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.TH QER 8 

.SH NAME

qer, runq \- queue management for spooled files

.SH SYNOPSIS

.B qer

[

.B -q

.I subdir

]

[

.B -f

.I file

]

.I root tag reply args

.br

.B runq

[

.B -adsER

]

[

.B -f

.I file

]

[

.B -q

.I subdir

]

[

.B -l

.I load

]

[

.B -t

.I time

]

[

.B -r

.I nfiles

]

[

.B -n

.I nprocs

]

.I root cmd

.SH DESCRIPTION

.I Qer

creates a control and a data file in a queue directory.

The control file contents consist of the

.IR tag ,

.IR reply ,

and

.I args

separated by spaces.

The data file contains the standard input to

.IR qer .

The files are created in the directory

.IR root / subdir ,

where

.I subdir

is the argument to

.B -q

if present, else the contents of

.BR /dev/user .

The names of the control and data files differ only

in the first character which is `C' and `D' respectively.

.IR Mktemp (2)

is used to create the actual names of the control and

data file.

.P

Some commands, such as

.I fax

(see

.IR telco (4)),

must queue more files than just the data file.

Each

.I file

following a

.B \-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 is

starts with 'F', the second 'G', etc.

.P

.I Runq

processes the files queued by

.IR qer .

Without the

.B -a

option,

.I runq

processes all requests in the directory

.IR root / subdir ,

where

.I subdir

is the argument to

.B -q

if present, else the contents of

.BR /dev/user .

With the

.B -a

it processes all requests.

Each request is processed by executing the command

.I cmd

with the contents of the control file as its arguments,

the contents of the data file as its standard input, and

standard error appended to the error file

.BR E.XXXXXX .

.P

The action taken by

.I runq

depends on the return status of

.IR cmd .

If

.I cmd

returns a null status, the processing is assumed successful and the

control, data, and error files are removed.

If

.I cmd

returns an error status containing the word

.LR 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.

.I Runq

uses the

.I 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.

.P

To avoid reprocessing files too often, the following algorithm 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 

.B -E

flag causes all files to be reprocessed regardless of

the file times.

.P

The

.B -R

flag instructs

.I runq

never to give up on a failed queue job, instead leaving

it in the queue to be retried.

.P

The

.B -d

option causes debugging output on standard error

describing the progress through the queues.

.P

The

.B -t

flags specifies the number of hours

that retries will continue after a send

failure.  The default is 48 hours.

.P

The

.BR -r

flag limits the number of files that are processed in a single pass of a queue.

.I 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,

.I runq

exits without making progress.  This flag forces

.I runq

to process the directory in chunks, allowing the queue to

be drained incrementally.  It is most useful in combination with the

.I -q

flag.

.P

The

.BR -s ,

.BR -n ,

and

.B -l

flags are only meaningful with the

.B -a

flag.  They control amount of parallelism that

is used when sweeping all of the queues.  The argument following the

.B -n

flag specifies the number of queues that are swept

in parallel; the default is 50.  The argument following the

.B -l

flag specifies the total number of queues that are being swept.

By default, there is no limit.  The number of active sweeps

is cumulative over all active executions of

.IR runq .

The

.B -s

flag forces each queue directory to be processed by exactly

one instance of

.IR runq .

This is useful on systems that connect to slow

external systems and prevents all the queue sweeps from

piling up trying to process a few slow systems.

.PP

.I Runq

is often called from

.IR cron (8)

by an entry such as

.IP

.EX

0,10,20,30,40,50 * * * * kremvax

        runq -a /mail/queue /mail/lib/remotemail

.EE

.LP

The entry must be a single line; it is folded here only so it fits on the page.

.SH FILES

.TF \fIroot\fP/\fIuser\fP/[F-Z].XXXXXX

.TP

.B \fIroot\fP/\fIuser\fP

queue directory for

.I user

.TP

.B \fIroot\fP/\fIuser\fP/D.XXXXXX

data file

.TP

.B \fIroot\fP/\fIuser\fP/C.XXXXXX

control file

.TP

.B \fIroot\fP/\fIuser\fP/E.XXXXXX

error file

.TP

.B \fIroot\fP/\fIuser\fP/[F-Z].XXXXXX

secondary data files

.SH SOURCE

.B /sys/src/cmd/upas/q

.SH "SEE ALSO"

.IR mail (1)