How to pass docker swarm join-token using Terraform

When using terraform to create a swarm on DigitalOcean, how can I pass the join-token to a worker node? I can create a simple 2-node swarm; a manager node and a worker node; but there does not seem to be an efficient way to pass the join-token to the worker node:

*Code snippet manager node*
provisioner "remote-exec" {
     inline = [
      "sudo ufw allow 2377,7946/tcp",
      "sudo ufw allow 4789,7946/udp",
      "sudo docker swarm init --advertise-addr ${digitalocean_droplet.manager1.ipv4_address_private}"
      ]
  }

*Code snippet worker node*
    provisioner "remote-exec" {
     inline = [
      "sudo ufw allow 2377,7946/tcp",
      "sudo ufw allow 4789,7946/udp",
      "docker swarm join --token ${var.worker_token} ${digitalocean_droplet.manager1.ipv4_address_private}:2377"
      ]
  }

If I issue this command: docker swarm join-token -q worker I can display the token, but cannot save it to the variable ${var.worker_token} Example: “docker swarm join-token worker -q > ${var.worker_token}”

Does anyone have some insight on how to assign the output of a command to a variable and reference it later in the terraform plan?

Thank you