To use custom environment variables in Opsworks follow the guide below:

This cookbook allows Rails apps on Amazon OpsWorks to separate their configuration from their code. In keeping with The twelve-factor app, the configuration is made available to the app's environment.

To accomplish this, the cookbook maintains a config/application.yml file in each respective app's deploy directory. E.g.:

---
SECRET_KEY_BASE: "xxxxxxxxxxxxx"
DB_PASSWORD: "123456789"

The application can then load its settings directly from this file, or use Figaro to automatically make these settings available in the app's ENV (strong recommended).

Configuration values are specified in the Amazon console but also a stack's custom JSON can be passed.

Example of the JSON that we have to pass in the AWS OpsWorks Portal inside: Stack -> Stack Settings -> Edit -> Custom JSON (in Advanced options section).

{  
  "deploy": {
    "app_name": {
      "symlink_before_migrate": {
        "config/application.yml": "config/application.yml"
      },
      "custom_env": {
        "DB_USERNAME": "foobar",
        "REDIS_URL":   "barfoo"
      }
    }
  }
}

Today we do not need to pass env variables using this JSON. We can only declare env variables in the AWS OpsWorks Portal, inside: Apps -> edit (app_name) -> Environment Variables.

Note that the symlink_before_migrate attribute is necessary so that OpsWorks automatically symlinks the shared file when setting up release directories or deploying a new version.

Caveats

At the moment, only default Opsworks configurations for Apache/Passenger and Unicorn/Nginx style Rails apps are supported.

Opsworks Set-Up

• Add custom_env and symlink_before_migrate attributes to the stack's custom JSON as in the example above.
• Associate the opsworks-cookbook-custom-env::custom_env recipe with the Deploy and Setup events in your rails app's layer.

A deploy isn't necessary if you just want to update the custom configuration. Instead, update the stack's custom JSON, then choose to Run Command > execute recipes and enter opsworks_custom_env::configure into the Recipes to execute field. Executing the recipe will write an updated application.yml file and restart unicorn workers.

Copyright and License

(c) 2016-2016 Diego Durante. See LICENSE for details.

Thanks to joeyAghion that inspired me.