ec2 snapshot script, max snaps sets revolving snapshots to expire when rerun; expects volume to have tag: snapshot, some-unique-name

ec2-snapshots.py

import boto.ec2
import sys

def get_snaps (desc, vol,conn):
    snapshots =  conn.get_all_snapshots(owner='id...',
                                        filters={'description':'*'+desc+'*'})
    return snapshots


def op_snaps (vols,max_snaps,conn):
    for v in iter(vols):
        print ("\n",v, ":", vols[v])
        snapshots = get_snaps(v,vols[v],conn)

        ## they come sorted, but sort anyway
        snapshots = sorted(snapshots,key=lambda snap:snap.start_time)
        done_snaps = list(filter(lambda snap:snap.status == 'completed',snapshots))
        
        ## create new snaps, only if there are none in progress!
        if len(snapshots) <= len(done_snaps):
            snap = conn.create_snapshot(vols[v], v)
            print ("creating:",v,snap)

        ## delete snaps, if completed snaps is more than max
        if len(done_snaps) >= max_snaps:
            print("removing snaps:",len(snapshots) - (max_snaps-1))
            for n in range(len(snapshots) - (max_snaps-1)):
                print ("deleting:",v,snapshots[n].id)
                conn.delete_snapshot(snapshots[n].id)



def start_snaps (tag):
    snap_tag = str(tag)

    max_snaps = 2
    conn = boto.ec2.connect_to_region("us-east-1",
                                      aws_access_key_id='id...',
                                      aws_secret_access_key='key...')

    all_vols = conn.get_all_volumes(filters={"tag:snapshot":snap_tag+"*"})

    if len(all_vols) < 1: 
        print ("no volumes found with snapshot tag",snap_tag)
        return

    vols = dict()
    for n in all_vols:
        vols[n.tags['snapshot']] = n.id

    op_snaps(vols,max_snaps,conn)


def main (argv):
    if len(sys.argv) < 2: 
        print("snapshot tag required!")
        return

    start_snaps(sys.argv[1])


if __name__ == "__main__":
    main(sys.argv)

output

python ss.py dev


 dev iis : vol-d...
removing snaps: 1
deleting: dev iis Snapshot:snap-2...
creating: dev iis Snapshot:snap-5...

 dev root : vol-6...
removing snaps: 1
deleting: dev root Snapshot:snap-3...
creating: dev root Snapshot:snap-d...

 dev sql : vol-1...
removing snaps: 1
deleting: dev sql Snapshot:snap-9...
creating: dev sql Snapshot:snap-4...