root / pykota / trunk / FAQ @ 1529

PyKota's FAQ :

  # $Id$
  
  * 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.
  
  * 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 
    understand PostScript 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 
    with 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 PostScript and PCL5,
    but PCL6 support is in the works, and 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 (v1.17) 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 diagnose the problem when something goes wrong ?
  
    Put "LogLevel debug2" in cupsd.conf (usually in /etc/cups/).
    Then put "logger: system" and "debug: yes" in 
    /etc/pykota/pykota.conf.
    Finally restart CUPS.
    CUPS' error_log file will now contain many informations which
    will help diagnose your problem. Also your syslog's output for 
    the LPR facility (usually /var/log/lpr.log) will contain 
    PyKota's debug messages, notably all database related queries
    and their result, be your database PostgreSQL or OpenLDAP.
    With these two files the problem can usually be diagnosed within
    minutes. Send them to the mailing list and wait for an answer.
    
  * 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>