Should server/database config files, including pas

Question

I'm looking to hear some best practices...

Assuming a web application that interacts with a few different production servers (databases, etc.)... should the configuration files that include database passwords be stored in source control (e.g., git, svn)?

If not, what's the best way to keep track of server database (or other related) passwords that your application needs access to?

Edit: added a bounty to encourage more discussion and to hear what more people consider best practice.

Answer 1

Without a proper build process, I'm using this strategy (for PHP apps):

1. Make a folder /etc/companyname

2. In it, place two files:

   <?php // env.php
   return 'prod'; 
   

   <?php // appname-prod.php
   return array(
     'db' => array( /* credentials */ ),
     /* other host-specific conf data */
   ); 
   

3. Make both files readable only by your PHP process

Now your app's config file will be something like:

<?php // config.php
$env = (require "/etc/companyname/env.php");
$creds = (require "/etc/companyname/appname-{$env}.php");

With this in place, the environment defines the credentials used, and you can move code between pre-configured environments (and control some options with $env). This, of course, can be done with server environment variables, but this a) is simpler to setup and b) doesn't expose credentials to every script on the server (won't show up in a stray debugging junk like phpinfo()).

For easier reading outside PHP you could make the credential files JSON or something and just put up with the tiny performance hit (APC won't cache them).