Cross-grade helper script

crossgrade-apt.py

# Copyright 2016 Tom Parker/Oliver Wyman, opensource@lshift.net
# License: AGPLv3
import apt_pkg
import os
import subprocess

apt_pkg.init()
cache = apt_pkg.Cache()
sourcelist = apt_pkg.SourceList()
sourcelist.read_main_list()
dc = apt_pkg.DepCache(cache)
pr = apt_pkg.PackageRecords(cache)
if not cache.is_multi_arch:
    raise Exception, "Need multi-arch apt_pkg"

null = open(os.devnull,"w")

def install_version(pkg, version):
    print "%s: Installing %s:%s" % (pkg.name, version.ver_str, version.arch)
    dc2 = apt_pkg.DepCache(cache)
    dc2.init()
    pm = apt_pkg.PackageManager(dc2)
    acq = apt_pkg.Acquire()

    dc2.set_candidate_ver(pkg, version)
    dc2.mark_install(pkg, False)
    pm.get_archives(acq, sourcelist, pr)
    if acq.run() != 0:
        raise Exception
    for item in acq.items:
        if item.error_text != "":
            raise Exception, item
        print "%s: Installing %s" % (pkg.name, item.destfile)
        try:
            subprocess.check_output(["dpkg", "-i", item.destfile], stderr=subprocess.STDOUT)
        except subprocess.CalledProcessError:
            pass # Assume it's due to other package issues that will get resolved later

def install_package(pkg, other_pkg):
    version = other_pkg.current_ver
    selected = [x for x in pkg.version_list if x.ver_str == version.ver_str]
    if len(selected) == 1:
        install_version(pkg, selected[0])
        return
    selected = [x for x in pkg.version_list if apt_pkg.version_compare(version.ver_str, x.ver_str) < 0]
    selected.sort(cmp=lambda x,y: apt_pkg.version_compare(x.ver_str,y.ver_str))
    if len(selected) == 0:
        if len(pkg.version_list) == 0:
            print "%s: Assuming local install as no candidate versions, skipping" % pkg.name
        else:
            raise Exception, pkg.version_list
    else:
        install_version(other_pkg, selected[0])
        install_version(pkg, selected[0])

for pkg in cache.packages:
    if pkg.architecture != "amd64":
        continue
    p = pkg.name
    no_arch = cache[p]
    if no_arch.version_list == []:
        continue # skip things without versions
    if no_arch.version_list[-1].arch == "all":
        continue # skip Arch:all
    try:
        amd64 = cache[p, "amd64"]
    except KeyError:
        print "%s: Can't find package for amd64, assuming local install, and skipping" % p
        continue
    try:
        i386 = cache[p, "i386"]
    except KeyError:
        # Architecture: all, so could skip
        continue
    if i386.current_ver == None:
        if i386.inst_state == 0 and i386.current_state == 0:
            # Assume not needed
            continue
        if i386.selected_state in [3,4]: # Deinstall or Purge
            if amd64.current_ver == None:
                print "%s: No amd64 version!" % p
            else:
                subprocess.check_call(["dpkg", "--purge", "%s:i386" % pkg.name])
            continue
        print pkg
        print "Selected: %d, inst: %d, current: %d"% (i386.selected_state, i386.inst_state, i386.current_state)
        print "See https://github.com/mvo5/apt/blob/master/apt-pkg/pkgcache.h#L164 for information"
        raise Exception
    print "%s: i386" % p, i386.current_ver
    if amd64.current_ver != None and amd64.current_ver.arch == "all":
        print "%s: Architecture:all, so skip" % p
        continue
    print "%s: amd64" % p, amd64.current_ver
    if amd64.current_ver == None and i386.current_ver != None:
        install_package(amd64, i386)
    elif dc.is_inst_broken(amd64):
        if i386.current_ver == None:
            print "%s: No i386, amd64 broken, assuming fixed later..." % p
        elif amd64.current_ver.ver_str != i386.current_ver.ver_str:
            print "%s: %s (amd64) != %s (i386)" % (p, amd64.current_ver.ver_str, i386.current_ver.ver_str)
            comp = apt_pkg.version_compare(amd64.current_ver.ver_str, i386.current_ver.ver_str)
            if comp > 0:
                install_package(i386, amd64)
            elif comp < 0:
                install_package(amd64, i386)
            else:
                raise Exception
        else:
            print "%s: i386==amd64, and the latter is broken, assuming fixed later..." % p
    else:
        print "%s: All ok apparently!" % p
        # multi-arch spec https://github.com/mvo5/apt/blob/master/apt-pkg/pkgcache.h#L623
        if amd64.current_ver.multi_arch == 4:
            continue
        print amd64.current_ver.multi_arch
        raise Exception