Terraform: Count parameter throws error with split interpolation function and map variable

[Deserved]

The snippet of code below will cause an error:

variable "api_public_subnets" {
  default = {
    cidrs = "a,b,c"
  }
}
resource "aws_subnet" "api_public_subnets" {
  ....
  count = "${length(split(",", var.api_public_subnets.cidrs))}"
  ....
}

Errors:

• strconv.ParseInt: parsing "${length(split(\",\", var.api_public_subnets.cidrs))}": invalid syntax

If I use not mapping it will work as expected, snippet of code below will work:

variable "api_public_subnets" {
  default = "a,b,c"

}
resource "aws_subnet" "api_public_subnets" {
  ....
  count = "${length(split(",", var.api_public_subnets))}"
  ....
}

For instance this code will work as-well, despite it uses mapping:

variable "api_public_subnets" {
  default = {
    cidrs = "a,b,c"
  }
}
resource "aws_subnet" "api_public_subnets" {
  ....
  tags {
    Application = "${length(split(",", var.api_public_subnets.cidrs))}"
  }
  ....
}

Is it a bug?

[jen20]

Hi @Deserved! Similarly to #3888, I can no longer reproduce this on master, using the following minimal reproduction:

provider "aws" {
  region = "us-west-2"
}

variable "api_public_subnets" {
  default = {
    cidrs = "a,b,c"
  }
}

resource "aws_subnet" "api_public_subnets" {
  cidr_block = "10.0.0.0/16"
  count      = "${length(split(",", var.api_public_subnets.cidrs))}"
}

Which version of Terraform are you using.

[Deserved]

Hi @jen20 I am using 0.6.6

I've just checked, it is more than 300 commits since 0.6.6 released to master. So probably it was fixed. Could you please try with 0.6.6 and see if you can replicate, if not it means problem in somewhere else.

[jrnt30]

@phinze @jen20 This is still occurring for me in 0.6.11 as well. As was alluded to in previous comments and in some of the related issues, it appears that this is related to the interpolation of a count parameter that is using a module's output.

I took the "hashicorp/best-practices" and extended it to provide a reproducible issue. Essentailly we were added an additional "peering" module which leverages outputs of the "public_subnets" and "private_subnets" modules. During the interpolation of the "count" parameter for the "aws_route" resource, we recieve the following * strconv.ParseInt: parsing "${length(split(\",\", var.pub_route_table_ids))}": invalid syntax

If I were to comment out the resource itself and take a look at the "interpolation_debug" output in the state, it is the appropriate value (and the plan proceeds as expected)

Diff: https://github.com/hashicorp/best-practices/compare/master...jrnt30:GH-3884-Module-interpolation-issues

Erroring Line: https://github.com/hashicorp/best-practices/compare/master...jrnt30:GH-3884-Module-interpolation-issues#diff-a40ed86341ef14520b793a2a198f68f6R31

Full debug log: https://gist.github.com/jrnt30/a55960ce3108639723bf

[jrnt30]

As a note, I made an attempt at "pre-computing" the length value in the "parent" module and passing in a set of "count" variables. In doing so, ran across #2301

I can provide another branch for that derivation of this issue if it's helpful

[haloflightleader]

Running into this issue also in Terraform v0.6.14

[norcalli]

And also on v0.6.15

[igor-pinchuk]

The same in Terraform v0.6.16

[mitchellh]

This works on master now with 0.7:

variable "foo" {
  default = {
    values = "a,b,c"
  }
}

resource "null_resource" "foo" {
  count = "${length(split(",", var.foo["values"]))}"
}

I think this is good to close.

[hashibot[bot]]

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