Gets the history of a specific file in all the commits of a repository

get_file_history.py

"""
get_file_history.py
Gets the history of a specific file in all the commits of a repo.

GitPython: https://gitpython.readthedocs.io/en/stable/index.html
"""

# ==============================================================================

import json
from pathlib import Path

import git

# ==============================================================================

# Path to the repository folder.
REPO_PATH = '.'
# The file paths to filter by. Only return commits that change any of
# these paths. If empty, returns all commits.
FILE_PATHS = [
    'data/',
]
# The number of commits to process. Set to None to process all commits.
NUM_COMMITS = None

DATETIME_FMT = '%Y-%m-%d %H:%M:%S'

# ==============================================================================

PROCESSED_COMMITS = Path('processed_commits.json')

# ==============================================================================


def process_file(commit_sha, commit_datetime, filename, file_contents):
    """Do something with the file, such as save it.
    This function will be called for every file in every commit, even if it's
    not in `FILE_PATHS`. If needed, filter it out before processing the file.
    """


# ==============================================================================


def main():
    processed_commits = json.loads(
        PROCESSED_COMMITS.read_text(encoding='utf-8'))

    repo = git.Repo(REPO_PATH)

    try:
        count = 0
        for commit in repo.iter_commits(paths=FILE_PATHS):
            commit_sha = commit.hexsha
            if commit_sha in processed_commits:
                # do not re-process this commit
                continue
            commit_datetime = commit.committed_datetime
            commit_files = []
            for file in commit.stats.files:
                if ' => ' in file:
                    # renamed file
                    left, right = file.split(' => ')
                    if '{' in file and '}' in file:
                        # only a part was renamed
                        # remove the '{'
                        unchanged_left, old_name = left.split('{')
                        # remove the '}'
                        new_name, unchanged_right = right.split('}')
                        new_file = unchanged_left + new_name + unchanged_right
                    else:
                        # the entire file was renamed
                        new_file = right
                    file = new_file
                try:
                    file_data = commit.tree / file
                except KeyError:
                    # file was deleted (probably)
                    continue
                commit_files.append(file)
                file_contents = file_data.data_stream.read()
                process_file(commit_sha, commit_datetime, file, file_contents)
            processed_commits[commit_sha] = {
                'author': commit.author.name,
                'email': commit.author.email,
                'datetime': commit_datetime.strftime(DATETIME_FMT),
                'message': commit.message,
                'files': commit_files,
            }
            count += 1
            if NUM_COMMITS is not None and count >= NUM_COMMITS:
                break
    finally:
        PROCESSED_COMMITS.write_text(json.dumps(processed_commits, indent=2),
                                     encoding='utf-8')


if __name__ == '__main__':
    main()

Note: If using a local git repository (as I am), you must git pull before running to get updated commit data.