#!/usr/bin/python
""" Differential backup script using rsync with possibility to define multiple media
Author : Marc SCHNEIDER
"""

import getopt, os, sys


NICE_LEVEL = 3
USER_HOME = '/home/arch'

DIR_TO_BACKUP = {
    'icybox': "/home/arch/scripts --exclude=temp/ --exclude=tmp/",
    'lacie' : "/home/data /home/data2 --exclude=temp/ --exclude=tmp/",
    'darmstadt' : "/home/arch/scripts",
}

BACKUP_DEST = {
    'icybox': {'dir': '/media/icybox/backup',},
    'lacie':  {'dir': '/media/lacie/backup'},
    'darmstadt': {
        'dir': '/home/backup',
        'server': 'darmstadt.plop.org',
        'port': '2222',
        'login': 'toto',
    },
}

ARCHIVE_NB = {
    'icybox': 15,
    'lacie': 15,
    'darmstadt': 10,
}

def backup(media_name):
    is_remote = BACKUP_DEST[media_name].has_key('server')
    ssh_string = ""
    if is_remote:
        ssh_string = "ssh -p %s -l %s %s"\
                      % (BACKUP_DEST[media_name]['port'], BACKUP_DEST[media_name]['login'],\
                         BACKUP_DEST[media_name]['server'])
    print "Running backup on %s..." % media_name

    # Remove oldest backup directory
    dir_to_remove = BACKUP_DEST[media_name]['dir']+"/daily."+str(ARCHIVE_NB[media_name] - 1)
    exist_dir_cmd = "[ -d %s ]" % dir_to_remove
    rm_dir_cmd = "rm -rf %s" % dir_to_remove
    if is_remote:
        exist_dir_cmd = "%s %s" % (ssh_string, exist_dir_cmd)
        rm_dir_cmd = "%s %s" % (ssh_string, rm_dir_cmd)

    if os.system(exist_dir_cmd) == 0:
        print "Removing directory", dir_to_remove
        if os.system(rm_dir_cmd) != 0:
            print "Couldn't remove %s" % dir_to_remove

    # Shift the snapshots back by one if they exist
    for i in reversed(range(2, ARCHIVE_NB[media_name])):
        src_dir = BACKUP_DEST[media_name]['dir']+"/daily."+str(i-1)
        dest_dir = BACKUP_DEST[media_name]['dir']+"/daily."+str(i)
        exist_dir_cmd = "[ -d %s ]" % src_dir
        mv_dir_cmd = "mv %s %s" % (src_dir, dest_dir)
        if is_remote:
            exist_dir_cmd = "%s %s" % (ssh_string, exist_dir_cmd)
            mv_dir_cmd = "%s %s" % (ssh_string, mv_dir_cmd)
        if os.system(exist_dir_cmd) == 0:
            print "Moving %s to %s" % (src_dir, dest_dir)
            if os.system(mv_dir_cmd) != 0:
                print "Couldn't move directory %s to %s" % (src_dir, dest_dir)

    # Make a hard-link copy (except for directories) of the latest snapshot
    last_backup_dir = BACKUP_DEST[media_name]['dir']+"/daily.0"
    dest_backup_dir = BACKUP_DEST[media_name]['dir']+"/daily.1"
    copy_cmd = "cp -al %s %s" % (last_backup_dir, dest_backup_dir)
    mkdir_cmd = "mkdir %s" % last_backup_dir
    exist_dir_cmd = "[ -d %s ]" % last_backup_dir
    if is_remote:
        copy_cmd = "%s %s" % (ssh_string, copy_cmd)
        mkdir_cmd = "%s %s" % (ssh_string, mkdir_cmd)
        exist_dir_cmd = "%s %s" % (ssh_string, exist_dir_cmd)
    if os.system(exist_dir_cmd) == 0:
        # Directory exists
        print "Executing", copy_cmd
        if os.system(copy_cmd) !=0:
            print "Couldn't execute", copy_cmd
    else:
        print "Creating directory", last_backup_dir
        if os.system(mkdir_cmd) != 0:
            print "Couldn't create directory", last_backup_dir

    # Run rsync from local directories to the latest snapshot (daily.0)
    # rsync behaves like cp --remove-destination by default, so the destination
    # is unlinked first.  If it were not so, this would copy over the other snapshot(s) too!
    rsync_cmd = "nice --adjust %s rsync -va --progress --relative --delete --delete-excluded %s "\
                 % (NICE_LEVEL, DIR_TO_BACKUP[media_name])
    if is_remote:
        rsync_cmd += " -e \"ssh -p %s\" %s@%s:"\
                      % (BACKUP_DEST[media_name]['port'], BACKUP_DEST[media_name]['login'],\
                         BACKUP_DEST[media_name]['server'])
    rsync_cmd = "%s%s" % (rsync_cmd, BACKUP_DEST[media_name]['dir']+"/daily.0")
    print "Executing", rsync_cmd
    if os.system(rsync_cmd) != 0:
        print "Couldn't execute", rsync_cmd

    # Update mtime of daily.0 to reflect the snapshot time
    touch_cmd = "touch %s/daily.0" % BACKUP_DEST[media_name]['dir']
    if is_remote:
        touch_cmd = ssh_string + " " + touch_cmd
    if os.system(touch_cmd) != 0:
        print "Couldn't execute touch command", touch_cmd

def usage():
    print "Usage : backup.py command"
    print "Where command can be one of :"
    print "-i, --icybox"
    print "-c, --lacie"
    print "-d, --darmstadt"

if __name__ == "__main__":
    if len(sys.argv[1:]) == 0:
        usage()
        sys.exit(2)
    try:
        opts, args = getopt.getopt(sys.argv[1:], "hicd", ["help", "icybox", "lacie", "darmstadt"])
    except getopt.GetoptError:
        usage()
        sys.exit(2)
    if os.getuid() != 0:
        print "Sorry you must be 'root' to run this program"
        sys.exit(2)
    for opt, arg in opts:
        if opt in ('-h', '--help'):
            usage()
            sys.exit()
        if opt in ('-i', '--icybox'):
            backup('icybox')
        if opt in ('-c', '--lacie'):
            backup('lacie')
        if opt in ('-d', '--darmstadt'):
            backup('darmstadt')