Use file("${path.module}/iam.json") } but still able to use variables?

Terraform
1

Is is possible to use variables in json files direct?

See variable ${var.AWS_AccountID}:

resource "aws_iam_policy" "ebs" {
  name        = "test_policy"
  path        = "/"
  description = "EBS Access for eks"

  policy = file("${path.module}/iam.json")
}

iam.json

{
    "Version": "2012-10-17",
    "Statement": [
      {
        "Sid": "VisualEditor1",
        "Effect": "Allow",
        "Action": ["ec2:CreateVolume", "ec2:CreateTags"],
        "Resource": "arn:aws:ec2:eu-central-1:${var.AWS_AccountID}:volume/*"
      }
    ]
  }

Currently it dont get parsed. A working alternative is to use jsonencode() instead. But an own json file has the advantage to use the autoformatting, syntax check and features like editorconfig in Vscode.

2

You can use templatefile instead of file

1 Like
3

@stuart-c yes that worked, thanks. :slight_smile:

resource "aws_iam_policy" "ebs" {
  name        = "test_policy"
  path        = "/"
  description = "EBS Access for eks"

  policy = templatefile("${path.module}/IAM EBS.json",
    {
      AWS_AccountID = var.AWS_AccountID
    }
  )
}

{
    "Version": "2012-10-17",
    "Statement": [
      {
        "Sid": "VisualEditor1",
        "Effect": "Allow",
        "Action": ["ec2:CreateVolume", "ec2:CreateTags"],
        "Resource": "arn:aws:ec2:eu-central-1:${var.AWS_AccountID}:volume/*"
      }
    ]
  }