A routing queue is similar in concept to a load balance queue in that it transfers a job to a (different) print queue, but the job destination is chosen at the time the job is submitted to the queue rather than at the time the job is removed from the queue. A routing queue can modify the job control file, multiple copies of the same job can be sent to the same or different printers, and the job can be held, rejected, or processed immediately.
Edit the printcap file so it have the contents indicated below, create the /tmp/lp2 and /tmp/lp3 files with 0777 permissions. Create the /tmp/router.script with the contents indicated below, and give it 0755 (executable) permissions. Use checkpc -f to check the printcap, and then use lpc reread to restart the lpd server.
# printcap lp:force_localhost lp:server :lp=/dev/null :sd=/var/spool/lpd/%P :router=/tmp/router.script lp2:force_localhost lp2:server :sd=/var/spool/lpd/%P :lp=/tmp/lp2 lp3:force_localhost lp3:server :sd=/var/spool/lpd/%P :lp=/tmp/lp2 # /tmp/router.script #!/bin/sh /bin/cat <<EOF dest lp2 copies 2 Cred end dest lp3 end EOF exit 0
The router.script will write the routing information to its STDOUT. For our example, we want the destination lp2 to get two copies of the job and we want to change the class to red. Now run the following commands:
h4: {282} % lpc stop all
Printer: lp@h4
lp@h4.private: stopped
Printer: lp2@h4
lp2@h4.private: stopped
Printer: lp3@h4
lp3@h4.private: stopped
h4: {283} % lpq
Printer: lp@h4 (dest lp@localhost) (printing disabled) (dest lp2, lp3)
Queue: no printable jobs in queue
Printer: lp2@h4 (printing disabled)
Queue: no printable jobs in queue
Printer: lp3@h4 (printing disabled)
Queue: no printable jobs in queue
h4: {284} % lpr /tmp/hi
h4: {285} % lpq
Printer: lp@h4 (dest lp@localhost) (printing disabled) (dest lp2, lp3)
Queue: 1 printable job
Server: no server active
Rank Owner/ID Class Job Files Size Time
1 papowell@h4+235 A 235 /tmp/hi 3 16:14:22
- papowell@h4+235.1 ->lp2 <cpy 0/2>
- papowell@h4+235.2 ->lp3
Printer: lp2@h4 (printing disabled)
Queue: no printable jobs in queue
Printer: lp3@h4 (printing disabled)
Queue: no printable jobs in queue
The status reported for the spooled job indicates that the job is routed to lp2, and that two copies will be sent. The :destinations option in the printcap entry causes lpq to display the contents of the specified queues. Now execute the following commands:
h4: {286} % lpc start
Printer: lp@h4
lp@h4.private: started
h4: {287} % lpq
Printer: lp@h4 (dest lp@localhost) (destinations lp2, lp3)
Queue: no printable jobs in queue
Status: job 'papowell@h4+235' removed at 16:14:37.491
Printer: lp2@h4 (printing disabled)
Queue: 2 printable jobs
Server: no server active
Rank Owner/ID Class Job Files Size Time
1 papowell@h4+235.1C1 A 235 /tmp/hi 3 16:14:36
2 papowell@h4+235.1C2 A 236 /tmp/hi 3 16:14:37
Printer: lp3@h4 (printing disabled)
Queue: 1 printable job
Server: no server active
Rank Owner/ID Class Job Files Size Time
1 papowell@h4+235.2 A 237 /tmp/hi 3 16:14:37
h4: {288} % more /var/spool/lpd/lp2/cfA235*
Hh4.private
Ppapowell
J/tmp/hi
Cred
Lpapowell
Apapowell@h4+235.1C1
D2000-06-01-16:03:25.237
Qlp
N/tmp/hi
fdfA235h4.private
UdfA235h4.private
As you can see, two copies of the job has been transferred to lp2 and one to lp3, each with a different job number, If we examine the control file for the jobs in the lp2 spool queue, we will find that the C or class information has been changed to red.
For details about all of the capabilities of the routing filter, see Dynamic Routing. Here is a summary of the information that the routing filter can put into the routing file.
Route this job to queue. The queue@host form will transfer the job to the queue on the named host.
Send N copies of this job to the destination.
Set the job priority letter to C, where C is a single upper case letter.
Set the control file line starting with C to Cvalue.
The exit status of the routing filter controls how the job will be processed. If the exit code is JSUCC (0), then the job will be processed normally, JHOLD will hold the job until released, JREMOVE will remove the job, and so forth.