Terraform template jsonencoding with iterate-CodePudding

I'm looking for a solution for this template to get the correct JSON file. As you may see in the sections, aws:RequestTag/*** lacks commas at the end. If I use the comma in the template, then I will have an unnecessary comma at the end of the last string.

I wonder the ${jsonencode()} should help, but I'm still not realizing how it's using with %{ for key in key_tag ~} together.

I would be appreciated for any help.

Terraform:

resource "local_file" "enforcetags" {
  content = templatefile("${path.module}/enforcetags.tpl",
    {
      key_tag = ["development_prod", "production_prod", "rnd_prod"]
    }
  )
  filename = "./enforce_tags.json"
}

Template:

    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Sid": "VisualEditor0",
                "Effect": "Allow",
                "Action": "ec2:*",
                "Resource": "*",
                "Condition": {
                    "ForAllValues:StringEquals": {
                        "aws:TagKeys": ${jsonencode([for key in key_tag : "${key}"])}
                    },
                    "StringEqualsIfExists": {
%{ for key in key_tag ~}
                    "aws:RequestTag/${key}": ${jsonencode([for key in key_tag : "${key}"])}
%{ endfor ~}
                    }
                }
            }
        ]
    }

Output:

    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Sid": "VisualEditor0",
                "Effect": "Allow",
                "Action": "ec2:*",
                "Resource": "*",
                "Condition": {
                    "ForAllValues:StringEquals": {
                        "aws:TagKeys": ["development_prod","production_prod","rnd_prod"]
                    },
                    "StringEqualsIfExists": {

                       "aws:RequestTag/development_prod": ["development_prod","production_prod","rnd_prod"]
                       "aws:RequestTag/production_prod": ["development_prod","production_prod","rnd_prod"]
                       "aws:RequestTag/rnd_prod": ["development_prod","production_prod","rnd_prod"]
                    
                    }
                }
            }
        ]
    }

CodePudding user response：

To have a comma at the end, except the last string it should be:

    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Sid": "VisualEditor0",
                "Effect": "Allow",
                "Action": "ec2:*",
                "Resource": "*",
                "Condition": {
                    "ForAllValues:StringEquals": {
                        "aws:TagKeys": ${jsonencode([for key in key_tag : "${key}"])}
                    },
                    "StringEqualsIfExists": ${jsonencode(
                                {for key in key_tag: "aws:RequestTag/${key}" => key_tag})}
                }
            }
        ]
    }