README.md

Finding Packer-generated AMIs automatically after builds

The basic technique is to have Packer add a tag with a unique value during the build, and use AWS' built-in filtering capabilities to find that specific AMI after the build finishes.

• template.json - Shows the settings that need to be added to your template
• build.sh - Shows how to use the template to do a build and retrieve the AMI information

build.sh

#!/bin/bash
# Generate a unique identified for this build. UUID is the easiest
UUID=$(uuid -v4)

# Pass the unique identifier to packer as a user variable
packer build -var build_uuid=${UUID} template.json

# Use the AWS CLI tools to query for AMIs, using the unique tag value to
# filter for the build we just did
aws ec2 describe-images --filters Name=tag:BuildUUID,Values=${UUID} > build.json

# Assuming you have `jq` installed (and you should if you're dealing with JSON)
AMI_ID=$(jq --raw-output '.Images[0].ImageId' build.json)

template.json

{
  "variables": {
    "build_uuid": null
  },
  "builders": [
    {
      "type": "amazon-ebs",
      "tags": {
        "BuildUUID": "{{user `build_uuid`}}"
      }
    }
  ]
}