#!/usr/bin/python3
# check the version string of the latest gitlab security release
# compare it to the previous version and send an email if it has changed since last check
# https://phabricator.wikimedia.org/T323932
# we are using feedparse to parse the upstream XML feed
#
# requirements: python3-path, python3-feedparser (Debian packages)
#
###
import feedparser
import os
import filecmp
import shutil
import smtplib
from email.message import EmailMessage
from pathlib import Path
###

###
gitlab_release_cur_file = '/tmp/gitlab_release_cur'
gitlab_release_prev_file = '/tmp/gitlab_release_prev'
gitlab_release_feed_url = 'https://about.gitlab.com/security-releases.xml'
email_rcpt_addr = 'dzahn@wikimedia.org'
email_sndr_addr = 'root@localhost'
email_text_msg = 'detected a new gitlab release:'
###

print(f'gitlab version checker - pulling release string from {gitlab_release_feed_url}\n')

version_feed = feedparser.parse(gitlab_release_feed_url)

if version_feed.status == 200:
    version = version_feed['entries'][0]['title']
    gitlab_release_current_file = open(gitlab_release_cur_file, "w")
    gitlab_release_current_file.write(version)
    gitlab_release_current_file.close()
else:
    print(f'could not pull feed from {gitlab_release_feed_url}. status code: {d.status}\n')
    exit('check network connectivity and feed manually. exiting.\n')

if os.path.exists(gitlab_release_prev_file):
        print(f'found a release string from a previous check in {gitlab_release_prev_file}.\n')
        if filecmp.cmp(gitlab_release_prev_file, gitlab_release_cur_file):
            print(f'old and new version string are the same. doing nothing.\n')
        else:
            print(f'old and new version string differ. sending an email.\n')
            new_version_string = Path(gitlab_release_cur_file).read_text()
            msg = EmailMessage()
            msg.set_content("{email_text_msg} {new_version_string}")
            msg['Subject'] = f'{email_text_msg}'
            msg['From'] = email_sndr_addr
            msg['To'] = email_rcpt_addr
            s = smtplib.SMTP('localhost')
            s.send_message(msg)
            s.quit()
else:
        print(f'could not find a previous version ({gitlab_release_prev_file}).\nlooks like you are running this for the first time.\n')
        print(f'copying {gitlab_release_cur_file} to {gitlab_release_prev_file}\n')
        shutil.copyfile(gitlab_release_cur_file, gitlab_release_prev_file)

 python3 gitlab_version_check.py 

gitlab version checker - pulling release string from https://about.gitlab.com/security-releases.xml

could not find a previous version (/tmp/gitlab_release_prev).
looks like you are running this for the first time.

copying /tmp/gitlab_release_cur to /tmp/gitlab_release_prev

python3 gitlab_version_check.py 
gitlab version checker - pulling release string from https://about.gitlab.com/security-releases.xml

found a release string from a previous check in /tmp/gitlab_release_prev.

old and new version string are the same. doing nothing.

python3 gitlab_version_check.py 
gitlab version checker - pulling release string from https://about.gitlab.com/security-releases.xml

found a release string from a previous check in /tmp/gitlab_release_prev.

old and new version string differ. sending an email.

...