        $appVersion = config('app.version'); // Manually incremented in config/app.php when new feature released.
        $fileWithCommitHash = base_path('/public/version.html'); // Created during build process.

        if (file_exists($fileWithCommitHash)) {
            // Attempt to read values from public/version.html
            $values = explode("\n", file_get_contents($fileWithCommitHash));
            $commit = Arr::get($values, '0', 'unknown');
            if ($commitTime = Arr::get($values, '1')) {
                $commitTime = new Carbon($commitTime);
            } else {
                $commitTime = 'unknown';
            }
        } else {
            // File is not available so read from Git directly (NOTE: this will fail in staging/prod as the deployed assets
            // are inside a folder that is not a valid Git repo).
            if ($commit = trim(exec('git log --pretty="%h" -n1 HEAD'))) {
                if ($commitTime = trim(exec('git log -n1 --pretty=%ci HEAD'))) {
                    $commitTime = new Carbon($commitTime);
                    $commitTime->setTimezone('UTC');
                }
            }
        }

        // If for some reason we can't determine the app version, fallback to `unknown` for both values.
        $commit = !empty($commit) ? $commit : 'unknown';
        $commitTime = !empty($commitTime) ? $commitTime->format('Y-m-d H:i:s') : 'unknown';

        return "{$appVersion}-{$commit} ({$commitTime})";
    }
}