Shared Variables

Shared Variables are configs that you define to affect how the templates are generated at compile-time. Shared variables are available to all templates, helpers, and parameters.


The variables are defined in the configs/BLUEPRINT/variables folder.

├── ecs-spot
│   └── variables
│       ├── development.rb
│       └── production.rb
└── vpc
    └── variables
        ├── development.rb
        └── production.rb


The variables files are merely Ruby scripts where instance variables (variables with an @ sign in front) are made available.

Here’s an example:


@ami = "ami-base"

The @ami variable is now available to all of your templates.

Here’s an another example:


@ami = "ami-production"

The @ami = "ami-production" variable will be used when LONO_ENV=production.

Variables allow you to affect the way your templates are built at compile time. This allows doing things that are outside of the ability of run-time parameters. Effective use of shared variables can dramatically shorten down your templates.

Stack Created

Layering Support

Variables also support layering. Layering support is covered in Layering Support.

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