python snippet to handle uschedule jobs

python-uschedule.py

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=utf-8

"""
Python uschedule handler
------------------------
This module provide a methods to handle uschedule_ scheduler by Uwe Ohse,
which is similar to cron, but safer. Here is an usage example::

    >>> from uschedule import Scheduler
    >>> s = Scheduler("mydir")
    >>> s.schedule("ls","*-*-* 08:05:40")

.. _uschedule: http://www.ohse.de/uwe/uschedule.html

:author: Andres J. Diaz <ajdiaz@connectical.com>
:date:   2010-08-19
"""

import pytai, shutil, os

DEFAULT_EPOCH = 4611686018427387914L # 1972-01-01 for TAI dates.
FLAG_NULL1 = 0x01
FLAG_NULL2 = 0x02


def parse_spec(date):
    date = date.replace("\t"," ").strip()
    wd = 0
    ret = ""
    try:
        weekday, date, time = date.split(" ")
        wd = parse_weekday(weekday)
        if wd != 0 and wd != 127:
            ret += "W%d" % wd
    except ValueError:
        date, time = date.split(" ")

    ret += parse_stamp(date, "-", [ "Y", "M", "D" ],
            lambda (x,y):list.insert(x,0,y), [ 2100, 12, 31 ])


    ret += parse_stamp(time, ":", [ "h", "m", "s" ],
            lambda (x,y):list.insert(x,0,y), [ 23, 59, 59 ])

    return ret


def parse_weekday(weekday):
    wd = 0

    for opt in weekday.split(","):
       if opt[0:3] == "Sun":
           wd|=1
       elif opt[0:3] == "Mon":
           wd|=2
       elif opt[0:3] == "Tue":
           wd|=4
       elif opt[0:3] == "Wed":
           wd|=8
       elif opt[0:3] == "Thu":
           wd|=16
       elif opt[0:3] == "Fri":
           wd|=32
       elif opt[0:3] == "Sat":
           wd|=64
       else:
           raise ValueError("Bad weekday")

    return wd

def is_complete_spec(spec):
    try:
        s = parse_spec(spec)
        if "W" in s: return False
        if "Y" in s and "M" in s and "D" in s and \
                "h" in s and "m" in s and "s" in s:
            return True
        else:
            return False
    except:
        return False

def parse_stamp(date, sep, stamp, insertfn, max_val):
    split = date.replace("+","/").split(sep)
    field = len(split)
    ret = ""

    if field != 3:
        insertfn((split,"-"))

    for i in range(len(split)):
       try:
           if split[i] == "-" or split[i] == "*":
               continue
           if  "/" in split[i]:
               init, step = map(int, split[i].split("/"))
               init -= 1
               ret += "%c%d" % (stamp[i], init)
               for j in range((init+step), max_val[i], step):
                    ret += ",%d" % j
           else:
               ret += "%c%s" % (stamp[i], split[i])

       except ValueError:
            raise ValueError("Syntax error in time spec")

    return ret



class Scheduler(object):
    """  """

    def __init__(self, directory):
        self.directory = directory

    def add_command(self, command):
        shutil.copy(command, os.path.join(self.directory, "commands"))

    def schedule(self, command, timespec, count=0, every=0, comment="",
            from_date="", to_date="", late=3600, flags=0):
        timespec = parse_spec(timespec)
        tailast = pytai.tai()
        tailast.from_tai64n_ext("0")
        sflags = ""

        if flags & FLAG_NULL1:
            sflags += "null1"
        if flags & FLAG_NULL2:
            if len(sflags):
                sflags += ",null2"
            else:
                sflags += "null2"

        shutil.copy(
                os.path.join(self.directory, "commands/" + command),
                os.path.join(self.directory,
                    "@%s:%s:%d:%d:%s:%s:%s:%s:%s:%d" % (
                        tailast.to_tai64n_ext()[0:16], command, late, count,
                    timespec, comment, sflags, from_date, to_date, every)) )
               
if __name__ == "__main__":
    import sys

    s = Scheduler(sys.argv[1])
    s.schedule("1", sys.argv[2])