root / pykota / trunk / FAQ @ 2095

PyKota's FAQ :

  # $Id$
  
  * How can I diagnose the problem when something goes wrong ?
  
    Put "LogLevel debug2" in cupsd.conf (usually in /etc/cups/).
    Then put "logger: stderr", "debug: yes" and 
    "crashrecipient: youremailaddress" in /etc/pykota/pykota.conf.
    Finally restart CUPS.
    CUPS' error_log file will now contain many informations which
    will help diagnose your problem. You will receive failure
    notices by email, and you can send all this to us for
    diagnostic. Please send complete files and not some sparse
    parts of them. Also please send the log files as gzipped 
    (or bzip2-ed) attachments.
    
    For LPRng, better to put "logger: system" in pykota.conf so
    that all debug messages for PyKota will go to syslog's
    destination for the LPR syslog facility.
    
    IMPORTANT : please don't send log files to the mailing list
    unless they are very small of unless someone asked for this.
  
  * Some commands tell me I'm not allowed to use them, why ?
  
    Some commands refuse to work when launched as a normal user,
    and output a message saying "You're not allowed to use this
    command." This is because their use is reserved to PyKota
    Administrators. A PyKota Administrator is any user allowed
    to read the pykotadmin.conf file. Beware : any user who can
    read this file can connect to PyKota's database in read+write
    mode, so take care of not opening a breach when modifying
    the permissions on this file.
    
  * What permissions should I use on PyKota's configuration files ?   
  
    It's probably best to do this :
    
        $ chown pykota.pykota pykota.conf pykotadmin.conf
        $ chmod 640 pykota.conf
        $ chmod 600 pykotadmin.conf
        
    Then the user 'pykota' will be the only PyKota Administrator    
    (with user 'root' of course), but all members of the 'pykota'
    group will be allowed to use unrestricted PyKota commands
    like repykota.
    
  * How can I limit my users to N pages per day (month/year) ?
  
    The easiest way to do this is to create their print quota
    entries using something like :
        
      $ edpykota --add -S 30 -H 30 user1 user2 user3 ...
        
      this would limit users to 30 pages on each printer.
        
    Then in a crontab launched every day (month/year) you could    
    do :
    
      00 23 * * * /usr/bin/edpykota --reset 
        
      this would reset every user's page counter to 0 on each printer
      at 23h00 every day. 
  
  * How can I tell PyKota to allow some users to print without limitation ?
   
    Just create these users' print quota entries this way :
    
      $ edpykota --add --limitby quota --noquota user1 user2 ...
  
      This would effectively put these users in "no limit" mode on
      each printer. If you want to do this only on some printers, just
      use the --printer command line argument as well. See
      edpykota's documentation for details.
      
    Another way to do this when you limit your users by balance, is  
    to set an overcharging factor of zero for every user you want to
    print with no limitation :
    
      $ edpykota --add --limitby balance --overcharge 0 user1 user2 ...
  
  * Nothing prints when my printer is in PowerSave mode, what
    can I do ?
    
    This happens if you use hardware accounting with SNMP, because
    some (all ?) printers don't say they are idle when they are
    in PowerSave mode.
    For now your best bet is to disable PowerSave mode in
    your printer. In the future, PyKota will modified to
    handle such problems.
  
  * I've installed all correctly, I've created users
    and printers, but when printing nothing works. 
    What is the problem ?
    The most probable cause for this is that you didn't
    adapt /etc/pykota/pykota.conf to your own configuration.
    The file installed by default is just an example, you
    have to modify it. See the rest of this document to
    learn how to really diagnose what went wrong.
    
  * I've downloaded PyKota from CVS using a Windows based CVS  
    tool, and now nothing works at all. What happened ?
    
    Some (all?) Windows based CVS tools translate *nix line endings
    (character Line Feed, ASCII code 10) into Windows line endings
    (character Carriage Return, ASCII code 13, followed with 
    character Line Feed). This breaks the software which has
    to run under *nix compatible systems. Set correct options
    in your CVS software so that it doesn't do any translation,
    or use an Unix-like version of CVS, download again and
    reinstall the software. It should work.
    
  * Why doesn't CUPS under Debian Woody automatically
    detects PyKota managed devices ?
    
    The CUPS version in Debian Woody is 1.1.14 which is a bit
    too old. To use PyKota with this version, just install
    your printers as usual in CUPS web interface, and ensure
    they work fine, then save your changes, and modify
    /etc/cups/printers.conf manually as explained in
    PyKota's toplevel README file. Finally restart CUPS,
    and your printers should be managed by PyKota.
    Another solution is to install a newer CUPS release.
    
