Check for ubuntu pending updates

packages.py

# modified from   /usr/lib/update-notifier/apt-check
import subprocess


def checkUpgrades():
    import apt_pkg

    DISTRO = subprocess.check_output(["lsb_release", "-c", "-s"],    universal_newlines=True).strip()

    def isSecurityUpgrade(ver):
        " check if the given version is a security update (or masks one) "
        security_pockets = [("Ubuntu", "%s-security" % DISTRO),
                            ("gNewSense", "%s-security" % DISTRO),
                            ("Debian", "%s-updates" % DISTRO)]
        for (file, index) in ver.file_list:
            for origin, archive in security_pockets:
                if (file.archive == archive and file.origin == origin):
                    return True
        return False

    apt_pkg.init()
    cache= apt_pkg.Cache()
    depcache=apt_pkg.DepCache(cache)
    depcache.upgrade(True)

    total=0
    security=0
    for package in cache.packages: 
        if not (depcache.marked_install(package) or depcache.marked_upgrade(package)):
            continue

        installed_version = package.current_ver
        candidate_version = depcache.get_candidate_ver(package)
        if installed_version==candidate_version:continue
        total+=1
        if isSecurityUpgrade(candidate_version):
            security+=1

    return {
        "total":total,
        "security":security
    }