Add RDP support to Ubuntu desktop image

ubuntu/focal_desktop/variables.auto.pkrvars.hcl

@@ -2,5 +2,6 @@ docker_repo               = "ghcr.io/utrechtuniversity/src-test-workspace:ubuntu
 img_tag                   = "ubuntu_focal-desktop"
 docker_base_img           = "ubuntu:focal"
 vagrant_base_img          = "ubuntu/focal64"
-extra_packages            = "xfce4"
+extra_packages            = "gdm3 xfce4 xrdp xauth xorgxrdp"
+extra_post_commands       = "update-alternatives --set x-session-manager /usr/bin/xfce4-session"
 workspace_ansible_version = "2.9"

ubuntu/src-ubuntu.pkr.hcl

@@ -66,6 +66,11 @@ variable "extra_packages" {
   type    = string
 }
 
+variable "extra_post_commands" {
+  default = ""
+  type    = string
+}
+
 variable "testuser" {
   type = map(string)
   default = {
@@ -191,7 +196,8 @@ build {
     inline = [
       "useradd -m -s $(which bash) -p $(openssl passwd -1  ${var.testuser.password}) ${var.testuser.username}",
       "apt-get autoremove -y -o APT::Autoremove::RecommendsImportant=0 -o APT::Autoremove::SuggestsImportant=0 && apt-get autoclean -y && apt-get clean -y", "rm -rf /tmp/* /var/tmp* /usr/share/doc/* /root/.ansible* /usr/share/man/* /root/.cache /etc/rsc/plugins/*",
-      "mkdir -p /usr/share/man/man1" # The step aboved removed all the man pages content, but this directory needs to be present as an install target for subsequent apt installs by components.
+      "mkdir -p /usr/share/man/man1", # The step above removed all the man pages content, but this directory needs to be present as an install target for subsequent apt installs by components.
+      var.extra_post_commands
     ]
   }