How to fix error message when adding SQS redrive policy for deadletter queue created using for_each

Question

I want terraform to associate my SQS Management Event with my DLQ management event and i want the same thing done with SQS Data Event and DLQ Data Event.I am getting error messages when i run apply on my code below.please I need some help.

.tfvars

sqs_queue_names = ["CloudTrail_SQS_Management_Event", "CloudTrail_SQS_Data_Event"]

dead_queue_names = ["CloudTrail_DLQ_Management_Event", "CloudTrail_DLQ_Data_Event"]

main.tf

resource "aws_sqs_queue" "CloudTrail_SQS"{

    for_each                   = var.sqs_queue_names
    name                       = each.value
    redrive_policy = jsonencode({
        deadLetterTargetArn    = values(aws_sqs_queue.CloudTrail_SQS_DLQ)[*].arn
        maxReceiveCount        = var.max_receive_count
    })

    tags = var.default_tags
    
}

resource "aws_sqs_queue" "CloudTrail_SQS_DLQ"{

    for_each                   = var.dead_queue_names
    name                       = each.value
   
    tags = var.default_tags
}

Error: error creating SQS Queue (CloudTrail_SQS_Management_Event): InvalidParameterValue: Value {"deadLetterTargetArn":["arn:aws:sqs:us-east-1:123456789012:CloudTrail_DLQ_Data_Event","arn:aws:sqs:us-east-1:123456789012:CloudTrail_DLQ_Management_Event"],"maxReceiveCount":10} for parameter RedrivePolicy is invalid. Reason: Invalid value for deadLetterTargetArn.
│       status code: 400, request id: 9663b896-d86f-569e-92e2-e17152c2db26
│ 
│   with aws_sqs_queue.CloudTrail_SQS["CloudTrail_SQS_Management_Event"],
│   on main.tf line 5, in resource "aws_sqs_queue" "CloudTrail_SQS":
│    5: resource "aws_sqs_queue" "CloudTrail_SQS"{
│ 
╵
╷
│ Error: error creating SQS Queue (CloudTrail_SQS_Data_Event): InvalidParameterValue: Value {"deadLetterTargetArn":["arn:aws:sqs:us-east-1:123456789012:CloudTrail_DLQ_Data_Event","arn:aws:sqs:us-east-1:123456789012:CloudTrail_DLQ_Management_Event"],"maxReceiveCount":10} for parameter RedrivePolicy is invalid. Reason: Invalid value for deadLetterTargetArn.
│       status code: 400, request id: 88b8e4c5-1d50-5559-92f8-bd2297fd231f
│ 
│   with aws_sqs_queue.CloudTrail_SQS["CloudTrail_SQS_Data_Event"],
│   on main.tf line 5, in resource "aws_sqs_queue" "CloudTrail_SQS":
│    5: resource "aws_sqs_queue" "CloudTrail_SQS"{

Answer 1

There are few ways of doing this. One way would be as follows:

resource "aws_sqs_queue" "CloudTrail_SQS"{

    for_each                   = {for idx, val in var.sqs_queue_names: idx => val}
    name                       = each.value
    redrive_policy = jsonencode({
        deadLetterTargetArn    = values(aws_sqs_queue.CloudTrail_SQS_DLQ)[each.key].arn
        maxReceiveCount        = var.max_receive_count
    })

    tags = var.default_tags   
}

In the above, you create index variable as key for for_each and use that to reference DLQ values.