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Created: Wed, May 22, 01:44

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	## $Id$
	## BibTaskEx: an example on how to write BibSched tasks.

	## This file is part of the CERN Document Server Software (CDSware).
	## Copyright (C) 2002 CERN.
	##
	## The CDSware is free software; you can redistribute it and/or
	## modify it under the terms of the GNU General Public License as
	## published by the Free Software Foundation; either version 2 of the
	## License, or (at your option) any later version.
	##
	## The CDSware is distributed in the hope that it will be useful, but
	## WITHOUT ANY WARRANTY; without even the implied warranty of
	## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	## General Public License for more details.
	##
	## You should have received a copy of the GNU General Public License
	## along with CDSware; if not, write to the Free Software Foundation, Inc.,
	## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

	## read config variables:
	#include "config.wml"
	#include "configbis.wml"

	## start Python:
	<protect>#!</protect><PYTHON>
	<protect>## $Id$
	<protect>## DO NOT EDIT THIS FILE! IT WAS AUTOMATICALLY GENERATED FROM CDSware WML SOURCES.</protect>

	## import interesting modules:
	pylibdir = "<LIBDIR>/python"

	## okay, rest of the Python code goes below
	#######

	__version__ = "$Id$"

	try:
	import sys
	sys.path.append('%s' % pylibdir)
	from cdsware.dbquery import run_sql
	import getopt
	import marshal
	import signal
	import string
	import sys
	import time
	except ImportError, e:
	print "Error: %s" % e
	import sys
	sys.exit(1)

	cfg_n_default = 30 # how many Fibonacci numbers to calculate if none submitted?

	def write_message(msg, stream=sys.stdout):
	"""Prints message and flush output stream (may be sys.stdout or sys.stderr). Useful for debugging stuff."""
	if stream == sys.stdout or stream == sys.stderr:
	stream.write(time.strftime("%Y-%m-%d %H:%M:%S --> ", time.localtime()))
	stream.write("%s\n" % msg)
	stream.flush()
	else:
	sys.stderr.write("Unknown stream %s. [must be sys.stdout or sys.stderr]\n" % stream)

	def task_sig_sleep(sig, frame):
	"""Signal handler for the 'sleep' signal sent by BibSched."""
	write_message("sleeping...")
	task_update_state("SLEEPING")
	signal.pause() # wait for wake-up signal

	def task_sig_wakeup(sig, frame):
	"""Signal handler for the 'wakeup' signal sent by BibSched."""
	write_message("continuing...")
	task_update_state("CONTINUING")

	def task_sig_stop(sig, frame):
	"""Signal handler for the 'stop' signal sent by BibSched."""
	write_message("stopping...")
	task_update_state("STOPPING")
	write_message("flushing cache or whatever...")
	time.sleep(3)
	write_message("closing tables or whatever...")
	time.sleep(1)
	write_message("stopped")
	task_update_state("STOPPED")
	sys.exit(0)

	def task_sig_suicide(sig, frame):
	"""Signal handler for the 'suicide' signal sent by BibSched."""
	write_message("suiciding myself now...")
	task_update_state("SUICIDING")
	write_message("suicided")
	task_update_state("SUICIDED")
	sys.exit(0)

	def task_sig_unknown(sig, frame):
	"""Signal handler for the other unknown signals sent by shell or user."""
	write_message("unknown signal %d ignored" % sig) # do nothing for other signals

	def fib(n):
	"""Returns Fibonacci number for 'n'."""
	out = 1
	if n >= 2:
	out = fib(n-2) + fib(n-1)
	return out

	def getpass(prompt = "Password: "):
	"""Prompts for a password without echoing it back to the screen"""
	import termios, sys
	fd = sys.stdin.fileno()
	old = termios.tcgetattr(fd)
	new = termios.tcgetattr(fd)
	new[3] = new[3] & ~termios.ECHO # lflags
	passwd = ""
	try:
	termios.tcsetattr(fd, termios.TCSADRAIN, new)
	passwd = raw_input(prompt)
	print
	finally:
	termios.tcsetattr(fd, termios.TCSADRAIN, old)
	return passwd

	def authenticate(user):
	"""Authenticates a user against the user database.
	NOTE: Access might be more complex in the future"""
	print "BibTaskEx Task Submission"
	print "========================="
	if user == "":
	print >> sys.stdout, "\rUsername: ",
	user = string.strip(string.lower(sys.stdin.readline()))
	else:
	print >> sys.stdout, "\rUsername:", user

	res = run_sql("select password from user where email=%s", (user,), 1)
	if res:
	row = res[0]
	password_db = row[0]
	if password_db != '':
	# authentication needed
	password_entered = getpass()
	if password_db == password_entered:
	return user
	else:
	print "Sorry, you seem to be unauthorized user. Exiting."
	sys.exit(1)
	else:
	# no authentication needed
	return user
	else:
	print "Sorry, %s seems to be unauthorized user. Exiting." % user
	sys.exit(1)

