root / pykota / trunk / bin / cupspykota @ 1177

#! /usr/bin/env python
# -*- coding: ISO-8859-15 -*-

# CUPSPyKota accounting backend
#
# PyKota - Print Quotas for CUPS and LPRng
#
# (c) 2003 Jerome Alet <alet@librelogiciel.com>
# This program 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.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
#
# $Id$
#
# $Log$
# Revision 1.1  2003/11/08 16:05:31  jalet
# CUPS backend added for people to experiment.
#
#
#

import sys
import os
import time

from pykota.tool import PyKotaTool, PyKotaToolError
from pykota.config import PyKotaConfigError
from pykota.storage import PyKotaStorageError
from pykota.accounter import openAccounter, PyKotaAccounterError
from pykota.requester import openRequester, PyKotaRequesterError

class PyKotaBackend(PyKotaTool) :    
    """Class for the PyKota backend."""
    def __init__(self) :
        PyKotaTool.__init__(self)
        (self.printingsystem, \
         self.printerhostname, \
         self.printername, \
         self.username, \
         self.jobid, \
         self.inputfile, \
         self.copies, \
         self.title, \
         self.options, \
         self.originalbackend) = self.extractCUPSInfo()
        self.accounter = openAccounter(self)
    
    def extractCUPSInfo(self) :    
        """Returns a tuple (printingsystem, printerhostname, printername, username, jobid, filename, title, options, backend).
        
           Returns (None, None, None, None, None, None, None, None, None, None) if no printing system is recognized.
        """
        # Try to detect CUPS
        if os.environ.has_key("CUPS_SERVERROOT") and os.path.isdir(os.environ.get("CUPS_SERVERROOT", "")) :
            if len(sys.argv) == 7 :
                inputfile = sys.argv[6]
            else :    
                inputfile = None
                
            # the DEVICE_URI environment variable's value is 
            # prefixed with "cupspykota:" otherwise we wouldn't
            # be called. We have to remove this from the environment 
            # before launching the real backend.
            fulldevice_uri = os.environ.get("DEVICE_URI", "")
            device_uri = fulldevice_uri[len("cupspykota:"):]
            os.environ["DEVICE_URI"] = device_uri
            # TODO : check this for more complex urls than ipp://myprinter.dot.com:631/printers/lp
            try :
                (backend, destination) = device_uri.split(":", 1) 
            except ValueError :    
                raise PyKotaToolError, "Invalid DEVICE_URI : %s\n" % device_uri
            while destination.startswith("/") :
                destination = destination[1:]
            printerhostname = destination.split("/")[0].split(":")[0]
            return ("CUPS", \
                    printerhostname, \
                    os.environ.get("PRINTER"), \
                    sys.argv[2].strip(), \
                    sys.argv[1].strip(), \
                    inputfile, \
                    int(sys.argv[4].strip()), \
                    sys.argv[3], \
                    sys.argv[5], \
                    backend)
        else :    
            self.logger.log_message(_("Printing system unknown, args=%s") % " ".join(sys.argv), "warn")
            return (None, None, None, None, None, None, None, None, None, None)   # Unknown printing system          
        
def format_commandline(prt, usr, cmdline) :            
    """Passes printer and user names on the command line."""
    printer = prt.Name
    user = usr.Name
    # we don't want the external command's standard 
    # output to break the print job's data, but we
    # want to keep its standard error
    return "%s >/dev/null" % (cmdline % locals())

def main(thebackend) :    
    """Do it, and do it right !"""
    #
    # Get the last page counter and last username from the Quota Storage backend
    printer = thebackend.storage.getPrinter(thebackend.printername)
    if not printer.Exists :
        # The printer is unknown from the Quota Storage perspective
        # we let the job pass through, but log a warning message
        thebackend.logger.log_message(_("Printer %s not registered in the PyKota system") % thebackend.printername, "warn")
    else :    
        for dummy in range(2) :
            user = thebackend.storage.getUser(thebackend.username)
            if user.Exists :
                break
            else :    
                # The user is unknown from the Quota Storage perspective
                # Depending on the default policy for this printer, we
                # either let the job pass through or reject it, but we
                # log a message in any case.
                (policy, args) = thebackend.config.getPrinterPolicy(thebackend.printername)
                if policy == "ALLOW" :
                    action = "POLICY_ALLOW"
                elif policy == "EXTERNAL" :    
                    commandline = format_commandline(printer, user, args)
                    thebackend.logger.log_message(_("User %s not registered in the PyKota system, applying external policy (%s) for printer %s") % (thebackend.username, commandline, thebackend.printername), "info")
                    if os.system(commandline) :
                        # if an error occured, we die without error,
                        # so that the job doesn't stop the print queue.
                        thebackend.logger.log_message(_("External policy %s for printer %s produced an error. Job rejected. Please check PyKota's configuration files.") % (commandline, thebackend.printername), "error")
                        return 0
                    else :    
                        # here we try a second time, because the goal
                        # of the external action was to add the user
                        # in the database.
                        continue 
                else :    
                    action = "POLICY_DENY"
                thebackend.logger.log_message(_("User %s not registered in the PyKota system, applying default policy (%s) for printer %s") % (thebackend.username, action, thebackend.printername), "warn")
                if action == "POLICY_DENY" :
                    # if not allowed to print then die, else proceed.
                    # we die without error, so that the job doesn't 
                    # stop the print queue.
                    return 0
                # when we get there, the printer policy allows the job to pass 
                break    
                    
