Format Count and for_each Resources

Formatting count and for_each

The count and for_each meta-arguments enable creating multiple instances of a resource. Formatting these correctly is important because the dynamic references (count.index, each.key, each.value) appear throughout the block.

count Example

resource "aws_subnet" "private" {
  count = length(var.private_subnet_cidrs)

  vpc_id            = aws_vpc.main.id
  cidr_block        = var.private_subnet_cidrs[count.index]
  availability_zone = var.availability_zones[count.index]

  tags = {
    Name = "private-subnet-${count.index}"
    Type = "private"
    AZ   = var.availability_zones[count.index]
  }
}

for_each with Map Example

resource "aws_iam_user" "team" {
  for_each = toset(var.team_members)

  name          = each.value
  path          = "/team/"
  force_destroy = true

  tags = {
    Team      = "engineering"
    ManagedBy = "terraform"
  }
}

resource "aws_s3_bucket" "environments" {
  for_each = {
    dev     = "us-east-1"
    staging = "us-east-1"
    prod    = "us-west-2"
  }

  bucket = "myapp-${each.key}-assets"

  tags = {
    Environment = each.key
    Region      = each.value
  }
}

Formatting Conventions

• Meta-argument first: count or for_each is always the first attribute in the block, separated by a blank line from other attributes
• Consistent references: count.index, each.key, and each.value references are kept on the same line as the attribute they populate
• Inline maps: When for_each uses an inline map, keys are aligned within the map block
• Tag alignment: Tags that mix static and dynamic values still have their equals signs aligned