See Variables in the docs.

Note you can’t define variables in the REPL as per issue you can access existing variables and you can run functions on a literal.

Types

Basic

  • string
  • number
  • bool

Structures

  • list(<TYPE>)
  • set(<TYPE>)
  • map(<TYPE>)
  • object({<ATTR NAME> = <TYPE>, ... })
  • tuple([<TYPE>, ...])

Definition

variable "image_id" {
  type        = string
  description = "..."
}

variable "image_id" {
  type        = string
  description = "..."

  validation {
    condition     = can(regex("^foo-", var.image_id))
    error_message = "The image_id value must be a valid foo id, starting with \"foo-\"."
  }
}

Maps

Create

{ a: 1 }
{ "a": 1 }

Get

These will give an error if the key is not set, except for the last which sets a default value.

bar.foo
bar["foo"]

lookup(bar, "foo")
# Set default.
lookup(bar, "foo", null)

Here, bar is of type inputMap and you need to use .value to get a map or you’ll get an error.

foo = lookup(bar.value, "foo")
foo = bar.value.foo
foo = bar.value["foo"]

Dynamic blocks

Before of external modules, you might have to deprecate using an array.

foo = [
  {
    a = 1
  },
  {
    a = 2
  }
]

And use a block instead:

foo {
  a = 1
}
foo {
   = 2
}

You can convert an array into a block using the dynamic block syntax.

dynamic "foo" {
    for_each = var.foos
    content {
      a = foo.value["a"]
    }
}

Then you pass in foos as your array in your TF vars file and it will unpack each as a foo element. Each item in the for loop will use the name given such as "foo".