#Knative Variables

Variables allow users to dynamically replace config values in serverless.yml config. They are especially useful when providing secrets for your service to use and when you are working with multiple stages.

The Serverless Framework provides a powerful variable system which allows you to add dynamic data into your serverless.yml. With Serverless Variables, you'll be able to do the following:

• Reference & load variables from environment variables via ${env:FOO}
• Reference & load variables from CLI options via ${opt:stage}
• Recursively reference properties of any type from the same serverless.yml file via ${self:provider.name}
• Recursively reference properties of any type from other YAML / JSON files via ${file(../some-file.json):exportedVar}
• Recursively nest variable references within each other for ultimate flexibility
• Combine multiple variable references to overwrite each other

Note: You can only use variables in serverless.yml property values, not property keys. So you can't use variables to generate dynamic logical IDs in the custom resources section for example.