Generate an S3 signed URL

gen_s3_url.py

#!/usr/bin/env python
# Tested with Python 3
# Needs boto3 installed (pip install --user boto3)
import optparse
import sys
import boto3


def sign(bucket, path, expiry):
    s3 = boto3.client('s3')

    return s3.generate_presigned_url(
        ClientMethod='get_object',
        Params={
          'Bucket': bucket,
          'Key': path,
        },
        ExpiresIn=int(expiry),
        HttpMethod='GET'
    )


if __name__ == '__main__':
    parser = optparse.OptionParser()
    parser.add_option('-b', '--bucket', dest='bucket', help='S3 bucket containing the file')
    parser.add_option('-p', '--path', dest='path', help='Path to the file (relative to the bucket)')
    parser.add_option('--expiry', dest='expiry', default='315360000', help='Expiry time, in seconds (defaults to ten years)')

    options, args = parser.parse_args()

    for opt in ('bucket', 'path'):
        assert options.__dict__.get(opt), '%s is not optional' % opt

    print(sign(
        bucket=options.bucket,
        path=options.path,
        expiry=options.expiry
    ))
    sys.exit(0)