Show freeable space in a borg repository.

borg-show-free-space.py

"""
{[0]} path/to/hints.N

Show freeable space in a borg repository.

That is, amount of bytes accounted to deleted objects that have not been
compacted away yet.
"""

import sys

import msgpack

if len(sys.argv) != 2:
    print(__doc__.format(sys.argv).strip())
    sys.exit(0)

print("Pointed at hints file:", sys.argv[1])

with open(sys.argv[1], 'rb') as file:
    hints = msgpack.unpack(file)

assert hints[b'version'] == 2, "Need v2 hints file"

print("Freeable space:", sum(hints[b'compact'].values()), "bytes")