prepare-commit-msg

#!/usr/bin/env python3
import re
import sys

from subprocess import check_output

commit_msg_filepath = sys.argv[1]

stdout_encoding = sys.stdout.encoding

branch = check_output(['git', 'symbolic-ref', '--short', 'HEAD']).strip()
branch = branch.decode(stdout_encoding)
branch = branch.strip()

# Skip special branches
if branch in ['master', 'dev', 'stage']:
    sys.exit(0)

branch_name_fragments = branch.split("_")

if len(branch_name_fragments) != 3:
    print('your branch name is incorrectly formatted')
    sys.exit(1)

ticket_type, ticket_message, ticket_number = branch.split("_")

with open(commit_msg_filepath, 'r+') as fh:

    commit_msg = fh.read()

    # check that our commit message doesn't already have a prefix
    if not re.match('^\[\w|#\d+', commit_msg):
        fh.seek(0, 0)
        fh.write("[{ticket_type}|#{ticket_number}] {commit_msg}".format(
            ticket_type=ticket_type,
            ticket_number=ticket_number,
            commit_msg=commit_msg
        ))