  * Is print accounting ever exact ?
  
    No. Print accounting is **never** exact, because it depends
    on external factors like the presence of paper in the printer,
    the quantity of remaining ink in the print cartridge, paper
    jams, etc... All these things are very difficult to account
    for correctly, and no print accounting package deals with
    these artefacts correctly in all situations.
    We are however confident that PyKota is one of the more
    exact print accounting software, because by default it
    asks the printers for how many pages they have really printed.
    
  * Can PyKota account for ink usage ?  
  
    No. Actually PyKota doesn't account for ink usage, but this
    may come in a future release. PyKota only accounts for pages
    printed and/or money spent.  If ink accounting is a necessity
    for you, PrintBill is recommended instead of PyKota. PrintBill
    allows you to bill differently per color, and to bill depending
    on the percent of the ink covered part of the pages.
    
  * What is a 'dumb printer' ?
  
    In PyKota, the term 'dumb printer' defines a printer which doesn't 
    natively understand PostScript, PCL5 (up to), PCLXL (aka PCL6), PDF 
    or ESC/P2 and doesn't have an internal page counter, and for which 
    you don't know how to compute a job's size in number of pages by 
    analyzing its content. 
    Any printer which is not a 'dumb printer' according to the above 
    definition is supported by PyKota. 

  * How can I make PyKota work with my non-postscript printer under 
    CUPS ?  
  
    From version 1.16alpha7, PyKota includes a CUPS backend which
    allows you to use any type of printer and any driver, provided
    your printer is not a 'dumb printer' (see above).
    
  * How can I use my 'dumb printer' with CUPS and PyKota.  
  
    You have to use a software accounter directive, and 
    create a script which understands your printer's
    Page Description Language.
    
    PyKota natively understands DSC compliant PostScript, 
    PCL3, PCL4, PCL5, PCLXL (aka PCL6), PDF and ESC/P2. Support 
    for Binary PostScript is done through GhostScript. More PDLs
    will be added in the future.  
    However you can always plug your own PDL analyzer in PyKota.
          
  * I've got a great number of users. How can I automatically
    set an initial print quota for them on first print ?
    
    You have to define an external policy for unknown users,
    to automatically add them to the Print Quota database.
    The sample configuration file contains examples to do this.
    
  * What does the --prototype command line option to edpykota do ?
  
    This option currently (v1.20) only copies the soft and hard
    page limits from a template user to other users. This option
    needs to be updated to new PyKota functionnalities, because it
    currently lacks.
    
  * How can I share print quota between some printers only (not all) ?   
  
    To do this you have to put the printers into a printers group, and
    set quota on the printer group, instead of (or in addition to)
    the printers themselves.
    
  * What is a printer group ?
  
     A printer group is exactly like a normal printer, but is
     unknown by the printing system. You can use printer groups
     to share print quota between printers.
    
  * How can I create a printer group ?   
  
    Just use pkprinters, like for normal printers, then create
    quota entries for users or users groups on it using the
    edpykota command
 
  * How can I put a printer into a printer group ?
  
    Use the pkprinters command to do this.
    
      $ pkprinters --help
      
    Will print the complete help and tell you how to do.
    
  * How quota checking and update is done with printer groups ?   
  
    Print accounting and quota checking is done for a printer and
    all the printers groups it belongs to, recursively.
    If quota is reached on ANY of these printers for the current user,
    printing is denied.
    
  * Is this feature robust ?
  
    It should be. However, beware of integrity problems. LDAP has no 
    sense of database integrity, and PostgreSQL constraints have not 
    yet been fully implemented. The code actually *tries* to forbid 
    circular printers groups, but if you create printer groups with
    another tool (e.g. psql or gq), then you are mostly on you 
    own to not create infinite loops.
    
  * How is computed the job's price ?  
  
    A job's price is computed with this formula :
    
      SUM((NbPages * PricePerPage) + PricePerJob)
      
    For current printer and all the printers groups it is 
    a member of, if any, recursively.
    This may be difficult to grasp, but offers unprecedented
    flexibility.

  * My question isn't answered there, can you help ?  
  
    Sure. Ask your question to the mailing list. If this is a
    frequently asked question, or if your problem is on the contrary
    very specific, it will probably be added to this document.
    
    You can also ask questions by IRC :
    
        /server irc.freenode.net
        /join #pykota
        
Send any new questions to Jerome Alet - <alet@librelogiciel.com>