gitlab-hook-postcommit-coloremail

#!/usr/bin/env python
# gitlab-hook-postcommit-coloremail (part of ossobv/vcutil)
#   // wdoekes/2013-2016 // Public Domain
#
# Sends out a nice colored e-mail with the committed changeset for
# each committed revision. It uses the awesome vim(1) syntax
# highlighting to colorize the patch files.
#
# Installation:
#
#     Read about web hooks here: http://YOUR_GITLAB/help/web_hooks
#     Basically, it sends out a JSON blob as HTTP POST data to your web
#     hook. You can configure this script to run on a CGI webserver
#     on the local machine.
#
#     Then, go to: https://YOUR_GITLAB/YOUR_PROJECT/hooks
#     Add the URL to the local CGI webserver, e.g.:
#         http://127.0.0.1:81/hooks/gitlab-hook-postcommit-coloremail
#
# Example lighttpd config:
#
#     server.pid-file             = "/var/run/lighttpd.pid"
#     server.username             = "www-data"
#     # Observe that we need gitlab read powers!
#     server.groupname            = "git"
#     server.bind                 = "127.0.0.1"
#     server.port                 = 81
#     server.errorlog             = "/var/log/lighttpd/error.log"
#     server.breakagelog          = "/var/log/lighttpd/breakage.log"
#     server.document-root        = "/srv/lighttpd-cgi"
#     server.modules = (
#         "mod_cgi",
#         "mod_setenv"
#     )
#     cgi.execute-x-only = "enable"
#     # (Add .py suffix to this script.)
#     cgi.assign = (".py" => "/usr/bin/python")
#     setenv.add-environment = (
#         "GITLAB_HOOK_RC" => "/srv/lighttpd-cgi/gitlab-hook-rc.py"
#     )
#
# Example usage:
#
#     ./gitlab-hook-postcommit-coloremail \
#         < gitlab-hook-postcommit-coloremail.example
#
# Todo:
#
#     * Allow MAIL_TO to be passed as QUERY_STRING.
#
from __future__ import print_function
import json
import os
import smtplib
import string
import tempfile
import traceback
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.utils import formatdate
from subprocess import check_output  # python2.7+


# Settings:
if 'PATH' not in os.environ:  # lighttpd unsets it: we lose /usr/local/bin
    os.environ['PATH'] = '/usr/local/bin:/usr/bin:/bin'
REPOSITORIES_ROOT = '/home/git/repositories/'
MAIL_SERVER = '127.0.0.1'
MAIL_FROM = 'gitlab@example.com'
MAIL_TO = ['commits@example.com']  # list of recipients
SUBJECT = '[%(project)s] %(shortid)s %(author)s: %(summary)s'
BODY_PREFIX = 'URL: %(url)s\n\n'
BODY_SUFFIX = (u'diff ENDS HERE\n' + (72 * u'=') + u'\n'
               u'D\u20acBUG: %(gitlab_json)s\n')


def update_globals_from_file(filename):
    """
    Read a python file with updated globals.

        # Example gitlab-hook-rc.py
        MAIL_FROM = 'git@mycompany.com
        MAIL_SERVER = 'smtp.mycompany.com'
    """
    globals_ = {}
    locals_ = {}
    try:
        with open(filename, 'r') as source_file:
            code = compile(source_file.read(), filename, 'exec')
    except IOError:
        return
    else:
        exec(code, globals_, locals_)
    uppercase_values = dict(
        (key, value) for (key, value) in locals_.items()
        if key[0].isupper())
    globals().update(uppercase_values)


def is_daemon_child():
    pid = os.fork()
    if pid:
        # Reap the zombie by fetching the return value. The second fork ensures
        # that that's done quickly.
        os.waitpid(pid, 0)
        return False

    # For a process to be truly daemonized (ran in the background) we should
    # ensure that the session leader is killed so that there is no possibility
    # of the session ever taking control of the TTY.
    os.setsid()

    # Second fork, do it as soon as possible.
    if os.fork():
        os._exit(0)

    # Begin cleanup after ourselves. Release mount points and close fd's.
    os.chdir('/')
    os.closerange(0, 4095)

    # We're daemonized.
    return True


def usernameify(full_name):
    """
    Take initials of full name, join and convert to lowercase.

