clean_aws_cruft.rb

require 'aws-sdk'
require 'time'
require 'yaml'
require 'httparty'

Aws.config.update({region: 'us-east-1', credentials: Aws::Credentials.new('access_key', 'secret_key')})
ec2 = Aws::EC2::Client.new(region: 'us-east-1')

def get_amis(ec2)
  amis = ec2.describe_images({owners: ['self']}).images
  amis.sort{|a,b| Time.parse(a.creation_date) <=> Time.parse(b.creation_date)  }
end

def get_removables(ec2)

  snaps =  ec2.describe_snapshots({owner_ids: ['self']}).snapshots
  vols = ec2.describe_volumes.volumes
  amis = ec2.describe_images({owners: ['self']}).images


  # snapshot ids mentioned in amis
  ami_snaps = amis.map do |ami|
    ami.block_device_mappings.map do |bdm| 
      unless bdm.ebs.respond_to? :snapshot_id
        1
      else
        bdm.ebs.snapshot_id
      end
    end
  end

  ami_snaps =  ami_snaps.flatten.find_all{|i| i != 1}

  vol_snaps = vols.map{|i| i.snapshot_id}

  snap_ids = snaps.map{|i|i.snapshot_id}

  removeme = snap_ids - ami_snaps

  removeme = removeme - vol_snaps

  removeme

end

def get_bioc_amis
  yaml_str = HTTParty.get("http://master.bioconductor.org/config.yaml")
  yaml = YAML::load(yaml_str)
  yaml["ami_ids"].values
end

def rmami(ec2, ami_id)
  bioc_amis = get_bioc_amis()
  running_amis = get_running_amis(ec2)
  if bioc_amis.include? ami_id
    puts "#{ami_id} is in bioc_amis! Not deleting it."
    return
  end
  if running_amis.include? ami_id
    puts "#{ami_id} is in running_amis! Not deleting it."
    return
  end
  puts "deleting #{ami_id}"
  ec2.deregister_image({image_id: ami_id})
end

def rmsnap(ec2, snap_id)
  ec2.delete_snapshot({snapshot_id: snap_id})
end

def get_running_amis(ec2)
  instances = ec2.describe_instances
  instances.reservations.map{|i| i.instances.first.image_id}
end

# workflow:
# log in
# amis = get_amis ec2
# if one looks removable, try 
# rmami(ec2, amis[x].image_id) # where x is the candidate
# if that works, then wait a sec and do:
# get_removables(ec2) # returns removable snapshots
# ...review them and if all is ok
# ...and the one to remove is first in the array:
# rmsnap(ec2, get_removables(ec2).first)