def remove_snapshots_handler(event, context):
"""The entry point for the execution.
Starts the process of removing expired snapshots of volumes.
Can be triggered by different events in AWS.
:param event: event data
:type event: usually of the Python dict type.
It can also be list, str, int, float, or NoneType type.
:param context: AWS Lambda service uses this parameter to provide runtime information to the handler
:type context: LambdaContext
:return: None
"""
ec2 = boto3.resource('ec2', region_name='eu-west-1')
today = datetime.datetime.now().date()
filters = [{'Name': 'tag-key', 'Values': ['auto:snapshots:expiration_date']}]
snapshots = list(ec2.snapshots.filter(Filters=filters))
print("{} Snapshots exist".format(len(snapshots)))
for snapshot in snapshots:
tags = convert_tags_list_to_dict(snapshot.tags)
expiration_date = dateutil.parser.parse(tags['auto:snapshots:expiration_date']).date()
if expiration_date <= today:
print("Deleting snapshot {}, id: {}, expiration_date: {}".
format(tags['Name'], snapshot.snapshot_id, expiration_date))
snapshot.delete()
def create_snapshot(volume, service_resource):
"""
:param volume: the volume to backup
:type volume: ec2.Volume object
:param service_resource: the volume's resource
:type service_resource: ec2.ServiceResource object
:return:
"""
volume_tags = convert_tags_list_to_dict(volume.tags)
volume_id = volume.volume_id
volume_name = volume_tags.get('Name', '--no-name-specified--')
topic = volume_tags.get('auto:snapshot:topic')
retention_days = int(volume_tags.get('auto:snapshots:retention_days', settings.MAX_RETENTION_DAYS))
now = datetime.datetime.now()
expiration_date = (now + datetime.timedelta(days=retention_days)).date().isoformat()
current_snapshot_description = get_current_snapshot(volume_id)
version = get_next_version(current_snapshot_description)
snapshot_tags = {
'Name': "{}:{}".format(volume_name, str(version)),
'auto:snapshots:expiration_date': expiration_date,
'auto:snapshots:version': str(version),
"auto:snapshots:current:{}".format(volume_id): 'true'
}
print("Creating a snapshot backup of volume: {} id: {} at: {}".
format(volume_name, volume_id, now.isoformat()))
created_snapshot = service_resource.create_snapshot(
VolumeId=volume.volume_id,
Description="auto-snapshot backup of volumeId {} at {}".format(volume_id, now.isoformat()))
if not created_snapshot.meta.data['ResponseMetadata']['HTTPStatusCode'] == 200:
raise Exception("auto-snapshot error: HTTPStatusCode {}".
format(created_snapshot.meta.data['ResponseMetadata']['HTTPStatusCode']))
# add the tags for the new snapshot
service_resource.create_tags(
Resources=(created_snapshot.snapshot_id,),
Tags=convert_tags_dict_to_list(snapshot_tags)
)
# update the tags for the previous snapshot
if current_snapshot_description:
current_flag_tag = service_resource.Tag(
current_snapshot_description['SnapshotId'],
"auto:snapshots:current:{}".format(volume_id),
'true')
current_flag_tag.delete()
if topic:
notify(topic)
print("A snapshot backup of volume: {} is being created with id: {}, tags: {}".
format(volume_name, created_snapshot.snapshot_id, snapshot_tags))
def get_next_version(current_snapshot_description):
"""Get the version for the next snapshot backup
:param current_snapshot_description: A dict with the key: 'Tags'
The value of the key is a list of tags including the version e.g:
{'Tags': [{'Key': 'auto:snapshots:version', 'Value': '1'}]}
:type current_snapshot_description: dict or None
:return: The version number of the next snapshot
"""
if not current_snapshot_description:
current_version = 0
else:
current_snapshot_tags = convert_tags_list_to_dict(current_snapshot_description['Tags'])
current_version = int(current_snapshot_tags['auto:snapshots:version'])
current_version += 1
return current_version
