Determine the latest CoreOS AMI available

gistfile1.txt

#!/bin/sh

COREOS_CHANNEL=stable
BASE=http://$COREOS_CHANNEL.release.core-os.net/amd64-usr
AWS_REGION=eu-west-1
COREOS_VERSION=$(curl -s $BASE/current/version.txt | sed -n 's/COREOS_VERSION=//p')

parse_ami() {
	jq -r ".amis | map(select(.name == \"$AWS_REGION\")) | .[].hvm"
}

AMI=$(curl -s $BASE/$COREOS_VERSION/coreos_production_ami_all.json | parse_ami)

cat <<EOF
# Corresponds to CoreOS $COREOS_VERSION
ami: $AMI
EOF