        # if user exists, do accounting
        if user.Exists :
            # Is the current user allowed to print at all ?
            action = thebackend.warnUserPQuota(thebackend.storage.getUserPQuota(user, printer))
        elif policy == "EXTERNAL" :                
            # if the extenal policy produced no error, but the 
            # user still doesn't exist, we die without error,
            # so that the job doesn't stop the print queue.
            thebackend.logger.log_message(_("External policy %s for printer %s couldn't add user %s. Job rejected.") % (commandline, thebackend.printername, thebackend.username), "error")
            return 0
        
    MAXTRIES = 12    # maximum number of tries to get the printer's internal page counter
    TIMETOSLEEP = 10 # number of seconds to sleep between two tries to get the printer's internal page counter
    requester = openRequester(thebackend.config, thebackend.printername)
    def getPPC(requester, backend) :
        for i in range(MAXTRIES) :
            try :
                counterbeforejob = requester.getPrinterPageCounter(backend.printerhostname)
            except PyKotaRequesterError, msg :
                # can't get actual page counter, assume printer is off or warming up
                # log the message anyway.
                backend.logger.log_message("%s" % msg, "warn")
                counterbeforejob = None
            else :    
                # printer answered, it is on so we can exit the loop
                break
            time.sleep(TIMETOSLEEP)    
        return counterbeforejob    
        
    if action not in ["ALLOW", "WARN"] :    
        # if not allowed to print then die, else proceed.
        # we die without error, so that the job doesn't 
        # stop the print queue.
        retcode = 0
    else :
        # pass the job untouched to the underlying layer
        # but get printer page counter before and after
        # print job is submitted to the hardware.
        
        # get page counter before job
        before = getPPC(requester, thebackend)
        
        # executes backend
        # TODO : use correct original backend.
        realbackend = os.path.join(os.path.split(sys.argv[0])[0], thebackend.originalbackend)
        retcode = os.spawnve(os.P_WAIT, realbackend, [os.environ["DEVICE_URI"]] + sys.argv[1:], os.environ)
    
    # get page counter after job
    after = getPPC(requester, thebackend)
    
    # Computes the last job size as the difference between internal page
    # counter in the printer and last page counter taken from the Quota
    # Storage database for this particular printer
    try :
        jobsize = (after - before)    
    except :    
        jobsize = 0
        
    # update the quota for the current user on this printer 
    if printer.Exists :
        if jobsize :
            userquota = thebackend.storage.getUserPQuota(user, printer)
            if userquota.Exists :
                userquota.increasePagesUsage(jobsize)
        
        # adds the current job to history    
        printer.addJobToHistory(thebackend.jobid, user, after, action, jobsize)
    
    return retcode

if __name__ == "__main__" :    
    # This is a CUPS backend, we should act and die like a CUPS backend
    if len(sys.argv) == 1 :
        print 'direct cupspykota "PyKota" "Print Quota and Accounting Backend"' 
        retcode = 0
    elif len(sys.argv) not in (6, 7) :    
        sys.stderr.write("ERROR: %s job-id user title copies options [file]\n" % sys.argv[0])
        retcode = 1
    else :    
        try :
            # Initializes the backend
            kotabackend = PyKotaBackend()    
            retcode = main(kotabackend)
        except (PyKotaToolError, PyKotaConfigError, PyKotaStorageError, PyKotaAccounterError, AttributeError, KeyError, IndexError, ValueError, TypeError, IOError), msg :
            sys.stderr.write("ERROR : cupspykota backend failed (%s)\n" % msg)
            sys.stderr.flush()
            retcode = 1
        
        try :
            kotabackend.storage.close()
        except (TypeError, NameError, AttributeError) :    
            pass
        
    sys.exit(retcode)