cpython/Demo/scripts/lpwatch.py

#! /usr/bin/env python

# Watch line printer queue(s).
# Intended for BSD 4.3 lpq.

import posix
import sys
import time
import string

DEF_PRINTER = 'psc'
DEF_DELAY = 10

def main():
    delay = DEF_DELAY # XXX Use getopt() later
    try:
        thisuser = posix.environ['LOGNAME']
    except:
        thisuser = posix.environ['USER']
    printers = sys.argv[1:]
    if printers:
        # Strip '-P' from printer names just in case
        # the user specified it...
        for i in range(len(printers)):
            if printers[i][:2] == '-P':
                printers[i] = printers[i][2:]
    else:
        if 'PRINTER' in posix.environ:
            printers = [posix.environ['PRINTER']]
        else:
            printers = [DEF_PRINTER]
    #
    clearhome = posix.popen('clear', 'r').read()
    #
    while 1:
        text = clearhome
        for name in printers:
            text = text + makestatus(name, thisuser) + '\n'
        print(text)
        time.sleep(delay)

def makestatus(name, thisuser):
    pipe = posix.popen('lpq -P' + name + ' 2>&1', 'r')
    lines = []
    users = {}
    aheadbytes = 0
    aheadjobs = 0
    userseen = 0
    totalbytes = 0
    totaljobs = 0
    while 1:
        line = pipe.readline()
        if not line: break
        fields = string.split(line)
        n = len(fields)
        if len(fields) >= 6 and fields[n-1] == 'bytes':
            rank = fields[0]
            user = fields[1]
            job = fields[2]
            files = fields[3:-2]
            bytes = eval(fields[n-2])
            if user == thisuser:
                userseen = 1
            elif not userseen:
                aheadbytes = aheadbytes + bytes
                aheadjobs = aheadjobs + 1
            totalbytes = totalbytes + bytes
            totaljobs = totaljobs + 1
            if user in users:
                ujobs, ubytes = users[user]
            else:
                ujobs, ubytes = 0, 0
            ujobs = ujobs + 1
            ubytes = ubytes + bytes
            users[user] = ujobs, ubytes
        else:
            if fields and fields[0] != 'Rank':
                line = string.strip(line)
                if line == 'no entries':
                    line = name + ': idle'
                elif line[-22:] == ' is ready and printing':
                    line = name
                lines.append(line)
    #
    if totaljobs:
        line = '%d K' % ((totalbytes+1023)//1024)
        if totaljobs != len(users):
            line = line + ' (%d jobs)' % totaljobs
        if len(users) == 1:
            line = line + ' for %s' % (list(users.keys())[0],)
        else:
            line = line + ' for %d users' % len(users)
            if userseen:
                if aheadjobs == 0:
                    line =  line + ' (%s first)' % thisuser
                else:
                    line = line + ' (%d K before %s)' % (
                                   (aheadbytes+1023)//1024, thisuser)
        lines.append(line)
    #
    sts = pipe.close()
    if sts:
        lines.append('lpq exit status %r' % (sts,))
    return string.joinfields(lines, ': ')

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        pass