packer.json

{
  "min_packer_version": "1.10.0",
  "variables": {
    "distro_name": "{{env `DISTRO_NAME`}}",
    "distro_version": "{{env `DISTRO_VERSION`}}",
    "distro_codename": "{{env `DISTRO_CODENAME`}}",
    "output_dir": "/workspace/dist/{{user `distro_codename`}}",
    "source_dest": "/tmp/source"
  },
  "builders": [
    {
      "type": "docker",
      "image": "{{user `distro_name`}}:{{user `distro_version`}}",
      "privileged": true,
      "discard": true,
      "volumes": {  "{{pwd}}/": "/workspace"}
    }
  ],
  "provisioners": [
    {
      "type": "shell",
      "environment_vars": [
	"DEBIAN_FRONTEND=noninteractive",
        "DISTRO_NAME={{user `distro_name`}}",
        "UBUNTU_RELVER={{user `distro_version`}}",
        "UBUNTU_CODENAME={{user `distro_codename`}}",
        "OUTPUT_DIR={{user `output_dir`}}",
	"VENDOR='{{user `vendor`}}'"
      ],
      "scripts": [
        "scripts/setup.sh",
        "scripts/build.sh"
      ]
    }

  ]
}