Terraform: [AWS] Pass tags to module creating an ASG

[mcinteer]

Hi there,

Terraform Version

$ terraform -v
Terraform v0.7.4

Affected Resource(s)

Please list the resources as a list, for example:

• aws_autoscaling_group

Terraform Configuration Files

This is an ASG defined in a module with some default tags:

resource "aws_autoscaling_group" "asg" {
  name = "${var.env}-${var.cell}-${var.app}"
  launch_configuration = "${aws_launch_configuration.lc.name}"
  .
  .
  .
  tag {
    key = "Name"
    value = "${var.env}-${var.app}"
    propagate_at_launch = true
  }

  tag {
    key = "app"
    value = "${var.env}-${var.app}"
    propagate_at_launch = true
  }
.
.
.

Info

I'd like to be able to pass this module some extra tags to add to the ASG. for example if I have a couple of different stacks using this module and they both require these default tags but then one of them requires some additional tags. Is this available already? I've done a fair amount of googling on this but cannot find anything on it.

It seems that because each tag is added individually rather than a list of tags that I can't add to the list. Is there a workaround for this or can we get it implemented?

Thanks,
Ryan

[mcinteer]

Been thinking a little more about this this evening and looking at the way the autoscaling group is implemented in TF I think that it would be very difficult to add in extensible tags like I want. Would a potential solution be to create a new resource type call something like aws_autoscaling_tag which could take in the name of the scaling group, the key and value of the tag. Then apply the tag to the existing group?

[mcinteer]

I have been playing around with the overrides feature built in to terraform to try and achieve this. But it would appear that I cannot override a resource in a module from the root, is this correct?

[morkot]

+1
I think this should be implemented and standardized as in aws_instance resource.

[morkot]

So, let's compare ASG and single EC2 instance tag description in terraform:

ASG:

resource "aws_autoscaling_group" "bar" {
...
  tag {
    key = "foo"
    value = "bar"
    propagate_at_launch = true
  }
  tag {
    key = "lorem"
    value = "ipsum"
    propagate_at_launch = false
  }
}

EC2 Instance:

resource "aws_instance" "bar" {
...
    tags = {
        Name = "HelloWorld"
        foo     = "bar"
    }

It would be great to have standard description of tags, smth like

ASG:

resource "aws_autoscaling_group" "bar" {
...
    tags = {
      Name = {
        value = "my-name"
        propagate_at_launch = true
      },
      MySecondTag = {
        value = "tag2"
        propagate_at_launch = false
      }
    }
}

In this way tags for ASG can be described in variables.tf and overridden later when module reused.

[morkot]

Or even simpler:
split those two tags to two different arguments, like:

resource "aws_autoscaling_group" "bar" {
...
    tags_propagated = {
      Name = "my-name"
      AnotherTagForInstances = "foo"
    }

    tags = {
      MyTagForASGNotPropagted = "baz"
    }
}

[morkot]

@mitchellh , could you take a look on this (above)

[jordiclariana]

It would be awesome to have this. Is there any plans to implement it?

[dene14]

Seriously... is it going to be implemented? Lack of this functionality affects flexibility in writing modules in a hard way

[CarlInglisBJSS]

Is there any news on this? Being able to set tags in the same way as other resources would be a great help for us.

[pgroudas]

I think this will issue will resolve it, which is slated for the next release: https://github.com/hashicorp/terraform/pull/13574/

[ashb]

That issue is good, but I can't think of any way with interpolations to let a module accept a map of tags (to set on VPC/segurity groups say) and to also apply those to ASG-created instances.

i.e. Is it possible to go from {"x": "y", "z": "w"} to [{"Key": "x", "Value": "y", "PropagateAtLaunch": true},{"Key": "z", "Value": "w", "PropagateAtLaunch": true}] using just pure HCL/interpolations?

[carlosonunez]

I had to write a script to get around this. Feel free to use it here: https://github.com/carlosonunez/terraform_asg_tag_creator

[hashibot[bot]]

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