Hardlink backup with rsync

rsync_backup.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
import sys, os, popen2, time, subprocess

SRC = "/"
HOST = "user@host"
DEST = "/backup_module/%(DATE)s/"
LINK_DEST = "/%(LAST_DATE)s"
EXCLUDE = ["/home/henryk/_secure", "/home/henryk/mnt", "/tmp", "/home/henryk/tmp"]
OPTIONS = ["-HAXax", "--stats", "--delete", "-b"]
TIMESTAMP_FILE = "/home/henryk/.backup_dates/%(host)s__%(src)s__%(dest)s"

#PASSWORD = "REDACTED"
PASSWORD = None

def check_host(hostname):
    cmd = ["rsync", "rsync://%s/" % hostname]
    p = popen2.Popen3(cmd)
    return p.wait() == 0

def _format_timestamp_file(host, src, dest):
    host = host.replace("/", "_")
    src = src.replace("/", "_")
    dest = dest.replace("/", "_")
    return TIMESTAMP_FILE % locals()
    
def get_last_date(*args, **kwargs):
    if TIMESTAMP_FILE is None: return None
    fname = _format_timestamp_file(*args, **kwargs)
    
    result = None
    try:
        fp = file(fname, "r")
        result = fp.read().strip()
        fp.close()
    except: pass
    return result

def set_last_date(last_date, *args, **kwargs):
    if TIMESTAMP_FILE is None: return None
    fname = _format_timestamp_file(*args, **kwargs)
    
    try:
        fp = file(fname, "w")
        fp.write(last_date)
        fp.close()
    except: 
        print >>sys.stderr, "Warning: Couldn't write timestamp file"

def prepare_exclude(exclude, src):
    result = []
    for name in exclude:
        if name.startswith(src):
            name = name[len(src):]
            if not name.startswith("/"): name = "/" + name
        result.append("--exclude=%s" % name)
    return result

if __name__ == "__main__":
    
    DATE = time.strftime("%Y-%m-%d",time.gmtime())
    LAST_DATE = get_last_date(HOST, SRC, DEST)
    
    if LAST_DATE is not None:
        if cmp(LAST_DATE, DATE) != -1:
            print >>sys.stderr, "Error: Last Backup is not at least one day away, aborting"
            sys.exit(1)

    if not check_host(HOST):
        print >>sys.stderr, "Error: Rsync not available, aborting"
        sys.exit(1)

    print "Start %s" % time.strftime("%a, %d %b %Y %H:%M:%S %z")
    
    command = ["rsync"] + OPTIONS + prepare_exclude(EXCLUDE, SRC)
    if LINK_DEST is not None:
        if "%(LAST_DATE)s" in LINK_DEST and LAST_DATE is None:
            pass
        else:
            command.append( "--link-dest=%s" % (LINK_DEST % locals()) )
    
    if PASSWORD is not None:
        rpipe, wpipe = os.pipe()
        os.write(wpipe, PASSWORD+"\n")
        command.append("--password-file=/dev/fd/%i" % rpipe)
    
    command.append(SRC)
    command.append("rsync://%s%s" % (HOST, DEST % locals()))
    
    retcode = subprocess.call(command)
    
    print "Stop %s" % time.strftime("%a, %d %b %Y %H:%M:%S %z")
    
    if retcode in [0,23,24]:
        set_last_date(DATE, HOST, SRC, DEST)
    sys.exit(retcode)