Creating an additional AWS policy within a lambda child module gives invalid index

Question

Forgive me if this question is a little basic, I'm quite new to both AWS and Terraform.

I'm trying to create a lambda function via a terraform module. The source of the module is pointing at this repo https://github.com/terraform-aws-modules/terraform-aws-lambda/tree/master.

I am trying to follow the complete example provided starting at 130 of terraform-aws-lambda/examples/complete/main.tf but in my case I need to set 2 policies rather than 1.

I have:

   number_of_policy_jsons = 2

   policy_jsons = [
    <<-EOT
      {
          "Version": "2012-10-17",
          "Statement": [
              {
                  "Effect": "Allow",
                  "Action": [
                      "xray:*"
                  ],
                  "Resource": ["*"]
              }
          ]
      },
      {
          "Version": "2012-10-17",
          "Statement": [
              {
                  "Effect": "Allow",
                  "Action": [
                      "s3:*"
                  ],
                  "Resource": ["*"]
              }
          ]
      }
    EOT
  ]

I'm guessing I've formatted the json incorrectly but I can not figure out how it is supposed to be done. No matter what I try I get this error.

     Error: Invalid index
    │ 
    │  126:   policy = var.policy_jsons[count.index] 
    │     ├────────────────
    │     │ count.index is 1
    │     │ var.policy_jsons is list of string with 1 element
    │ 
    │ The given key does not identify an element in this collection value: the given index is greater than or
    │ equal to the length of the collection.

If someone could explain how this is supposed to be used that would be so helpful.

Can you add the entire module call to the question? – Marko E Jul 19 '23 at 06:37 — Marko E, Jul 19 '23 at 06:37

score 1 · Accepted Answer · answered Jul 19 '23 at 07:48

Hey you should format your list like this :

policy_jsons = [<<EOF
{
      "Version": "2012-10-17",
      "Statement": [
          {
              "Effect": "Allow",
              "Action": [
                  "xray:*"
              ],
              "Resource": ["*"]
          }
      ]
  }
EOF,
<<EOF
{
      "Version": "2012-10-17",
      "Statement": [
          {
              "Effect": "Allow",
              "Action": [
                  "s3:*"
              ],
              "Resource": ["*"]
          }
      ]
  }
EOF

]

It's not very pretty to look at, another solution is to us Data Source: aws_iam_policy_document

data "aws_iam_policy_document" "xray" {
    statement {
        actions = ["xray:*"]
        resources = ["*"]
    }
}
data "aws_iam_policy_document" "s3" {
    statement {
        actions = ["s3:*"]
        resources = ["*"]
    }
}

and then

policy_jsons = [
    data.aws_iam_policy_document.xray.json,
    data.aws_iam_policy_document.s3.json
]

Creating an additional AWS policy within a lambda child module gives invalid index

1 Answers1