CODEWITHSUNDEEP
terraformterraform0.12+
debek
debek

Reputation: 389

List issue during upgrade from Terraform 0.11 to 0.12

I have a problem trying to rewrite a list to work in Terraform 0.12 that works in Terraform 0.11.

This is my list:

variable "master_authorized_networks_config" {
  type        = list(string)
  description = "The list of CIDR blocks of master authorized networks."

  default = [
    {
      cidr_blocks = [
        { 
          cidr_block   = "XXXXXX/32"
          display_name = "XXXXX"
        },
        { 
          cidr_block   = "XXXXXX/32"
          display_name = "XXXXX"
        },
        { 
          cidr_block   = "XXXXXX/32"
          display_name = "XXXXX"
        },
        { 
          cidr_block   = "XXXXXX/32"
          display_name = "XXXXX"
        },
      ]
    },
  ]

I added it to module: master_authorized_networks_config = var.master_authorized_networks_config

After running terraform apply I get the following error:

Error: Invalid default value for variable

  on ../../modules/xxx/xxx/variables.tf line 71, in variable "master_authorized_networks_config":
  71:   default = [
  72:     {
  73:       cidr_blocks = [
  74:         {
  75:           cidr_block   = "XXXXXX/32"
  76:           display_name = "XXXXX"
  77:         },
  78:         {
  79:           cidr_block   = "XXXXXX/32"
  80:           display_name = "XXXXX"
  81:         },
  82:         {
  83:           cidr_block   = "XXXXXX/32"
  84:           display_name = "XXXXX"
  85:         },
  86:         {
  87:           cidr_block   = "XXXXXX/32"
  88:           display_name = "XXXXX"
  89:         },
 102:       ]
 103:     },
 104:   ]

This default value is not compatible with the variable's type constraint:
element 0: string required.

I can't resolve this problem. Can you help me?

Upvotes: 1

Views: 1177

Answers (1)

ydaetskcoR
ydaetskcoR

Reputation: 56859

The error is telling you that your default value doesn't match the type constraint that you've told Terraform about with type = list(string). That type constraint says that it must be a list of strings and is the default coming from 0.11 via the 0.12upgrade tool that you may have ran to get that output if you had type = list previously.

You could change your type constraint to be list(object). If you simplified your data structure so that you just had a list of objects with cidr_block and display_name keys instead of a list of objects with key cidr_blocks that has a list of the aforementioned objects then you could even go as far as validating that more precisely:

variable "master_authorized_networks_config" {
  type = list(object{
    cidr_block   = string
    display_name = string
  })

  description = "The list of CIDR blocks of master authorized networks."

  default = [
    { 
      cidr_block   = "XXXXXX/32"
      display_name = "XXXXX"
    },
# ...
  ]
}

Or, much simpler, when providing a default you can choose to let Terraform infer the expected object type automatically by removing the type parameter from the variable. Then if anyone attempts to pass in a variable that doesn't match the type of the default Terraform will tell you at plan or validate time.

Upvotes: 3

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