	def task_submit(options):
	"""Submits task to the BibSched task queue. This is what people will be invoking via command line."""
	## sanity check: remove eventual "task" option:
	if options.has_key("task"):
	del options["task"]
	## authenticate user:
	user = authenticate(options.get("user", ""))
	## submit task:
	task_id = run_sql("""INSERT INTO schTASKS (id,proc,user,state,date,arguments) VALUES (NULL,'bibtaskex',%s,'WAITING',NOW(),%s)""",
	(user, marshal.dumps(options)))
	## update task number:
	options["task"] = task_id
	run_sql("""UPDATE schTASKS SET arguments=%s WHERE id=%s""", (marshal.dumps(options),task_id))
	write_message("Task #%d submitted." % task_id)
	return task_id

	def task_update_progress(msg):
	"""Updates progress information in the BibSched task table."""
	global task_id
	return run_sql("UPDATE schTASKS SET progress=%s where id=%s", (msg, task_id))

	def task_update_state(val):
	"""Updates state information in the BibSched task table."""
	global task_id
	return run_sql("UPDATE schTASKS SET state=%s where id=%s", (val, task_id))

	def task_read_state(task_id):
	"""Read state information in the BibSched task table."""
	res = run_sql("SELECT state FROM schTASKS where id=%s", (task_id,), 1)
	try:
	out = res[0][0]
	except:
	out = 'UNKNOWN'
	return out

	def task_get_options(id):
	"""Returns options for the task 'id' read from the BibSched task queue table."""
	out = {}
	res = run_sql("SELECT arguments FROM schTASKS WHERE id=%s AND proc='bibtaskex'", (id,))
	try:
	out = marshal.loads(res[0][0])
	except:
	write_message("Error: BibTaskEx task %d does not seem to exist." % id)
	sys.exit(1)
	return out

	def task_run():
	"""Runs the task by fetching arguments from the BibSched task queue. This is what BibSched will be invoking via daemon call.
	The task prints Fibinacci numbers for up to NUM on the stdout, and some messages on stderr."""
	global task_id
	options = task_get_options(task_id) # get options from BibSched task table
	## check task id:
	if not options.has_key("task"):
	write_message("Error: The task #%d does not seem to be a BibTaskEx task." % task_id)
	return
	## check task state:
	task_state = task_read_state(task_id)
	if task_state != "WAITING":
	write_message("Error: The task #%d is %s. I expected WAITING." % (task_id, task_state))
	return
	## update task state:
	task_update_state("RUNNING")
	## initialize signal handler:
	signal.signal(signal.SIGUSR1, task_sig_sleep)
	signal.signal(signal.SIGTERM, task_sig_stop)
	signal.signal(signal.SIGABRT, task_sig_suicide)
	signal.signal(signal.SIGCONT, task_sig_wakeup)
	signal.signal(signal.SIGINT, task_sig_unknown)
	## run the task:
	if options.has_key("number"):
	n = options["number"]
	else:
	n = cfg_n_default
	if options.has_key("debug"):
	write_message("Dbg: printing %d Fibonacci numbers." % n)
	for i in range(0,n):
	if i > 0 and i % 4 == 0:
	write_message("Error: water in the CPU.", sys.stderr)
	elif i > 0 and i % 5 == 0:
	write_message("Error: floppy drive dropped on the floor.", sys.stderr)
	write_message("fib(%d)=%d" % (i, fib(i)))
	task_update_progress("Done %d out of %d." % (i,n))
	time.sleep(1)
	## we are done:
	task_update_progress("Done %d out of %d." % (n,n))
	task_update_state("DONE")
	return

	def usage(exitcode=1, msg=""):
	"""Prints usage info."""
	if msg:
	sys.stderr.write("Error: %s.\n" % msg)
	sys.stderr.write("Usage: %s [options]\n" % sys.argv[0])
	sys.stderr.write(" -n, --number=NUM\t Print Fibonacci numbers for up to NUM. [default=%d]\n" % cfg_n_default)
	sys.stderr.write(" -u, --user=USER \t\t User name to submit the task as, password needed.\n")
	sys.stderr.write(" -h, --help \t\t Print this help.\n")
	sys.stderr.write(" -V, --version \t\t Print version information.\n")
	sys.stderr.write(" -d, --debug \t\t Print debugging information.\n")
	sys.exit(exitcode)

	def main():
	"""Main function that analyzes command line input and calls whatever is appropriate.
	Useful for learning on how to write BibSched tasks."""
	global task_id
	## parse command line:
	if len(sys.argv) == 2 and sys.argv[1].isdigit():
	## A - run the task
	task_id = int(sys.argv[1])
	task_run()
	else:
	## B - submit the task
	options = {} # will hold command-line options
	try:
	opts, args = getopt.getopt(sys.argv[1:], "hVdn:u:", ["help", "version", "debug","number=","user="])
	except getopt.GetoptError, err:
	usage(1, err)
	try:
	for opt in opts:
	if opt[0] in ["-h", "--help"]:
	usage(0)
	elif opt[0] in ["-V", "--version"]:
	print __version__
	sys.exit(0)
	elif opt[0] in [ "-u", "--user"]:
	options["user"] = opt[1]
	elif opt[0] in ["-d", "--debug"]:
	options["debug"]=1
	elif opt[0] in ["-n", "--number"]:
	options["number"]=int(opt[1])
	except StandardError, e:
	usage(e)
	task_submit(options)
	return

	### okay, here we go:
	if __name__ == '__main__':
	main()

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