{
    "variables": {
        "account_file": null,
        "project_id": null
    },

    "builders": [{
        "type": "googlecompute",
        "account_file": "{{user `account_file`}}",
        "project_id": "{{user `project_id`}}",

        "image_name": "packerbats-minimal-{{timestamp}}",
        "source_image": "debian-7-wheezy-v20141108",
        "zone": "us-central1-a"
    }]
}