HCL locals reference

Local values assign a name to an expression, that can then be used multiple times within a folder.

If variables are analogous to function arguments then local values are comparable to a function's local variables.

Examples

Local values are defined in locals blocks:

# A computed default name prefix
locals {
  default_name_prefix = "${var.project_name}-web"
  name_prefix         = "${var.name_prefix != "" ? var.name_prefix : local.default_name_prefix}"

  # unlike variables, locals don't have type constraints, so if you use
  # functions that take maps but not objects, you may need to convert them
  number_of_ports = length(convert({"www" = "80"}, map(string)))
}

# Local values can be interpolated elsewhere using the "local." prefix.
job "example_loadbalancer" {
  name = "${local.name_prefix}_loadbalancer"
  # ...
}

Description

The locals block defines one or more local variables.

The names given for the items in the locals block must be unique. The given value can be any expression that is valid within the current file.

The expression of a local value can refer to other locals, but reference cycles are not allowed. That is, a local cannot refer to itself or to a variable that refers (directly or indirectly) back to it.

It's recommended to group together logically-related local values into a single block, particularly if they depend on each other. This will help the reader understand the relationships between variables. Conversely, prefer to define unrelated local values in separate blocks, and consider annotating each block with a comment describing any context common to all of the enclosed locals.