Context-based Variables

Terramate Lets Variables represent context-based variables that can be used in the surrounding attributes or blocks where it's defined. They are local to the parent block where they are defined and are never inherited in child directories. The Lets variables are recommended to not pollute the global namespace with temporary or intermediate variables.

Available contexts are:

• within generate_hcl blocks
• within generate_file blocks
• within [script](../../orchestration/scripts.md] blocks

They are defined the same way as Global Variables and support similar features.

lets {
  <variable-name> = <expression>
}

The following key differences exist compared to Terramate Globals:

• they are only available in some defined context e.g., generate_hcl and generate_file
• they do not support labels
• they support the additional let namespace in expressions

Example:

generate_file "file.json" {
  lets {
    # let.json is available in the current generate_file block only
    json = tm_jsonencode({ "hello" = "world" })
  }

  content = let.json
}