createsnapshot.py

import boto3  
import collections  
import datetime

#Please mention your region name
#below line code is call cross region
ec = boto3.client('ec2', region_name='us-east-1')
    
    #begins lambda function
def lambda_handler(event, context):  
        # mention your tag values below example "Backup-snap"
        reservations = ec.describe_instances(
            Filters=[
                {'Name': 'tag-key', 'Values': ['Backup', 'True']},
            ]
        ).get(
            'Reservations', []
        )
    
        instances = sum(
            [
                [i for i in r['Instances']]
                for r in reservations
            ], [])
    
        print "Number of the Instances : %d" % len(instances)
    
        to_tag = collections.defaultdict(list)
        
        for instance in instances:
            try:
                retention_days = [
                    int(t.get('Value')) for t in instance['Tags']
                    if t['Key'] == 'Retention'][0]
            except IndexError:
                # Please give your retention period day
                retention_days = 7
    
            for dev in instance['BlockDeviceMappings']:
                if dev.get('Ebs', None) is None:
                    continue
                vol_id = dev['Ebs']['VolumeId']
                for name in instance['Tags']:
                    # To store the instance tag value
                    Instancename= name['Value']
                    # To store the instance key value
                    key= name['Key']
                    # Below the code is create Snapshot name as instance Name 
                    if key == 'Name' :
                        ins_name = Instancename
                        print "Found EBS volume %s on instance %s" % (
                        vol_id, instance['InstanceId'])
    
                #To get all the instance tags deatils
                for name in instance['Tags']:
                    # To store the instance tag value
                    Instancename= name['Value']
                    # To store the instance key value
                    key= name['Key']
                    # Below the code is create Snapshot name as instance Name 
                    if key == 'Name' :
                        snap = ec.create_snapshot(
                        VolumeId=vol_id,
                        Description=Instancename,
                        )
                        print "snap %s" %snap
    
                to_tag[retention_days].append(snap['SnapshotId'])
    
                print "Retaining snapshot %s of volume %s from instance %s for %d days" % (
                    snap['SnapshotId'],
                    vol_id,
                    instance['InstanceId'],
                    retention_days,
    
                )
                for retention_days in to_tag.keys():
                    # if this runs on a Monday, then start doing weekly, monthly, or whatever....
                    if datetime.datetime.today().weekday() == 0:
                        # set retention to 4 weeks, and tag as Version: Weekly
                        delete_date = datetime.date.today() + datetime.timedelta(days=30)
                        print "Snapshot being marked as weekly. Will keep until %s" % str(delete_date)
                        version = 'Weekly'
                    else:
                        version = 'Daily'
                        delete_date = datetime.date.today() + datetime.timedelta(days=retention_days)
                        
                    snap = snap['Description'] + str('_')
                    # Here to get current date 
                    snapshot = snap + str(datetime.date.today())   
                    # to mention the current date formet
                    delete_fmt = delete_date.strftime('%Y-%m-%d')
                    print "Will delete %d snapshots on %s" % (len(to_tag[retention_days]), delete_fmt)
                    # below code is create the name and current date as instance name
                    ec.create_tags(
                    # this grabs the snapshot id from the list and applies the following tags
                    Resources=to_tag[retention_days],
                    Tags=[
                    {'Key': 'DeleteOn', 'Value': delete_fmt},
                    {'Key': 'Name', 'Value': snapshot },
                    {'Key': 'Version', 'Value': version},
                    ]
                    )
            to_tag.clear()