Terraform: Support for nested maps in variables

Created on 28 May 2015  ·  82Comments  ·  Source: hashicorp/terraform

I'd love to be able to do this:

variable "amis" {
  default = {
    app1 = {
      us-west-2 = "ami-abc123"
    }
    app2 = {
      us-west-2 = "ami-cba321"
    }
  }
}

Currently, you'd get an error like Variable 'amis': must be string or mapping

config enhancement
Source
picture nevir
👍125

Most helpful comment

I just verified that the example given in the original comment on this issue works in Terraform v0.12-alpha1:

variable "amis" {
  default = {
    app1 = {
      us-west-2 = "ami-abc123"
    }
    app2 = {
      us-west-2 = "ami-cba321"
    }
  }
}

output "amis" {
  value = var.amis
}

In addition, Terraform v0.12 introduces the idea of _object types_ which allow specification of variables that expect a specific set of attributes that may be of different types:

variable "regions" {
  type = map(map(object({
    ami = string
  })))

  default = {
    app1 = {
      us-west-2 = {
        ami = "ami-abc123"
      }
    }
    app2 = {
      us-west-2 = {
        ami = "ami-cba321"
      }
    }
  }
}

output "regions" {
  value = var.regions
}

Although there is still a remaining small issue to fix over in #19141, this feature request is now complete. Thanks for your patience, everyone!

picture apparentlymart on 26 Oct 2018
👍27 🎉17 ❤11

All 82 comments

Interestingly, I can cheat a bit:

variable "amis" {
  default = {
    app.us-west-2 = "ami-abc123"
    app2.us-west-2 = "ami-cba321"
  }
}
nevir picture nevir on 28 May 2015

+1

jimmynapkins picture jimmynapkins on 20 Jul 2015

+1

bhouse picture bhouse on 21 Jul 2015

+1, I didn't realize this was not possible.

ketzacoatl picture ketzacoatl on 21 Jul 2015

+1

jbiel picture jbiel on 21 Jul 2015

+1

ojongerius picture ojongerius on 24 Jul 2015

+1

RBeaudoin picture RBeaudoin on 25 Aug 2015

:+1: really need to be able to pass data types other than strings in the DSL.

spheromak picture spheromak on 11 Sep 2015
👍5

+1

alexgervais picture alexgervais on 14 Sep 2015

+1 really need this one

sherabi picture sherabi on 1 Oct 2015

+1

quater picture quater on 6 Oct 2015

+1

OleksandrBerchenko picture OleksandrBerchenko on 28 Oct 2015

+1

rodlogic picture rodlogic on 6 Nov 2015

+1

Deserved picture Deserved on 12 Nov 2015

+1

ephemeral picture ephemeral on 8 Dec 2015

+1

craigwatson picture craigwatson on 17 Dec 2015

Being able to have a list as a value would also be very nice

bigkraig picture bigkraig on 1 Feb 2016

+1

giorgioprevitera picture giorgioprevitera on 20 Mar 2016

:+1:

jare19 picture jare19 on 6 Apr 2016

+1

mblankleder picture mblankleder on 15 Apr 2016

+1

vadanx picture vadanx on 27 Apr 2016

+1

simpsonjon picture simpsonjon on 5 May 2016

+1

multiloc picture multiloc on 19 May 2016

+1

eedwardsdisco picture eedwardsdisco on 22 May 2016

+1

gogs2k picture gogs2k on 6 Jun 2016

+1

JohnDzialo picture JohnDzialo on 23 Jun 2016

+1

balooo picture balooo on 27 Jun 2016

+1

ocsi01 picture ocsi01 on 28 Jun 2016

+1

thindiyeh picture thindiyeh on 30 Jun 2016

+1

ThomLambert picture ThomLambert on 30 Jun 2016

+1

drsolaris picture drsolaris on 1 Jul 2016

+1

asciifaceman picture asciifaceman on 6 Jul 2016

+1

dotariel picture dotariel on 11 Jul 2016

+1

iamseth picture iamseth on 25 Jul 2016

+1

madamedwards picture madamedwards on 28 Jul 2016

+1

lucasvasconcelos picture lucasvasconcelos on 29 Jul 2016

pleaseeeeeeeeee

jwerle picture jwerle on 1 Aug 2016

+1

alkema picture alkema on 5 Aug 2016

+1

deepshikhagandhi picture deepshikhagandhi on 10 Aug 2016

+1

adamjkeller picture adamjkeller on 17 Aug 2016

+1

erezesk picture erezesk on 21 Aug 2016

+1

dneff picture dneff on 22 Aug 2016

+1

iceycake picture iceycake on 23 Aug 2016

+1

arcadiatea picture arcadiatea on 23 Aug 2016

+1

SPhu picture SPhu on 29 Aug 2016

+1 any closer to this with 0.7 additional support for maps?

