Get the current git hash in a Python script

This post contains the command, Greg’s answer contains the subprocess command.

import subprocess

def get_git_revision_hash() -> str:
    return subprocess.check_output(['git', 'rev-parse', 'HEAD']).decode('ascii').strip()

def get_git_revision_short_hash() -> str:
    return subprocess.check_output(['git', 'rev-parse', '--short', 'HEAD']).decode('ascii').strip()

when running

print(get_git_revision_hash())
print(get_git_revision_short_hash())

you get output:

fd1cd173fc834f62fa7db3034efc5b8e0f3b43fe
fd1cd17

numpy has a nice looking multi-platform routine in its setup.py:

import os
import subprocess

# Return the git revision as a string
def git_version():
    def _minimal_ext_cmd(cmd):
        # construct minimal environment
        env = {}
        for k in ['SYSTEMROOT', 'PATH']:
            v = os.environ.get(k)
            if v is not None:
                env[k] = v
        # LANGUAGE is used on win32
        env['LANGUAGE'] = 'C'
        env['LANG'] = 'C'
        env['LC_ALL'] = 'C'
        out = subprocess.Popen(cmd, stdout = subprocess.PIPE, env=env).communicate()[0]
        return out

    try:
        out = _minimal_ext_cmd(['git', 'rev-parse', 'HEAD'])
        GIT_REVISION = out.strip().decode('ascii')
    except OSError:
        GIT_REVISION = "Unknown"

    return GIT_REVISION

No need to hack around getting data from the git command yourself. GitPython is a very nice way to do this and a lot of other git stuff. It even has "best effort" support for Windows.

After pip install gitpython you can do

import git
repo = git.Repo(search_parent_directories=True)
sha = repo.head.object.hexsha

Something to consider when using this library. The following is taken from gitpython.readthedocs.io

Leakage of System Resources

GitPython is not suited for long-running processes (like daemons) as it tends to leak system resources. It was written in a time where destructors (as implemented in the __del__ method) still ran deterministically.

In case you still want to use it in such a context, you will want to search the codebase for __del__ implementations and call these yourself when you see fit.

Another way assure proper cleanup of resources is to factor out GitPython into a separate process which can be dropped periodically

If subprocess isn’t portable and you don’t want to install a package to do something this simple you can also do this.

import pathlib

def get_git_revision(base_path):
    git_dir = pathlib.Path(base_path) / '.git'
    with (git_dir / 'HEAD').open('r') as head:
        ref = head.readline().split(' ')[-1].strip()

    with (git_dir / ref).open('r') as git_hash:
        return git_hash.readline().strip()

I’ve only tested this on my repos but it seems to work pretty consistantly.

Here’s a more complete version of Greg’s answer:

import subprocess
print(subprocess.check_output(["git", "describe", "--always"]).strip().decode())

Or, if the script is being called from outside the repo:

import subprocess, os
print(subprocess.check_output(["git", "describe", "--always"], cwd=os.path.dirname(os.path.abspath(__file__))).strip().decode())

Or, if the script is being called from outside the repo and you like pathlib:

import subprocess
from pathlib import Path
print(subprocess.check_output(["git", "describe", "--always"], cwd=Path(__file__).resolve().parent).strip().decode())

If you don’t have Git available for some reason, but you have the git repo (.git folder is found), you can fetch the commit hash from .git/fetch/heads/[branch].

For example, I’ve used a following quick-and-dirty Python snippet run at the repository root to get the commit id:

git_head = '.git\HEAD'

# Open .gitHEAD file:
with open(git_head, 'r') as git_head_file:
    # Contains e.g. ref: ref/heads/master if on "master"
    git_head_data = str(git_head_file.read())

# Open the correct file in .gitrefheads[branch]
git_head_ref = '.git\%s' % git_head_data.split(' ')[1].replace('/', '\').strip()

# Get the commit hash ([:7] used to get "--short")
with open(git_head_ref, 'r') as git_head_ref_file:
    commit_id = git_head_ref_file.read().strip()[:7]

if you want a bit more data than the hash, you can use git-log:

import subprocess

def get_git_hash():
    return subprocess.check_output(['git', 'log', '-n', '1', '--pretty=tformat:%H']).strip()

def get_git_short_hash():
    return subprocess.check_output(['git', 'log', '-n', '1', '--pretty=tformat:%h']).strip()

def get_git_short_hash_and_commit_date():
    return subprocess.check_output(['git', 'log', '-n', '1', '--pretty=tformat:%h-%ad', '--date=short']).strip()

for full list of formating options – check out git log --help

If you are like me :

• Multiplatform so subprocess may crash one day
• Using Python 2.7 so GitPython not available
• Don’t want to use Numpy just for that
• Already using Sentry (old depreciated version : raven)

Then (this will not work on shell because shell doesn’t detect current file path, replace BASE_DIR by your current file path) :

import os
import raven

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
print(raven.fetch_git_sha(BASE_DIR))

That’s it.

