NAME

ps-watcher - monitors various processes based on ps-like information.


SYNOPSIS

ps-watcher [options...] [--config] config-file


DESCRIPTION

Periodically a list of processes names via ps is obtained. A configuration file specifies a list of Perl regular-expression patterns to match the processes against. For each match, a Perl expression specified for that pattern is evaluated. The evaluated expression can refer to variables which are set by ps and pertain to the matched process(es), for example the amount memory consumed by the process, or the total elapsed time. Some other variables are set by the program, such as the number of times the process is running. If the Perl expression for a matched pattern evaluates true, then an action can be run such as killing the program, restarting it, or mailing an alert.

This program can be used to ensure a daemon hasn't died or ensure it is not running too many times. It might be used to determine when a process has consumed too many resources (for example due to a memory leak).

Depending on options specfied, this program can be run as a daemon, run once (which is suitable as a cron job), or run not as a daemon but still continuously (which may be handy in testing the program or your configuration).


OPTIONS

--help

Print a usage message on standard error and exit with a return code of 100.

--version

Print the version release on standard output and exit with a return code of 10.

[--config] configuration file

Specify configuration file. .

See CONFIGURATION FILE FORMAT below for information on the format of the configuration file and EXAMPLE CONFIGURATION for a complete example of a configuration file.

--log [log file]

Send or don't send error and debugging output to a log file. If option is given but no logfile is specified, then use STDERR. The default is no error log file. See also --syslog below.

--syslog | --nosyslog

Send or don't send error and debugging output to syslog. The default is to syslog error and debug output.

--daemon | --nodaemon

Run or don't as a daemon.

--ps-prog program

One can specify the command that gives ps information. By default, the command is /bin/ps.

--sleep interval in seconds

It is expected that one might want to run ps-watcher over and over again. In such instances one can specify the amount of time between iterations with this option.

If a negative number is specified the program is run only once.


CONFIGURATION FILE MODIFICATION AND SIGNAL HANDLING

Periodically ps-watcher checks to see if the configuration file that it was run against has changed. If so, the program rereads the configuration file.

More precisely, the checks are done after waking up from a slumber. If the sleep interval is long (or if you are impatient), you can probably force the program to wake up using a HUP signal.

At any time you can increase the level of debug output by sending a USR1 signal to the ps-watcher process. Similarly you can decrease the level of debug output by sending the process a USR2 signal.

It is recommended that you terminate ps-watcher via an INT, TERM, or QUIT signal.


CONFIGURATION FILE FORMAT

The format of a configuration file is a series of fully qualified filenames enclosed in square brackets followed by a number of parameter lines. Each parameter line has a parameter names followed by an ``equal'' sign and finally value. That is:

 # This is a comment line
 ; So is this.
 [process-pattern1]
  parameter1 = value1
  parameter2 = value2

 [process-pattern2]
  parameter1 = value3
  parameter2 = value4

Comments start with # or ; and take effect to the end of the line.

This should be familiar to those who have worked with text-readible Microsoft .INI files.

Note process patterns, (process-pattern1 and process-pattern2 above) must be unique. If there are times when you may want to refer to the same process, one can be creative to make these unique. e.g. cron and [c]ron which refer to the same process even though they appear to be different.

As quoted directly from the IniConf manual page:

Multiline or multivalued fields may also be defined ala UNIX ``here document'' syntax:

  Parameter=<<EOT
  value/line 1
  value/line 2
  EOT

You may use any string you want in place of ``EOT''. Note that what follows the ``<<`` and what appears at the end of the text must match exactly, including any trailing whitespace.

A description of parameters names, their meanings and potential values follows.

trigger

This parameter specifies the condition on which a process action is fired. The condition is evaluated with Perl eval() and should therefore return something which is equivalent to ``true'' in a Perl expression.

If no trigger is given in a section, true or 1 is assumed and the action is unconditionally triggered.

Example:

  # Fire if /usr/sbin/syslogd is not running.
  # Since the program matches against the command names not commands and
  # arguments something like: 
  #   ps -ef | grep /usr/sbin/syslogd
  # won't match the below.
  [(/usr/sbin/)?syslogd]
  trigger = $count != 1
occurs

This parameter specifies how many times an action should be performed on processes matching the section trigger. Acceptable values are ``every'' and ``first''. If this parameter is not specified, ``first'' is assumed.

