September 1, 2012

Set Project Specific Environment Variables with Pow

In your rails app, when you need an envionment variable like ENV['TWITTER_CONSUMER_KEY'] for local deveopment, where do you put them? Simply set them before you start your rails server as a one time thing, or just put them under ~/.profile or ~/.zshrc?

Well it works but I'm not happy with that. Because first it belongs to a specific project and expose them to global env make me feel a little bit uncomfortable, second, what if you happend to have more than one twitter integrated app, how do you name the variables to solve naming collision?

If you're using Pow, there is a perfect solution for you.

.powrc and .powenv

Pow provides these 2 files for you to config pow and setup any environment variables.

Before an application boots, Pow attempts to execute two scripts — first .powrc, then .powenv — in the application's root. Any environment variables exported from these scripts are passed along to Rack.

Convention here is putting .powrc under git version control, and override or setup any project specific environment variables to .powenv.

Let's do it

```diff .gitignore

```ruby .powenv

BTW, you must run this command to restart pow manually so these scripts will be loaded.

$ touch ~/.pow/restart.txt

[Pow Document: Customizing Environment Variables](
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Qihuan Piao

Qihuan Piao

(aka kinopyo) is Chinese based in Tokyo. Software writer. He shares stories inspired him in this blog. His infamous line - "I feel calm when I kill those monsters, or people (in game)" shocks his friends deeply.

He also writes in Japanese and Chinese.