so we have lists and maps (+ maps of lists works?)

itsguy picture itsguy on 29 Aug 2016

+1

morkot picture morkot on 12 Sep 2016

+1

lamjo picture lamjo on 17 Sep 2016

Adding my vote for this.

related: #3690 #8384 #5841 #8153

blalor picture blalor on 30 Sep 2016

+1

MarcBittner picture MarcBittner on 10 Oct 2016
👍1

+1

grebois picture grebois on 13 Oct 2016

+1

jtrinklein picture jtrinklein on 20 Oct 2016

+1

oleksiidzhulai picture oleksiidzhulai on 14 Dec 2016

+1

nfernal picture nfernal on 7 Jan 2017

+1

walterdolce picture walterdolce on 26 Jan 2017

+1

randahlem picture randahlem on 2 Feb 2017

+1
gosh! :)

petrem picture petrem on 6 Feb 2017

+1

hsingh6764 picture hsingh6764 on 8 Feb 2017

+1

russmac picture russmac on 10 Feb 2017

+1

ceqi picture ceqi on 17 Feb 2017

+1

lisfo4ka picture lisfo4ka on 17 Feb 2017

👍

fbueno picture fbueno on 24 Feb 2017

+1

sprutner picture sprutner on 5 Mar 2017

+1

jsvazic picture jsvazic on 6 Mar 2017

+1

maxsakharov picture maxsakharov on 8 Mar 2017

+1

austinjones picture austinjones on 8 Mar 2017

+1

andrleite picture andrleite on 10 Mar 2017

+1

jzakrzeski picture jzakrzeski on 14 Mar 2017

+1 This would be really helpful when it comes to tags.

geekmuse picture geekmuse on 15 Mar 2017

+1

mubeta06 picture mubeta06 on 15 Mar 2017

+1

sjauld picture sjauld on 15 Mar 2017

+1

jtsaito picture jtsaito on 16 Mar 2017

+1

What are people doing to work around this?

tomstockton picture tomstockton on 16 Mar 2017

@tomstockton it's been two years, had to drop terraform originally and then brought it back in a lesser capacity

asciifaceman picture asciifaceman on 16 Mar 2017

Here is what I would do as an alternative for this map of map issue:

variable amis {
    app1 = "app1_map"
    app2 = "app2_map"
}
app1_map = {
      us-west-2 = "ami-abc123"
}
app2_map = {
      us-west-2 = "ami-cba321"
    }
}
Hua2308 picture Hua2308 on 17 Mar 2017

Here's what I did for multi-environment in one variables.tf file symlinked into each environment folder

variable "subnets" {
    type = "map"
    default = {
        dev             = "10.104.0.0/16"
        qa              = "10.103.0.0/16"
        stage           = "10.102.0.0/16"
        prod            = "10.101.0.0/16"
        app.dev         = "10.104.20.0/23"
        app.qa          = "10.103.20.0/23"
        app.stage       = "10.102.20.0/23"
        app.prod        = "10.101.20.0/23"
        app_1.dev       = "10.104.20.0/24"
        app_1.qa        = "10.103.20.0/24"
        app_1.stage     = "10.102.20.0/24"
        app_1.prod      = "10.101.20.0/24"
        app_2.dev       = "10.104.21.0/24"
        app_2.qa        = "10.103.21.0/24"
        app_2.stage     = "10.102.21.0/24"
        app_2.prod      = "10.101.21.0/24"
        public.dev      = "10.104.10.0/23"
        public.qa       = "10.103.10.0/23"
        public.stage    = "10.102.10.0/23"
        public.prod     = "10.101.10.0/23"
        public_1.dev    = "10.104.10.0/24"
        public_1.qa     = "10.103.10.0/24"
        public_1.stage  = "10.102.10.0/24"
        public_1.prod   = "10.101.10.0/24"
        public_2.dev    = "10.104.11.0/24"
        public_2.qa     = "10.103.11.0/24"
        public_2.stage  = "10.102.11.0/24"
        public_2.prod   = "10.101.11.0/24"
        private_1.dev   = "10.104.xx.0/24"
        private_1.qa    = "10.103.xx.0/24"
        private_1.stage = "10.102.xx.0/24"
        private_1.prod  = "10.101.xx.0/24"
        private_2.dev   = "10.104.xx.0/24"
        private_2.qa    = "10.103.xx.0/24"
        private_2.stage = "10.102.xx.0/24"
        private_2.prod  = "10.101.xx.0/24"
    }
}

and then call it like 

module "vpc" {
  source = "../modules/aws_vpc/"

