require 'aws-sdk'
require 'date'
now = Date.today
days_ago_7 = now - 7
days_ago_30  = now - 30
years_ago_3 = now - ( 365 * 3 )

rds = Aws::RDS::Client.new(region: 'us-west-1')
config_array = { db_instance_identifier: "bn-mysql-read-1",}
snapshots = rds.describe_db_snapshots(config_array).db_snapshots

#protect all snapshots less than 7 days old
snapshots = snapshots.reject {|snapshot| snapshot['snapshot_create_time'].to_date > days_ago_7 }

#protect 1 snapshot a day that is older than 1 week but less than a month old
datehash = Hash.new
snapshots = snapshots.reject do |snapshot|
  if snapshot['snapshot_create_time'].to_date < days_ago_7
    if snapshot['snapshot_create_time'].to_date > days_ago_30 and datehash.has_key? snapshot['snapshot_create_time'].to_date.strftime("%x")
      false
    else
      datehash[snapshot['snapshot_create_time'].to_date.strftime("%x")] = 0
      true
    end
  else
    false
  end
end
#protect 1 snapshot a month that is older than 1 month but less than 3 years old
datehash = Hash.new
snapshots = snapshots.reject do |snapshot|
  if snapshot['snapshot_create_time'].to_date < days_ago_30
    if snapshot['snapshot_create_time'].to_date > years_ago_3 and
      datehash.has_key? snapshot['snapshot_create_time'].to_date.strftime("%y/%m")
      false
    else
      datehash[snapshot['snapshot_create_time'].to_date.strftime("%y/%m")] = 0
      true
    end
  else
    false
  end
end
p snapshots = snapshots.collect { |item| item['db_snapshot_identifier']}

snapshots.each do |snapshot|
  rds.delete_db_snapshot(
    {
      db_snapshot_identifier: snapshot, # required
  })
end