PACKER_LOG=1 /usr/local/bin/packer build /tmp/config.json

2018/10/20 22:17:14 [INFO] Packer version: 1.3.1
2018/10/20 22:17:14 Packer Target OS/Arch: linux amd64
2018/10/20 22:17:14 Built with Go Version: go1.11
2018/10/20 22:17:14 Detected home directory from env var: /root
Failed to parse template: Error parsing JSON: unexpected end of JSON input
At line 1, column 0 (offset 0):
    1:
     ^

Json :

{
  "builders": [{
      "type": "qemu",
      "iso_url": "/vp-image-iso/debian_base.iso",
      "iso_checksum": "XXXXXX",
      "ssh_username": "root",
      "ssh_password": "password",
      "iso_checksum_type": "md5",
      "output_directory": "mariadb_image",
      "headless": true,
      "vm_name": "mariadb"
    }],
  "provisioners": [{
      "type": "shell",
      "inline": "/tmp/install_ansible.sh"
    },
    {
      "type": "ansible-local",
      "playbook_file": "/tmp/ansible/local.yml"
    }]
}