scripts/voixicron.py

#! /usr/bin/env python3
"""
This script checks for available updates on Void Linux using xbps and notifies
the configured administrator account about them. It currently requires
python 3.x and no additional packages and is supposed to be run with cron or
another scheduled execution mechanism.
"""

import subprocess
import smtplib
import socket
import re

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText


# Email server to be used to send the notification
ADMIN_EMAIL = "root"
# Mail server to be used to send the notification
MAIL_SERVER = "localhost"
# Port to use on the mail server
MAIL_SERVER_PORT = 25
# User name to log in to the mail server
MAIL_SERVER_USER = ""
# Password to log in to the mail server
MAIL_SERVER_PASSWORD = ""

AVAILABLE_UPDATES = []

DEVNULL = open("/dev/null", "w")

try:
    XBPS_INSTALL_RESULT = subprocess.check_output(["xbps-install", "-Sun"],
                                                  stderr=DEVNULL)
except subprocess.CalledProcessError:
    pass
else:
    XBPS_INSTALL_RESULT = XBPS_INSTALL_RESULT.decode("utf-8").split("\n")
    for line in XBPS_INSTALL_RESULT:
        if "update" in line:
            try:
                package = line.split(" ")[0]
                package_regex = "^([A-Za-z0-9-]*)-([0-9].*_[0-9])$"
                match_object = re.match(package_regex, package)
                package_name = match_object.groups()[0]
                new_package_version = match_object.groups()[1]
            except IndexError:
                continue
            else:
                try:
                    xbps_query_result = subprocess.check_output(
                        ["xbps-query", "--show", package_name], stderr=DEVNULL)
                except subprocess.CalledProcessError:
                    pass
                else:
                    xbps_query_result = xbps_query_result.decode(
                        "utf-8").split("\n")
                    for line in xbps_query_result:
                        if "pkgver" in line:
                            installed_package = line.split(
                                ":")[1].strip()
                            match = re.match(package_regex,
                                                       installed_package)
                            installed_package_version = match.groups()[1]
                            package_update = {
                                "name": package_name,
                                "new_version": new_package_version,
                                "old_version": installed_package_version,
                            }
                            AVAILABLE_UPDATES.append(package_update)
                            break
if AVAILABLE_UPDATES:
    HOSTNAME = socket.getfqdn()
    MSG = MIMEMultipart()
    MAIL_TEXT = "The following package updates are available on host %s:\n\n"\
                % HOSTNAME
    MSG["Subject"] = "%s updates available on host %s"\
                     % (len(AVAILABLE_UPDATES), HOSTNAME)
    MSG["From"] = "voixicron@%s" % HOSTNAME
    MSG["To"] = ADMIN_EMAIL
    for update in AVAILABLE_UPDATES:
        MAIL_TEXT += "%s (%s -> %s)\n"\
                     % (update["name"],
                        update["old_version"],
                        update["new_version"])
    MSG_TEXT = MIMEText(MAIL_TEXT.encode("utf-8"), _charset="utf-8")
    MSG.attach(MSG_TEXT)
    SERVER_CONNECTION = smtplib.SMTP(MAIL_SERVER, MAIL_SERVER_PORT)
    try:
        SERVER_CONNECTION.connect()
    except (smtplib.SMTPConnectError, smtplib.SMTPServerDisconnected,
            socket.error):
        pass
    else:
        try:
            SERVER_CONNECTION.starttls()
        except smtplib.SMTPException:
            pass
        if MAIL_SERVER_USER:
            try:
                SERVER_CONNECTION.login(MAIL_SERVER_USER, MAIL_SERVER_PASSWORD)
            except smtplib.SMTPAuthenticationError:
                pass
            except smtplib.SMTPException:
                pass
        try:
            SERVER_CONNECTION.sendmail("voixicron@%s" % HOSTNAME, ADMIN_EMAIL,
                                       MSG.as_string())
        except smtplib.SMTPRecipientsRefused:
            pass
        except smtplib.SMTPSenderRefused:
            pass
        else:
            SERVER_CONNECTION.quit()
DEVNULL.close()