Baking AMIs in Spinnaker Pipeline using Chef-Solo - amazon-ec2

Question

I'm trying to build a test pipeline in Spinnaker to bake an AMI and then update a CloudFormation template to deploy the AMI to EC2 instances in an auto scaling group.
I have a small test Chef cookbook developed which works great when running packer locally. I am running berks local on my laptop to vendor my cookbooks and pull them from our internal Chef supermarket. Packer is configured with the chef-solo provisioner as shown in the sample packer template below, and will transfer the cookbooks to the packer builder EC2 instance and run Chef. Right now, we're testing with Linux but want to support both Linux and Windows AMIs.
Is it possible to use chef-solo with a custom packer template with Spinnaker? If so, when and where should berks run to vendor the cookbooks before packer executes?
{
"variables": {
"aws_access_key": "{{env `AWS_ACCESS_KEY_ID`}}",
"aws_secret_key": "{{env `AWS_SECRET_ACCESS_KEY`}}",
"aws_region": "{{env `AWS_REGION`}}",
"ssh_private_key_file": "{{env `SSH_PRIVATE_KEY_FILE`}}",
"subnet_id": "{{env `AWS_SUBNET_ID`}}",
"vpc_id": "{{env `AWS_DEFAULT_VPC_ID`}}"
},
"builders": [
{
"type": "amazon-ebs",
"access_key": "{{user `aws_access_key`}}",
"secret_key": "{{user `aws_secret_key`}}",
"region": "{{user `aws_region`}}",
"source_ami_filter": {
"filters": {
"virtualization-type": "hvm",
"name": "amzn2-ami-hvm-*-x86_64-gp2",
"root-device-type": "ebs"
},
"most_recent": true,
"owners": [
"amazon"
]
},
"ami_name": "test-ami-{{timestamp}}",
"ami_description": "Test Linux AMI",
"communicator": "ssh",
"instance_type": "m4.large",
"subnet_id": "{{user `subnet_id`}}",
"tags": {
"Name": "Test Linux AMI"
},
"ssh_username": "ec2-user",
"ssh_keypair_name": "TestKeypair",
"ssh_private_key_file": "{{user `ssh_private_key_file`}}",
"vpc_id": "{{user `vpc_id`}}"
}
],
"provisioners": [
{
"type": "shell-local",
"command": "berks vendor --delete -b ./Berksfile ./cookbooks"
},
{
"type": "chef-solo",
"cookbook_paths": [
"./cookbooks"
],
"run_list": [
"recipe[test_cookbook]"
]
}
}