terraform templatefile and handling tags for cloudformation yaml

terraform-templatefile-tag-cloudformation.md

I used the following code block to add Tags into Cloudformation yaml file.

 %{~ if length(mytags) >0 ~}
      Tags:
     %{~ endif ~}
    %{~ for tag_key, tag_value in mytags ~}
        - Key: "${tag_key}"
          Value: "${tag_value}"
    %{~ endfor ~}
    

I had to put ~ before } and after { for each control lines to avoid having extra new lines for each tag key, value.

sample terraform code block:

variable "tags" {
  description = "A list of tags to apply to fleet."
  type        = map(string)
  default = {
    "Tag1" = "value1"
    "Tag2" = "value2"
    "Tag3" = "value3"
  }
}

resource "aws_cloudformation_stack" "appstream" {
  count = var.enable_appstream == true ? 1 : 0
  name  = "appstream-${var.stack_name}"
  tags  = var.tags
  parameters = {
    StackName                      = var.stack_name
    FleetName                      = var.fleet_name
    FleetType                      = var.fleet_type
    ImageName                      = var.appstream_image_name
    InstanceType                   = var.instance_type
    DesiredInstances               = var.no_of_instance
    SubnetIds                      = var.subnet_ids
    SecurityGroupIds               = var.security_group_ids
    StreamView                     = var.stream_view
    DisconnectTimeoutInSeconds     = var.disconnect_timeout_in_seconds
    IdleDisconnectTimeoutInSeconds = var.idle_disconnect_timeout_in_seconds

  }

  template_body = templatefile("${path.module}/cloudformation.yaml", { mytags = var.tags, stack_name = var.stack_name })
}

sample cloudformation.yaml

Resources:
  AppStreamFleet:
    Type: "AWS::AppStream::Fleet"
    Properties:
      Name: !Ref FleetName
      Description: !Ref FleetName
      ImageName: !Ref ImageName
      InstanceType: !Ref InstanceType
      FleetType: !Ref FleetType
      StreamView: !Ref StreamView
      ComputeCapacity:
        DesiredInstances: !Ref DesiredInstances
      VpcConfig:
        SubnetIds: !Ref SubnetIds
        SecurityGroupIds: !Ref SecurityGroupIds
      MaxUserDurationInSeconds: "57600"
      DisconnectTimeoutInSeconds: !Ref DisconnectTimeoutInSeconds
      IdleDisconnectTimeoutInSeconds: !Ref IdleDisconnectTimeoutInSeconds
      EnableDefaultInternetAccess: true
      %{~ if length(mytags) >0 ~}
      Tags:
     %{~ endif ~}
    %{~ for tag_key, tag_value in mytags ~}
        - Key: "${tag_key}"
          Value: "${tag_value}"
    %{~ endfor ~}
    CreationPolicy:
      StartFleet: True

when you do terraform apply,the YAML content will be like the following:

                  IdleDisconnectTimeoutInSeconds: !Ref IdleDisconnectTimeoutInSeconds
                  EnableDefaultInternetAccess: true
                  Tags:
                    - Key: "Tag1"
                      Value: "value1"
                    - Key: "Tag2"
                      Value: "value2"
                    - Key: "Tag3"
                      Value: "value3"
                CreationPolicy:
                  StartFleet: True
                  ```