main.tf

variable "do_api_token" {}

variable "vpn_instance_name" {
  description = "Instance name to use"
  default = ""
}

variable "region" {
  description = "An identifier of DigitalOcean region to put VPN/proxy instance to"
  default = "nyc2"
}

# VPN credentials

resource "random_string" "vpn_user" {
  length = 6
  special = false
}

resource "random_string" "vpn_password" {
  length = 8
  special = false
}

resource "random_string" "vpn_psk" {
  length = 8
  special = false
}

# SOCKS5 credentials

resource "random_string" "socks_user" {
  length = 6
  special = false
}

resource "random_string" "socks_password" {
  length = 8
  special = false
}

# Set up DigitalOcean instance running VPN and SOCKS5 proxy servers

provider "digitalocean" {
  token = "${var.do_api_token}"
}

resource "random_id" "vpn_instance_name" {
  prefix = "vpn-"
  byte_length = 4
}

resource "tls_private_key" "vpn" {
  algorithm = "RSA"
  rsa_bits  = "4096"
}

resource "digitalocean_ssh_key" "vpn" {
  name       = "VPN server"
  public_key = "${tls_private_key.vpn.public_key_openssh}"
}

resource "digitalocean_droplet" "vpn" {
  image  = "ubuntu-18-04-x64"
  name   = "${var.vpn_instance_name != "" ? var.vpn_instance_name : random_id.vpn_instance_name.hex}"
  size   = "s-1vcpu-1gb"
  region = "${var.region}"

  ssh_keys = ["${digitalocean_ssh_key.vpn.fingerprint}"]

  connection {
    type = "ssh"
    user = "root"
    private_key = "${tls_private_key.vpn.private_key_pem}"
    timeout = "2m"
  }

  provisioner "remote-exec" {
    inline = <<-EOF
      # install Docker CE according to https://www.digitalocean.com/community/tutorials/how-to-install-and-use-docker-on-ubuntu-18-04
      apt update
      apt -y install apt-transport-https ca-certificates curl software-properties-common
      curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
      add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable"
      apt update
      apt install -y docker-ce

      # install l2tp VPN server
      docker run -d --cap-add=NET_ADMIN -p 500:500/udp -p 4500:4500/udp -p 1701:1701/udp -p 1701:1701/tcp --restart=unless-stopped -e PSK=${random_string.vpn_psk.result} -e USERS=${random_string.vpn_user.result}:${random_string.vpn_password.result} siomiz/softethervpn:alpine

      # install socks5 proxy
      docker run -d --restart=unless-stopped -p 1080:1080 -e PORT=1080 -e USER=${random_string.socks_user.result} -e PASS=${random_string.socks_password.result} schors/tgdante2:latest
    EOF
  }
}