    >>> usernameify('Walter Jakob Doekes')
    'wjdoekes'
    """
    names = [i.strip() for i in full_name.split(' ') if i.strip()]
    surname = names.pop(-1)
    username = ''.join(i[0] for i in names) + surname
    username = ''.join(i for i in username.lower()
                       if i in string.ascii_lowercase + string.digits)
    return username


def diff_to_html(diff):
    """
    Ask vim(1) to colorize the diff and return it as html.
    """
    txttmp = tempfile.mktemp()  # vim will write to txttmp+'.html'(!)
    htmltmp = txttmp + '.html'
    try:
        # Write text to txttmp.
        with open(txttmp, 'w') as txt:
            txt.write(diff.encode('UTF-8'))
        # Call vim(1) on it.
        DEVZERO = open('/dev/zero', 'r')  # yes(1) is not happy without stdin
        DEVNULL = open('/dev/null', 'w')
        output = check_output(
            'yes | vim -n -T builtin_ansi -c '
            "'syn on|set syn=diff|set enc=utf8|set bg=dark|runtime "
            "syntax/2html.vim|wqa' "
            '"%(txttmp)s" 2>&1 >/dev/null | '
            "grep -v '^Vim: Warning: '; true" % {'txttmp': txttmp},
            stdin=DEVZERO, stderr=DEVNULL, shell=True
        )
        DEVZERO.close()
        DEVNULL.close()
        if output:
            raise ValueError('vim returned this: %r' % (output,))
        # Read htmltmp.
        with open(htmltmp, 'r') as html:
            diff_html = html.read()
        # Should not fail, but let's just handle the case when some crap
        # does enter the output.
        diff_html = diff_html.decode('UTF-8', 'replace')
    finally:
        try:
            os.unlink(txttmp)
        except Exception:
            pass
        try:
            os.unlink(htmltmp)
        except Exception:
            pass

    return diff_html


def send_mails(decoded):
    # Init vars.
    pushvars = {}
    pushvars['project'] = decoded['repository']['name']
    pushvars['pusher'] = decoded['user_name']
    pushvars['homepage'] = decoded['repository']['homepage']
    pushvars['commit_count'] = decoded['total_commits_count']
    pushvars['gitlab_json'] = json.dumps(decoded, indent=4)

