ActionMailer password security

Question

Am I crazy, or is it a bad idea to keep my SMTP username and password for ActionMailer in the actual (development/production) config file? It seems like I should store it an encrypted place, or at the very minimum, exclude it from my Mercurial pushes. Right now, I'm just removing the password from my source file before performing a push, but there's got to be a smarter way than the one I'm using. :) Perhaps I should store it in my database as another user (which is already stored with encrypted passwords) and fetch it programatically?

Accepted Answer

Use an application configuration file that is not stored in your repository for storing sensitive information. Here is how I've done it:

Add an `app_config.yml` in your `config` directory. Its contents would look like this:

```
smtp_password: kl240jvfslkr32rKgjlk
some_other_password: 34hg9r0j0g402jg
and_so_on: lkn$@gJkjgsFLK4gaj
```

Add a `preinitializer.rb` in your `config` directory with the following contents:

```
require 'yaml'
APP_CONFIG = YAML.load(File.read(RAILS_ROOT + "/config/app_config.yml"))
```

Substitute your passwords for values in the `APP_CONFIG` variable, like so:

```
smtp_password = kl240jvfslkr32rKgjlk # old version
smtp_password = APP_CONFIG['smtp_password'] # new version
```

Make sure you don't include `app_config.yml` in your repository, though you may want to create an example file that is checked in, just to show a sample of what should be in it. When you deploy your application, make sure that `app_config.yml` is stored on the server. If you're using a standard Capistrano deployment, put the file in the shared folder and update your deployment task to create a symlink to it in the current release's directory.

ActionMailer password security

Solution

Problem