compile.json

{ 
  "variables": {
    "aws_access_key": "{{env `AWS_ACCESS_KEY_ID`}}",
    "aws_secret_key": "{{env `AWS_SECRET_KEY`}}",
    "artifact_token": "{{env `ARTIFACT_TOKEN`}}",
    "private_key": "{{env `AWS_SSH_KEY`}}"
  },
  "builders": [
    {
      "type": "amazon-ebs",
      "access_key": "{{user `aws_access_key`}}",
      "secret_key": "{{user `aws_secret_key`}}",
      "region": "us-west-2",
      "source_ami": "ami-5189a661",
      "instance_type": "t2.micro",
      "ssh_username": "ubuntu",
      "ssh_keypair_name": "vagrant",
      "ssh_private_key_file": "{{user `private_key`}}",
      "ami_name": "packer2 {{timestamp}}"
    }
  ],
  "post-processors": [
    {
      "type": "atlas",
      "token": "{{user `artifact_token`}}",
      "artifact": "kyawthetsein/packer2",
      "artifact_type": "amazon.ami",
      "metadata": {
          "created_at": "{{timestamp}}"
        }
    }
  ]
  
}