    # Fetch changeset and colorize it.
    os.chdir(os.path.join(REPOSITORIES_ROOT,
                          decoded['repository']['url'].split(':', 1)[-1]))
    for commit in decoded['commits']:
        # Get local vars.
        commitvars = pushvars.copy()
        commitvars['id'] = commit['id']
        commitvars['shortid'] = commit['id'][0:7]
        commitvars['author'] = usernameify(commit['author']['name'])
        commitvars['summary'] = commit['message'].split('\n')[0].strip()
        commitvars['url'] = commit['url']
        # `git show -p` output already provides enough info to populate a body.
        changes = check_output(['git', 'show', '-p', commit['id']],
                               stdin=None, stderr=None, shell=False)
        # `echo "$changes" | censored-for-email` to censor #CENSORED\# bits.
        with tempfile.NamedTemporaryFile() as changes_file:
            changes_file.write(changes)
            changes_file.flush()
            changes_file.seek(0)
            try:
                # Why do we call an external app? Because we don't want to
                # duplicate the censorship code. Recoding the censored-for-
                # email app into python is easy, but less flexible.
                changes = check_output(['censored-for-email'],
                                       stdin=changes_file, stderr=None,
                                       shell=False)
            except OSError:
                # The censored-for-email(1) program wasn't found. Never mind.
                pass
        # Translate to unicode so we can recode non-UTF-8 to UTF-8.
        try:
            changes = changes.decode('UTF-8')
        except UnicodeDecodeError:
            # From: WIKIPEDIA/Windows-1252
            # > Most modern web browsers and e-mail clients treat the MIME
            # > charset ISO-8859-1 as Windows-1252 to accommodate such
            # > mislabeling. This is now standard behavior in the draft
            # > HTML 5 specification, which requires that documents
            # > advertised as ISO-8859-1 actually be parsed with the
            # > Windows-1252 encoding.
            # This is probably the most common 8-bit encoding.
            changes = changes.decode('CP1252', 'replace')
        # Trim changeset to 256KB, which would become about the double
        # in colored html. That should be low enough to pass through
        # most mail exchanges -- the common low limit being 2MB.
        if len(changes) > (256 * 1024):
            extra_prefix = ('NOTE: this changeset was truncated from '
                            '%d KB to 256 KB for e-mail transport\n\n' %
                            (len(changes) / 1024,))
            extra_suffix = '\n... truncated ...\n'
            changes = changes[0:(256 * 1024)]
        else:
            extra_prefix = extra_suffix = ''
        # Prefix the changes with a bit of extra body.
        changes = ''.join([BODY_PREFIX % commitvars,
                           extra_prefix,
                           changes,
                           extra_suffix,
                           BODY_SUFFIX % commitvars])
        # Colorize it using vim.
        changes_html = diff_to_html(changes)
        # Compile a mail and send.
        msg = MIMEMultipart('alternative')
        msg['Subject'] = SUBJECT % commitvars
        msg['From'] = MAIL_FROM
        msg['To'] = ', '.join(MAIL_TO)
        msg['Date'] = formatdate(localtime=True)
        msg.attach(MIMEText(changes, 'plain', _charset='UTF-8'))
        msg.attach(MIMEText(changes_html, 'html', _charset='UTF-8'))
        s = smtplib.SMTP(MAIL_SERVER)
        s.sendmail(MAIL_FROM, MAIL_TO, msg.as_string())
        s.quit()


def get_stdin():
    data = []
    try:
        while True:
            in_ = input()
            if not in_:
                break
            data.append(in_)
    except EOFError:
        pass
    return '\n'.join(data)


# Optionally update settings
GITLAB_HOOK_RC = os.environ.get(
    'GITLAB_HOOK_RC', '/etc/gitlab-hook-rc.py')
update_globals_from_file(GITLAB_HOOK_RC)

# If this is a POST request, daemonize and send OK to caller. If we're
# ran from the CLI, don't daemonize and don't print any HTTP status.
is_cgi = bool(os.environ.get('REQUEST_METHOD'))  # GET/POST/HEAD

# Get data, must be done in the foreground.
stdin = get_stdin()

if not is_cgi:
    # Do everything in the foreground (testing mode).
    decoded = json.loads(stdin.decode('utf-8'))
    send_mails(decoded)

elif is_daemon_child():
    # Do that mailing as a background job.
    try:
        decoded = json.loads(stdin.decode('utf-8'))
        send_mails(decoded)
    except Exception:
        backtrace = traceback.format_exc()
        msg = MIMEText(backtrace + '\n\n\n' + stdin)
        msg['Subject'] = 'ERROR in gitlab-hook-postcommit-coloremail'
        msg['From'] = MAIL_FROM
        msg['To'] = ', '.join(MAIL_TO)
        msg['Date'] = formatdate(localtime=True)
        s = smtplib.SMTP(MAIL_SERVER)
        s.sendmail(MAIL_FROM, MAIL_TO, msg.as_string())
        s.quit()

else:
    # Output back to webserver.
    print(b"Content-Type: text/plain\r\n\r\nOK")

# vim: set ts=8 sw=4 sts=4 et ai tw=79: