nomad/website/content/docs/reference/hcl2/locals.mdx

---
layout: docs
page_title: HCL locals reference
description: |-
  Local values assign a name to an expression that can then be used multiple
  times within a folder.
---

# HCL locals reference

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

If [variables](/nomad/docs/reference/hcl2/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:

```hcl
# 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.