QER(8) QER(8)
NAME
qer, runq - queue management for spooled files
SYNOPSIS
qer [ -q subdir ] [ -f file ] root tag reply args
runq [ -adER ] [ -f file ] [ -q subdir ] [ -t time ] [ -r
nfiles ] [ -n njobs ] root cmd
DESCRIPTION
Qer creates a control and a data file in a queue directory.
The control file contents consist of the tag, reply, and
args separated by spaces. The data file contains the stan-
dard input to qer. The files are created in the directory
root/subdi The names of the control and data files differ
only in the first character which is `C' and `D' respec-
tively. Mktemp(2) is used to create the actual names of the
control and data file.
Some commands, such as fax (see telco(4)), must queue more
files than just the data file. Each file following a -f
flag is copied into the queue directory. The names of the
copies differ from the name of the data file only in the
first character. The first one starts with 'F', the second
'G', etc.
Qer takes the following arguments:
-q subdir
Specifies the queue subdirectory to use. If unspeci-
fied, the contents of /dev/user are used.
-f file
Specifies the files to copy into the queue directory,
in the manner described above.
Runq processes the files queued by qer. Runq processes all
requests in the directory root/subdir, where subdir is the
argument to -q if present, else the contents of /dev/user.
Each request is processed by executing the command cmd with
the contents of the control file as its arguments, the con-
tents of the data file as its standard input, and standard
error appended to the error file E.XXXXXX.
The action taken by runq depends on the return status of
cmd. If cmd returns a null status, the processing is assumed
successful and the control, data, and error files are
removed. If cmd returns an error status containing the word
`Retry', the files are left to be reprocessed at a later
time. For any other status, an error message is mailed to
the requester and the files are removed. Runq uses the
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QER(8) QER(8)
reply field in the control file as a mail address to which
to send an error notification. The notification contains
the contents of the control file to identify the failed
request.
To avoid reprocessing files too often, the following algo-
rithm is used: a data file younger than one hour will not be
processed if its error file exists and was last modified
within the preceding 10 minutes. A data file older than one
hour will not be processed if its error file exists and was
last modified within the preceding hour.
The following flags are accepted by runq:
-a Causes runq to process all user directories in
sequence, instead of only the directory of the current
user.
-E Causes all files to be reprocessed regardless of the
file times.
-R Instructs runq never to give up on a failed queue job,
instead leaving it in the queue to be retried.
-d Causes debugging output on standard error describing
the progress through the queues.
-t Specifies the number of hours that retries will con-
tinue after a send failure. The default is 48 hours.
-r Limits the number of files that are processed in a sin-
gle pass of a queue. Runq accumulates the entire
directory containing a queue before processing any
files. When a queue contains many files and the system
does not have enough memory, runq exits without making
progress. This flag forces runq to process the direc-
tory in chunks, allowing the queue to be drained incre-
mentally. It is most useful in combination with the -q
flag.
-n Specifies the number of queued jobs that are processed
in parallel from the queue; the default is 1. This is
useful for a large queue to be processed with a bounded
amount of parallelism.
Runq is often called from cron(8) by an entry such as
0,10,20,30,40,50 * * * * kremvax
/bin/upas/runq -a /mail/queue /mail/lib/remotemail
The entry must be a single line; it is folded here only so
it fits on the page.
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QER(8) QER(8)
FILES
root/user queue directory for user
root/user/D.XXXXXX data file
root/user/C.XXXXXX control file
root/user/E.XXXXXX error file
root/user/[F-Z].XXXXXX secondary data files
SOURCE
/sys/src/cmd/upas/q
SEE ALSO
mail(1)
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