AWS EC2 standalone snapshot (not related AMI) check script

snapshot.py

# standalone AWS snapshot (no related AMI) check script
# AMIが存在しない自己所有スナップショットを発見＆削除するスクリプト

from __future__ import print_function
import boto3
import sys


def each_snapshots(client):
    next_token = ""
    while True:
        response = client.describe_snapshots(
                MaxResults=100,
                OwnerIds=["self"],
                NextToken=next_token,
        )
        if len(response["Snapshots"]) == 0 or "NextToken" not in response:
            break
        for snapshot in response["Snapshots"]:
            yield snapshot
        next_token = response["NextToken"]


def find_ami(client, snapshot_id):
    image = client.describe_images(
            Filters=[
                {
                    "Name": "block-device-mapping.snapshot-id",
                    "Values": [snapshot_id],
                    }
                ]
            )
    if len(image["Images"]) == 0:
        return False
    return image["Images"][0]


def delete_snapshot(ec2, snapshot_id):
    snapshot = ec2.Snapshot(snapshot_id)
    snapshot.delete()


if __name__ == "__main__":
    client = boto3.client("ec2")
    ec2 = boto3.resource("ec2")
    count = 0
    delete = len(sys.argv) > 1 and sys.argv[1] == "--delete"
    for snapshot in each_snapshots(client):
        snapshot_id = snapshot["SnapshotId"]
        ami = find_ami(client, snapshot_id)
        if not ami:
            print("snapshot ID {0} (created at {1:%Y-%m-%d}) is not found AMI.".format(snapshot["SnapshotId"], snapshot["StartTime"]))
            count += 1
            if delete:
                delete_snapshot(ec2, snapshot_id)
                print("deleted.")

    print("{} snapshots found.".format(count))