open-nomad/website/pages/docs/job-specification/hcl2/locals.mdx
Mahmood Ali d1e139c3fb
Docs for HCL2 (#9322)
Add more detailed HCL2 docs, mostly lifted from Packer with tweaks for Nomad.

The function docs are basically verbatim taken from Packer with basic string substitutions. I commented out some for_each details as the examples are mostly driven towards Packer resources. I'll iterate on those with better Nomad examples.
2020-11-29 20:36:41 -05:00

54 lines
1.7 KiB
Plaintext

---
layout: docs
page_title: Local Values - HCL Configuration Language
sidebar_title: Locals
description: >-
Local values assign a name to an expression that can then be used multiple
times within a folder.
---
# Local Values
`@include 'beta-nomad1.0-note.mdx'`
Local values assign a name to an expression, that can then be used multiple
times within a folder.
If [variables](/docs/job-specification/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}"
}
# Local values can be interpolated elsewhere using the "local." prefix.
job "${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.