Snapshot the volume mounted at specified mount point in AWS, delete old snapshots

snaphot_volume.py

#! /usr/bin/python

from boto.utils import get_instance_metadata
import boto.ec2
import argparse, logging, datetime

def parsed_args():
  # parse cmd line args
  parser = argparse.ArgumentParser(description='Snapshot the volume mounted at specified mount point in AWS, delete old snapshots.')
  parser.add_argument('--tag-name',
                      help='Name of tag to apply to snapshot')
  parser.add_argument('--tag-value',
                      help='Value of tag to apply to snapshot')
  parser.add_argument('--mount-point',
                      help='The mount point as defined by AWS to look for the volume. default is /dev/sdf',
                      default='/dev/sdf')
  parser.add_argument('--retention',
                      help='Retention period (days) to keep snapshots for, older snapshots will be deleted. default is 31 days',
                      default='31')
  return parser.parse_args();

def main():
  args = parsed_args();

  volume = find_volume(args.mount_point)
  create_snapshot(volume, args.tag_name, args.tag_value)
  delete_snapshots(volume, int(args.retention))

  exit(0)

def find_volume(mount_point):
  logging.info('Finding volume...')

  conn = boto.ec2.connect_to_region(current_region())
  metadata = get_instance_metadata()
  vols = conn.get_all_volumes(filters={'attachment.instance-id':metadata['instance-id']})

  matches = [x for x in vols if x.attach_data.device == mount_point]

  if(len(matches) == 1):
    return matches[0]
  else:
    raise Exception('No attached volume could be found for %s' % mount_point)

def create_snapshot(volume, tagName, tagValue):
  logging.info('Creating snapshot...')

  snap = volume.create_snapshot('Orchestra snapshot for stack %s' % tagValue)
  snap.add_tag(tagName, tagValue)

  logging.info('Snapshot created!')

def delete_snapshots(volume, days):
  d = datetime.date.today() + datetime.timedelta(days=-days)

  logging.info('deleting snapshots older than %s...' % d)

  for snap in volume.snapshots():
    start_time = datetime.datetime.strptime(snap.start_time, '%Y-%m-%dT%H:%M:%S.%fZ')
    
    if start_time.date() < d:
      logging.info('deleting snapshot %s with start_time %s' % (snap.id, start_time))
      snap.delete()

def current_zone():
  metadata = get_instance_metadata()
  return metadata['placement']['availability-zone']

def current_region():
  zone = current_zone()
  return zone[:-1]

if __name__ == '__main__':
  logging.getLogger().setLevel(logging.INFO)
  main()