checked used -vs- reserved instances in ec2

reservations.rb

#!/usr/bin/ruby
# reports used -vs- reserved instances in ec2
#
# needs `{apt-get,brew} install awscli` with an `AWS_PROFILE` configured
require 'json'

def reserved_instances
  JSON(`aws --profile=#{AWS_PROFILE} ec2 describe-reserved-instances`)["ReservedInstances"]
end

def active_reserved_instances
  reserved_instances.select{ |instance| instance["State"] == "active" }
end

def active_reserved_instance_types
  instance_types = Hash.new(0)
  active_reserved_instances.each do |instance|
    az = instance["AvailabilityZone"]
    type = instance["InstanceType"]
    count = instance["InstanceCount"]

    unless instance_types.has_key?(az) then
      instance_types[az] = Hash.new(0)
    end
    instance_types[az][type] += count
  end
  instance_types
end

def current_reservations
  JSON(`aws --profile=#{AWS_PROFILE} ec2 describe-instances`)["Reservations"]
end

def current_instance_types
  instance_types = Hash.new(0)
  current_reservations.each do |reservation|
    reservation["Instances"].each do |instance|
      pg = instance["Placement"]
      az = pg["AvailabilityZone"]
      #az = instance["Placement"]["AvailabilityZone"]
      type = instance["InstanceType"]

      unless instance_types.has_key?(az) then
        instance_types[az] = Hash.new(0)
      end
      instance_types[az][type] += 1
    end
  end
  instance_types
end

def sorted(hash)
  Hash[hash.sort_by(&:first)]
end

%w(us-west-2a us-west-2b us-west-2c).each do |az|
  puts "for az #{az}:"
  puts "reserved: #{sorted(active_reserved_instance_types[az])}"
  puts "    used: #{sorted(current_instance_types[az])}"
  puts
end