Warns users if staged files are larger than some limit

pre-commit-filesize.py

#!/usr/bin/python3
"""
Checks file size of committed files. If there are stage files bigger than a
given size (`WARN_SIZE_MB`) then
    * the commit is aborted
    * you are told about the offending files
    * you are told the command for forcing through the commit anyway

Save this file as "pre-commit" in your .git/hooks folder and do

    $ chmod a+x pre-commit

You can change the file warning size limit by updating `WARN_SIZE_MB`.
"""

import os
import subprocess
import sys

# --------------------------------------
# Update to change the warning threshold
# --------------------------------------
WARN_SIZE_MB = 5
# --------------------------------------

# -----------------------------
# Do not change below this line
# -----------------------------
MAX_STR_LEN = 25

# Terminal colour codes
ENDC = '\033[0m'
BOLD = '\033[1m'
OKGREEN = '\033[92m'
WARNING = '\033[93m'
FAIL = '\033[91m'


def main():

    git = subprocess.Popen(
        ['git', 'diff', '--cached', '--name-only', '--diff-filter=AM'],
        stdout=subprocess.PIPE)
    staged_files = git.stdout.read().decode("utf-8").strip().splitlines()

    # Look at the size of all the staged files
    big_files = []
    ok_files = []
    warn_size_bytes = WARN_SIZE_MB * 1000 * 1000
    for file in staged_files:
        size_in_bytes = os.path.getsize(file)
        
        if len(file) > MAX_STR_LEN:  # clean names for stdout
            file = file[:MAX_STR_LEN - 3] + "..."
        else:
            file = file.ljust(MAX_STR_LEN)
            
        if size_in_bytes >= warn_size_bytes:
            big_files.append((file, size_in_bytes / 1000000))
        else:
            ok_files.append((file, size_in_bytes / 1000))

    if big_files:
        commit_aborted = FAIL + BOLD + ">" * 18 + " COMMIT ABORTED " + "<" * 18 + ENDC
        print(commit_aborted)
        print("The following files exceed the file size limit ({}MB):".format(
            WARN_SIZE_MB))
        for file, size in big_files:
            print("\t" + file + FAIL + "\t{:0.2f}MB".format(size) + ENDC)
        print("\nThe following files are OK:")
        for file, size in ok_files:
            print("\t" + file + OKGREEN + "\t{:0.2f}KB".format(size) + ENDC)
        print(
            "\nIf you still want to commit all these files please use the following command:"
        )
        print(WARNING + "\tgit commit --no-verify\n" + ENDC)
        print(commit_aborted)
        sys.exit(1)

    sys.exit(0)


if __name__ == '__main__':
    main()