Prevent file differences between live and staging websites AND system scripts (PHP)

Question

I'm trying to find a good way to maintain PHP configuration differences between a dev and live environment. I know how to handle differences when scripts are run by Apache (see below), but not when they are run on the command line, e.g. via cron.

Background info:

What do I mean by "configuration differences"? Like most code shops, we run a non-public 'staging' version of our website where we test code before it goes to the live website. We use Subversion and have the live website as 'Trunk' and 'Staging' as a branch. It makes life easier when code goes from staging to live if the repository version of the files have minimal differences. But obviously, some details need to be different, e.g. the DB connection details.

How configuration differences are solved with Apache

In PHP, we set branch specific variables as follows:

switch ($_SERVER['HTTP_HOST']) {
    case 'ourstagingurl.com':
        $dbPassword = "blahblah";
        break;
    default:
        $dbPassword = "blahblah";
}

or we put the following in the .htaccess file relevant to the specific site:

php_value dbPassword "blahblah"

Why I can't resolve configuration differences using the CLI?

When a script is run on the CLI, there's no super globals such as $_SERVER. I could include a config file using a absolute path but how can I know whether the script is from live or staging? I could pass in a command line argument that specifies the environment but I was hoping there was a better way?

Answer 1

Hey, I work for a company with a similar setup. What I generally do is set up a scenerio where the staging and live servers both modify a common and generic config file. When the site is deployed on both the staging and live the information will be incorrect and will need to be modified once in each location. However, this will ONLY need to happen once because the parts you modify will be noted as modified by subversion and will not be overwritten by subversion in subsequent svn updates.

Answer 2

$host = isset( $_SERVER['HTTP_HOST'] ) ? $SERVER_['HTTP_HOST'] : php_uname('n');

switch ( $host ) 
{
    case 'ourstagingurl.com':
        $dbPassword = "blahblah";
        break;
    default:
        $dbPassword = "blahblah";
}

If php version is => 5.3 then gethostname() could be used instead.

Answer 3

You can do as Jurassic suggested, or you can set an environment variable and read it in through $_ENV.

Answer 4

If live and staging are the same server (why don' t you use virtualisation?) then you'll probably have to resort to passing arguments to your scripts ie. call php script.php staging for staging and php script.php live for live site. BTW In case you wouldn' t know, the arguments are accessible using $argv in your PHP script -> http://www.php.net/manual/en/reserved.variables.argv.php.

Though maybe you could get part of the path of the file and use that as your "environment". ie. when file layout is /project/staging/script.php for staging and /project/live/script.php for live it should be easy to get the environment from the script itself using dirname(__FILE __) - extra space after FILE needs to be removed - and stripping the /project folder from it. Pretty stupid but it will work :p.

Answer 5

In some of my applications, I attempt to include a file that only exists to override values on the development server. I use the dreaded @ operator, but you could do an is_file() as well.

@include 'includes/debug.php';

debug.php would attempt to set some variables:

define('DEBUG', true);
define('DB_PASSWORD', 'foobar');

I tell svn to ignore this file. It sticks around in my development checkout, and has a minimal impact on production.

More generally I use hostname checking as it works in both CLI and web apps, but you've stated you have both branches on the same box, so that's out.