Examples:

  []
  occurs = first
  action = echo "You have $count processes running"

  [.]
  trigger = $vsz > 1000
  occurs  = every
  action  = echo "Large program $command matches $ps_pat: $vsz KB"
action

This specifies the action when the trigger condition is evaluated to be true.

Example:

 action = /etc/init.d/market_loader.init restart


EXPANDED VARIABLES IN TRIGGER/ACTION CLAUSES

Any variables defined in the program can be used in pattern or action parameters. For example, $program can be used to refer to the name of this program ps-watcher.

The following variables can be used in either the pattern or action fields.

$action

A string containing the text of the action to run.

$ps_pat

The Perl regular expression specified in the beginning of the section.

$command

The command that matched $ps_pat.

The Perl regular expression specified in the beginning of the section.

$count

The number of times the pattern matched. Presumably the number of processes of this class running.

$trigger

A string containing the text of the trigger.

A list of variables specific to this program or fields commonly found in ps output is listed below followed by a description of the more common ones. See also ps for a more complete description of the meaning of the field.

 alarm blocked bsdstart bsdtime c caught 
cputime drs dsiz egid egroup eip esp etime euid euser f fgid 
fgroup flag flags fname fsgid fsgroup fsuid fsuser fuid fuser gid   
group ignored intpri lim longtname m_drs m_trs maj_flt majflt 
min_flt  minflt ni nice nwchan opri pagein pcpu pending pgid pgrp 
pmem ppid pri rgid rgroup rss rssize rsz ruid ruser s sess session 
sgi_p sgi_rss sgid sgroup sid sig sig_block sig_catch sig_ignore 
sig_pend sigcatch sigignore sigmask stackp start start_stack start_time 
stat state stime suid suser svgid svgroup svuid svuser sz time timeout 
tmout tname tpgid trs trss tsiz tt tty tty4 tty8 uid uid_hack uname 
user vsize vsz wchan comm

$ppid

The parent process id.

$stime

The start time of the process.

$etime

The end time of the process.

$pmem

The process memory.

$pcpu

The percent CPU utilization.

$tty

The controlling tty.

$szv

Virtual memory size of the process


OTHER THINGS IN TRIGGER CLAUSES

To make testing against elapsed time easier, a function elapse2sec() has been written to parse and convert elapsed time strings in the format dd-hh:mm:ss and a number of seconds.

Some constants for the number of seconds in a minute, hour, or day have also been defined. These are referred to as MINS, HOURS, and DAYS respectively and they have the expected definitions:

  use constant MINS   => 60;
  use constant HOURS  => 60*60;
  use constant DAYS   => HOURS * 24;

Here is an example of the use of elapsed2sec():

  # Which processes have been running for more than 3 hours?
  # Also note use of builtin-function elapsed2secs, variable $etime
  # and builtin-function HOURS
  []
    trigger = elapsed2secs('$etime') > 1*DAYS
    action  = echo "$command has been running more than 1 day ($etime)"
    occurs  = every

Please note the quotes around '$etime'.


EXAMPLE CONFIGURATION

 # Comments start with # or ; and go to the end of the line.

 # The format for each entry is in Microsoft .INI form:
 # [process-pattern]
 # trigger = perl-expression
 # action  = program-and-arguments-to-run

  [(/usr/sbin/)?cron$]
    trigger = $count != 1
    action  = echo "$trigger fired -- You have $count cron sessions."

  []
  trigger = $vsz > 10
  action  = echo "Looks like you have a big $command program: $vsz KB"

  [.]
    trigger = $pcpu > 70
    occurs  = every
    action  = <<EOT
     echo "$command used $pcpu% CPU" | /bin/mail root
     kill -TERM $pid
  EOT


SEE ALSO

See also ps(1) and syslogd.

Another cool program doing ps-like things is xps. Well okay, it's another program I distributed. It shows the process tree dynamically updated using X Motif and tries to display the output ``attractively'' but fast. You can the find the homepage at http://www.netwinder.org/~rocky/xps-home and it is available via anonymous FTP at ftp://ftp.netwinder.org/users/r/rocky/xps.tar.gz


AUTHOR

Rocky Bernstein (rocky@panix.com)


COPYRIGHT

  Copyright (C) 2000 Rocky Bernstein, email: rocky@panix.com.
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.