Linode: check that the currently running kernel is up to date.

linode_kernel_check.py

#!/usr/bin/python
# Copyright 2012 Daniel Richman.
# Protip: need not be run as root.

import sys
import os
import urllib2
import xml.dom.minidom
import traceback

def expect():
    f = urllib2.urlopen("http://www.linode.com/kernels/rss.xml")
    d = xml.dom.minidom.parse(f)
    f.close()

    items = d.getElementsByTagName("item")
    latest = None

    for i in items:
        x = i.getElementsByTagName("title")
        assert len(x) == 1
        t = x[0]
        assert t.firstChild == t.lastChild
        s = t.firstChild
        kernel = s.nodeValue

        if "Latest" not in kernel or "x86_64" not in kernel:
            continue

        (_, p, kernel) = kernel.partition('(')
        assert p == '('
        (kernel, p, _) = kernel.partition(')')
        assert p == ')'
        kernel = str(kernel)

        assert not latest and kernel
        latest = kernel

    return latest

def current():
    (_, _, kernel, _, _) = os.uname()
    assert kernel
    return kernel

def main():
    e = expect()
    c = current()

    if e != c:
        print "Kernel is not up to date!"
        print "Latest: ", e
        print "Current:", c

if __name__ == "__main__":
    main()