1#!/usr/bin/env python3
2"""
3Get the checksum/hash of an object in S3.
4"""
5
6import argparse
7import hashlib
8import os
9
10import tqdm
11
12from _common import create_s3_session, parse_s3_uri
13
14
15def parse_args():
16    parser = argparse.ArgumentParser(
17        prog=os.path.basename(__file__), description="Get the hash of an object in S3"
18    )
19
20    parser.add_argument("S3_URI")
21    parser.add_argument(
22        "--algorithm", help="which checksum algorithm to use", default="sha256"
23    )
24
25    return parser.parse_args()
26
27
28if __name__ == "__main__":
29    args = parse_args()
30
31    s3_location = parse_s3_uri(args.S3_URI)
32
33    sess = create_s3_session(args.S3_URI)
34
35    s3_obj = sess.client("s3").get_object(
36        Bucket=s3_location["Bucket"], Key=s3_location["Path"]
37    )
38
39    h = hashlib.new(args.algorithm)
40
41    with tqdm.tqdm(total=s3_obj["ContentLength"], unit="B", unit_scale=True) as pbar:
42        while True:
43            chunk = s3_obj["Body"].read(8192)
44            pbar.update(len(chunk))
45            h.update(chunk)
46
47            if not chunk:
48                break
49
50    print(h.hexdigest(), end="")