Capistrano and API keys in ENV variables?

Question

I'm deploying my rails app with Capistrano. I want to save some API keys on the server as an environment variable. Those API keys should be accessible to my rails app that is deployed with Capistrano. Those API keys should also be accessible to a separate ruby file that is run as a daemon.

setting the API keys in environment variables seems like the ideal solution, however, I can't access them in my rails app with ENV["SOME_KEY"].

According to this post, because capistrano runs as non interactive and non login, ~/.bashrc and ~/.bash_profile are not loaded. The flowchart suggests that I should use $BASH_ENV.

Can I just add my api keys in $BASH_ENV and access them in my rails app and in the ruby file that is a daemon with ENV["SOME_KEY"]?

I'm also thinking of just adding the api keys to a file somewhere on the server and symlinking it to the ruby file dir and rails dir and just open and reading it. Would this be possible?

Answer 1

There are a few ways that work well with Capistrano, in my experience.

rbenv-vars

If you use Ruby via Rbenv on your server, then you are in luck. There is a Rbenv plugin called rbenv-vars that automatically injects environment variables into any Ruby process, which would include your Rails app. Just add your variables to ~/.rbenv/vars on the server using KEY=value syntax. That's it.

dotenv

The dotenv gem is a similar solution, but it works as a gem you add to your Rails app and doesn't require Rbenv or any other supporting tools. Add dotenv-rails to your Gemfile and deploy. Dotenv will automatically look for a .env.production file in the root of your Rails app. For Capistrano, create a .env.production file on the server inside Capistrano's shared directory, and then add .env.production to :linked_files. Now every deploy will link to it. Declare your variables using KEY=value syntax.

.bashrc

Declare your variables with export KEY=value syntax at very top of the ~/.bashrc file on the server. On Ubuntu, this file is evaluated even during an non-interactive SSH session. Just make sure you place the declarations on the top, before this case statement:

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

CentOS may be a different story, so YMMV.

Answer 2

I made a Capistrano plugin capistrano-env_config some time ago for managing and syncing environment variables across a Capistrano cluster which works by modifying the /etc/environment file to make environment variables available throughout the system. It's easy to use and is similar to how you can set environment variables with the Heroku toolbelt. Here are some examples:

cap env:list
cap env:get[VARIABLE_NAME, VARIABLE_NAME, ...] 
cap env:unset[VARIABLE_NAME, VARIABLE_NAME, ...] 
cap env:set[VARIABLE_NAME=VALUE, VARIABLE_NAME=VALUE, ...] 
cap env:sync