[322] in athena10
Re: Cluster printing in the wrapper
daemon@ATHENA.MIT.EDU (Kenneth Charles Arnold)
Thu Jul 17 23:36:30 2008
Message-ID: <48800F8C.4090104@mit.edu>
Date: Thu, 17 Jul 2008 23:35:40 -0400
From: Kenneth Charles Arnold <kcarnold@MIT.EDU>
MIME-Version: 1.0
To: Greg Hudson <ghudson@mit.edu>
CC: athena10@mit.edu
In-Reply-To: <1215749690.18347.246.camel@error-messages.mit.edu>
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So I did. Let's try this again.
Though I noticed that there's a direct Python hesiod interface that
pyhesiodfs uses. The script should probably use that. Not to mention
falling back to the $PRINTER environment variable if it exists.
And line 62 looks like a copy-paste bug...?
-Ken
Greg Hudson wrote:
> Uh, you attached the lpr.debathena-orig binary by mistake?
>
>
>
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Content-Type: text/plain;
name="lpr"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="lpr"
#!/usr/bin/python
# lpr.debathena
#
# also lp.debathena, lpq.debathena, and lprm.debathena
#
# Wrapper script that intelligently determines whether a command was
# intended for should go to CUPS or LPRng and sends it off in the
# right direction
import getopt
import os
import sys
from subprocess import call, PIPE, Popen
opts = {
'cancel': 'aD:Eh:P:U:u:',
'lp': 'ABcd:D:Ef:Gh:H:i:mn:o:pP:q:rsS:t:T:U:wX:y:',
'lpq': 'aAD:Eh:lLP:st:U:V',
'lpr': '#:1:2:3:4:AbBC:D:EF:GhH:i:J:kK:lmo:pP:qrR:sT:U:Vw:X:YZ:',
'lprm': 'aAD:Eh:lLP:st:U:V'
}
def error(code, message):
"""Exit out with an error
"""
sys.stderr.write(message)
sys.exit(code)
def run(name, command, rargs):
"""Given a path to a command and the rest of the arguments, exec it
"""
os.execv(command, [name] + rargs)
def returnCode(*command):
"""Get the return code of a command and throw away the output
"""
return call(command, stdout=PIPE, stderr=PIPE)
def cupsQueueExists(queue):
"""Test if queue name exists as a CUPS queue
"""
return returnCode('/usr/bin/lpq.debathena-orig', '-P%s' % queue) == 0
def lprngQueueExists(queue):
"""Test if queue name exists as an LPRng queue
"""
return returnCode('/usr/bin/hesinfo', queue, 'pcap') == 0
def useCups(command, queue, args):
"""If queue exists as a CUPS queue, pass the command and arguments on to the
CUPS versions of the command
"""
if queue == None or cupsQueueExists(queue) or not lprngQueueExists(queue):
new_command = '/usr/bin/%s.debathena-orig' % command
run(command, new_command, args)
def useLprng(command, queue, args):
"""If queue exists as an LPRng queue, pass the command and arguments on to
the LPRng versions of the command
"""
if queue == None or lprngQueueExists(queue) or not lprngQueueExists(queue):
new_command = '/usr/bin/mit-%s' % command
run(command, new_command, args)
def getClusterQueue():
hostname = os.uname()[1]
raw_cluster_info = Popen(['/usr/bin/hesinfo', hostname, 'cluster'],
stdout=PIPE).communicate()[0].splitlines()
cluster_info = dict(line.split(' ', 1) for line in raw_cluster_info)
return cluster_info.get('lpr', None)
def getPrintQueue(command, args):
"""Given argv, extract the printer name, using knowledge of the possible
command line options for both the CUPS and LPRng versions of the command
that this script was called as.
"""
try:
# Get the set of options that correspond to the command that this
# script was invoked as
cmd_opts = opts[command]
options, args = getopt.gnu_getopt(args, cmd_opts)
for o, a in options:
if o == '-P':
return a
if command == 'cancel' and len(args) > 0:
return args[0]
return getClusterQueue()
# This script was invoked with argv[0] set to something it doesn't know
# about
except KeyError:
error(1, """
Error: this script was called as %s, when it must be called as
one of lpr, lpq, lprm, lp, or cancel
""" % command)
if __name__ == '__main__':
# Remove the command name from the arguments when we extract it
command = os.path.basename(sys.argv.pop(0))
queue = getPrintQueue(command, sys.argv)
# Figure out whether to prefer LPRng or CUPS. If we can't decide based on
# the config file, then we're going with CUPS
try:
# Ok, yeah, the lower might be going a little overboard, but I don't
# like giving users room to screw things up :)
preference = open('/etc/debathena-printing.conf').read().\
strip().lower()
except IOError:
preference = 'cups'
fns = {'cups': [useCups, useLprng],
'lprng': [useLprng, useCups]}
fn_args = [command, queue, sys.argv]
for fn in fns[preference]:
fn(*fn_args)
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