I was looking for another solution because I wanted to migrate to sentry_sdk and leave raven but maybe some of you want to continue using raven for a while.

Here was the discussion that get me into this stackoverflow issue

So using the code of raven without raven is also possible (see discussion) :

from __future__ import absolute_import

import os.path

__all__ = 'fetch_git_sha'


def fetch_git_sha(path, head=None):
    """
    >>> fetch_git_sha(os.path.dirname(__file__))
    """
    if not head:
        head_path = os.path.join(path, '.git', 'HEAD')

        with open(head_path, 'r') as fp:
            head = fp.read().strip()

        if head.startswith('ref: '):
            head = head[5:]
            revision_file = os.path.join(
                path, '.git', *head.split('/')
            )
        else:
            return head
    else:
        revision_file = os.path.join(path, '.git', 'refs', 'heads', head)

    if not os.path.exists(revision_file):
        # Check for Raven .git/packed-refs' file since a `git gc` may have run
        # https://git-scm.com/book/en/v2/Git-Internals-Maintenance-and-Data-Recovery
        packed_file = os.path.join(path, '.git', 'packed-refs')
        if os.path.exists(packed_file):
            with open(packed_file) as fh:
                for line in fh:
                    line = line.rstrip()
                    if line and line[:1] not in ('#', '^'):
                        try:
                            revision, ref = line.split(' ', 1)
                        except ValueError:
                            continue
                        if ref == head:
                            return revision

    with open(revision_file) as fh:
        return fh.read().strip()

I named this file versioning.py and I import "fetch_git_sha" where I need it passing file path as argument.

Hope it will help some of you 😉

This is an improvement of Yuji ‘Tomita’ Tomita answer.

import subprocess

def get_git_revision_hash():
    full_hash = subprocess.check_output(['git', 'rev-parse', 'HEAD'])
    full_hash = str(full_hash, "utf-8").strip()
    return full_hash

def get_git_revision_short_hash():
    short_hash = subprocess.check_output(['git', 'rev-parse', '--short', 'HEAD'])
    short_hash = str(short_hash, "utf-8").strip()
    return short_hash

print(get_git_revision_hash())
print(get_git_revision_short_hash())

I ran across this problem and solved it by implementing this function.
https://gist.github.com/NaelsonDouglas/9bc3bfa26deec7827cb87816cad88d59

from pathlib import Path

def get_commit(repo_path):
    git_folder = Path(repo_path,'.git')
    head_name = Path(git_folder, 'HEAD').read_text().split('n')[0].split(' ')[-1]
    head_ref = Path(git_folder,head_name)
    commit = head_ref.read_text().replace('n','')
    return commit


r = get_commit('PATH OF YOUR CLONED REPOSITORY')
print(r)

I had a problem similar to the OP, but in my case I’m delivering the source code to my client as a zip file and, although I know they will have python installed, I cannot assume they will have git. Since the OP didn’t specify his operating system and if he has git installed, I think I can contribute here.

To get only the hash of the commit, Naelson Douglas’s answer was perfect, but to have the tag name, I’m using the dulwich python package. It’s a simplified git client in python.

After installing the package with pip install dulwich --global-option="--pure" one can do:

from dulwich import porcelain

def get_git_revision(base_path):
    return porcelain.describe(base_path)

r = get_git_revision("PATH OF YOUR REPOSITORY's ROOT FOLDER")
print(r)

I’ve just run this code in one repository here and it showed the output v0.1.2-1-gfb41223, similar to what is returned by git describe, meaning that I’m 1 commit after the tag v0.1.2 and the 7-digit hash of the commit is fb41223.

It has some limitations: currently it doesn’t have an option to show if a repository is dirty and it always shows a 7-digit hash, but there’s no need to have git installed, so one can choose the trade-off.

Edit: in case of errors in the command pip install due to the option --pure (the issue is explained here), pick one of the two possible solutions:

1. Install Dulwich package’s dependencies first:
   pip install urllib3 certifi && pip install dulwich --global-option="--pure"
2. Install without the option pure: pip install dulwich. This will install some platform dependent files in your system, but it will improve the package’s performance.