Question

DigitalOcean Terraform can't work with Count and droplet_ids

When trying to run the following script I get an error and I don’t understand why. All the example show it should be done this way:

resource "digitalocean_loadbalancer" "web" {
  name   = "loadbalancer-1"
  region = "ams3"

  forwarding_rule {
    entry_port     = 80
    entry_protocol = "http"

    target_port     = 80
    target_protocol = "http"
  }

  healthcheck {
    port     = 80
    protocol = "tcp"
  }

  droplet_ids = ["${digitalocean_droplet.web.*.id}"]
}

resource "digitalocean_droplet" "web" {
  count              = 2
  image              = "ubuntu-18-04-x64"
  name               = "web-${count.index + 1}"
  region             = "ams3"
  size               = "s-1vcpu-1gb"
  private_networking = true
  user_data          = "${file("config/webuserdata.sh")}"
  ssh_keys = [
    "${var.ssh_fingerprint}"
  ]
}

The error:

Error: Incorrect attribute value type

  on web.tf line 18, in resource "digitalocean_loadbalancer" "web":
  18:   droplet_ids = ["${digitalocean_droplet.web.*.id}"]

Inappropriate value for attribute "droplet_ids": element 0: number required.

I’m new to terraform and I don’t know how to solve this issue.


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Accepted Answer

Terraform recently released a major new version, 0.12.x. This included some fairly important changes in syntax. One of these changes is “first-class list support.” Check out that link for all the details. But to solve your immediate problem, just change:

droplet_ids = ["${digitalocean_droplet.web.*.id}"]

to:

droplet_ids = digitalocean_droplet.web.*.id

Since some of the changes to the syntax were disruptive, Terraform 0.12 comes with an upgrade command that can make these changes for you automatically. Running the following should resolve the issue:

terraform 0.12upgrade

I’d recommend running after first checking your existing work into a git branch so that you can review the changes it makes by looking at the diff.

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