  # we call the environment 'variable' here for the vpc name

  name          = "vpc-${var.environment}"

  cidr                    = "${lookup(var.subnets, var.environment)}"
  private_subnets         = ["${lookup(var.subnets, "private_1.${var.environment}")}", "${lookup(var.subnets, "private_2.${var.environment}")}"]
  public_subnets          = ["${lookup(var.subnets, "public_1.${var.environment}")}", "${lookup(var.subnets, "public_2.${var.environment}")}"]
  app_subnets             = ["${lookup(var.subnets, "app_1.${var.environment}")}", "${lookup(var.subnets, "app_2.${var.environment}")}"]
  enable_dns_hostnames    = true
  enable_dns_support      = true
  enable_nat_gateway      = "true"
}
sprutner picture sprutner on 21 Mar 2017

+1

mtoriumi picture mtoriumi on 26 Apr 2017

+1

mossy02 picture mossy02 on 5 May 2017

+1

nilo picture nilo on 11 May 2017

I just verified that the example given in the original comment on this issue works in Terraform v0.12-alpha1:

variable "amis" {
  default = {
    app1 = {
      us-west-2 = "ami-abc123"
    }
    app2 = {
      us-west-2 = "ami-cba321"
    }
  }
}

output "amis" {
  value = var.amis
}

In addition, Terraform v0.12 introduces the idea of _object types_ which allow specification of variables that expect a specific set of attributes that may be of different types:

variable "regions" {
  type = map(map(object({
    ami = string
  })))

  default = {
    app1 = {
      us-west-2 = {
        ami = "ami-abc123"
      }
    }
    app2 = {
      us-west-2 = {
        ami = "ami-cba321"
      }
    }
  }
}

output "regions" {
  value = var.regions
}

Although there is still a remaining small issue to fix over in #19141, this feature request is now complete. Thanks for your patience, everyone!

apparentlymart picture apparentlymart on 26 Oct 2018
👍27 🎉17 ❤11

Here's what I did for multi-environment in one variables.tf file symlinked into each environment folder

variable "subnets" {
    type = "map"
    default = {
        dev             = "10.104.0.0/16"
        qa              = "10.103.0.0/16"
        stage           = "10.102.0.0/16"
        prod            = "10.101.0.0/16"
        app.dev         = "10.104.20.0/23"
        app.qa          = "10.103.20.0/23"
        app.stage       = "10.102.20.0/23"
        app.prod        = "10.101.20.0/23"
        app_1.dev       = "10.104.20.0/24"
        app_1.qa        = "10.103.20.0/24"
        app_1.stage     = "10.102.20.0/24"
        app_1.prod      = "10.101.20.0/24"
        app_2.dev       = "10.104.21.0/24"
        app_2.qa        = "10.103.21.0/24"
        app_2.stage     = "10.102.21.0/24"
        app_2.prod      = "10.101.21.0/24"
        public.dev      = "10.104.10.0/23"
        public.qa       = "10.103.10.0/23"
        public.stage    = "10.102.10.0/23"
        public.prod     = "10.101.10.0/23"
        public_1.dev    = "10.104.10.0/24"
        public_1.qa     = "10.103.10.0/24"
        public_1.stage  = "10.102.10.0/24"
        public_1.prod   = "10.101.10.0/24"
        public_2.dev    = "10.104.11.0/24"
        public_2.qa     = "10.103.11.0/24"
        public_2.stage  = "10.102.11.0/24"
        public_2.prod   = "10.101.11.0/24"
        private_1.dev   = "10.104.xx.0/24"
        private_1.qa    = "10.103.xx.0/24"
        private_1.stage = "10.102.xx.0/24"
        private_1.prod  = "10.101.xx.0/24"
        private_2.dev   = "10.104.xx.0/24"
        private_2.qa    = "10.103.xx.0/24"
        private_2.stage = "10.102.xx.0/24"
        private_2.prod  = "10.101.xx.0/24"
    }
}

and then call it like

module "vpc" {
  source = "../modules/aws_vpc/"

  # we call the environment 'variable' here for the vpc name

  name          = "vpc-${var.environment}"

  cidr                    = "${lookup(var.subnets, var.environment)}"
  private_subnets         = ["${lookup(var.subnets, "private_1.${var.environment}")}", "${lookup(var.subnets, "private_2.${var.environment}")}"]
  public_subnets          = ["${lookup(var.subnets, "public_1.${var.environment}")}", "${lookup(var.subnets, "public_2.${var.environment}")}"]
  app_subnets             = ["${lookup(var.subnets, "app_1.${var.environment}")}", "${lookup(var.subnets, "app_2.${var.environment}")}"]
  enable_dns_hostnames    = true
  enable_dns_support      = true
  enable_nat_gateway      = "true"
}

FYI: Terraform v0.12 will complain about the ' . ' in the subnet variables (e.g app.dev) with this error:
Error: Ambiguous attribute key
I changed the ' . ' delimiter and works fine.

arbreezy picture arbreezy on 30 Jul 2019

I'm going to lock this issue because it has been closed for _30 days_ ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.

hashibot[bot] picture hashibot[bot] on 31 Jul 2019
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