Amazon AWS EC2 Snapshot Creation Lambda

gistfile1.txt

import boto3
import collections
import datetime

ec = boto3.client('ec2')

# inspired by https://serverlesscode.com/post/lambda-schedule-ebs-snapshot-backups/
#
# snapshot creation lambda
#   this function creates snapshots
#   prerequisites:
#     only attached volumes are considered
#     the instance that owns the volume must have a Backup=true tag
#     individual volumes will be skipped if they have a Backup=false tag

def lambda_handler(event, context):
    reservations = ec.describe_instances()['Reservations']
    
    for reservation in reservations:
        for instance in reservation['Instances']:
            backup = False

            for tag in instance['Tags']:
                key = tag['Key']
                value = tag['Value']
                
                if key == 'Backup':
                    backup = tag['Value'] == 'true'
                    break

            if not backup: continue

            for device in instance['BlockDeviceMappings']:
                if device.get('Ebs', None) is None: continue
                
                volumeId = device['Ebs']['VolumeId']
                
                info = ec.describe_volumes(VolumeIds=[volumeId])['Volumes'][0]
                name = volumeId
                skip = False
                
                for tag in info['Tags']:
                    key = tag['Key']
                    
                    if key == 'Backup':
                        skip = tag['Value'] == 'false'
                    elif key == 'Name':
                        name += ' (' + tag['Value'] + ')'

                if skip:
                    print 'Snapshot of volume %s skipped due to presence of Backup=false tag' % (name)
                    continue

                print 'Snapshot of volume %s created' % (name)
                
                snapshot = ec.create_snapshot(VolumeId=volumeId)
                snapshotId = snapshot['SnapshotId']
                
                tags = [
                    {'Key': 'createdByEBSSnapshotter', 'Value': 'true'},
                    {'Key': 'Name', 'Value': name}
                ]
                
                ec.create_tags(Resources=[snapshotId], Tags=tags)