NAME

taskqueuectl - Simple program for querying and manipulating a cPanel::TaskQueue

SYNOPSIS

    $ taskqueuectl list verbose

    $ taskqueuectl queue 'command arg1 arg2' 'othercmd arg1 arg2'

    $ taskqueuectl shell

In order to make use of the cPanel::TaskQueue, you need some way to queue the commands you want to process or schedule commands for later execution. It is also useful to be able to query the queue to see what commands are planned to run.

The taskqueuectl program provides an interface to perform these functions from a command line. It also provides a shell which allows running multiple commands without restarting the program each time. The program does not provide every piece of functionality you will probably need for working with the queue, it is not designed to be the perfect client.

Instead, it provides a starting point that shows you how different operations should be performed and gives a platform for experimenting with a running queue. It can also be used as a minimal command line client for querying a queue that is actually being managed by a more complete system.

DESCRIPTION

The taskqueuectl program provides a simple interface to query and modify a cPanel::TaskQueue. It does not provide any support for running the commands in the queue.

In order to execute the taskqueuectl program, you need to specify some configuration information so that the program can find the queue and plugins needed to function. This configuration is provided either by command line parameters or a configuration file.

CONFIGURATION

The taskqueuectl program is configured through command line options or a configuration file. If the first parameter to the program starts with an @, the rest of the argument is treated as a configuration file name. If no configuration is passed on the command line, the program defaults to reading taskqueue.cfg in the current directory.

The configuration file just contains the command line options, one per line. Blank lines are ignored. Everything after the # character is treated as a comment and discarded.

The command line options that configure the program are

--dir={queuedir}

This required parameter specifies a directory in which we can find the TaskQueue's state files. The files to be accessed should be readable by the current user for the program to work.

--qname={queue name}

This optional parameter specifies the name associated with the TaskQueue object. It is used to create the name of the TaskQueue state file. If not supplied, a default value of main is used.

--sname={scheduler name}

This optional parameter specifies the name associated with the TaskQueue::Scheduler object. It is used to create the name of the TaskQueue::Scheduler state file. If not supplied, the specified queue name is used.

--plugindir={directory}

This required parameter may be specified multiple times to specify one or more directories to search for plugins. This directory name should not contain the namespace.

For example, if we are looking for the plugin TaskProcessor::NewCommands in the namespace TaskProcessor, and the plugin file is located at /usr/local/lib/taskplugins/TaskProcessor/NewCommands.pm. The plugindir would be /usr/local/lib/taskplugins and the namespace would be TaskProcessor.

These directories are also added to the Perl include directory list to allow loading any plugins we find.

--namespace={ns}

This optional parameter may be supplied multiple times to specify namespaces to search for plugins. If none are supplied, the default cPanel::TaskProcessors is used.

--plugin={modulename}

This optional parameter may be specified multiple times to specify the particular plugins to load. If this parameter is supplied, the plugin directories are not searched for plugins. Instead, only the specified plugins are loaded.

--logfile={filename}

This parameter is not actually used. But it is supported so that the configuration of all of the tools is consistent.

COMMANDS

The taskqueuectl program supports a number of commands to query or manipulate the configured TaskQueue. The official list of executable commands is defined by the cPanel::TaskQueue::Ctrl module. You can use perldoc cPanel::TaskQueue::Ctrl to get more information on the commands:

queue 'cmd string' ...

Queue the supplied command string or command strings. If the command string contains spaces, it must be quoted.

unqueue {taskid} ...

Unqueue one or more tasks by id.

schedule [at {time}] 'cmd string' ...

Schedule the specifies command string to be queued at the time specified by {time} where {time} is in epoch seconds. If the at {time} phrase is missing, the commands string is scheduled to be queued now (or the next step in processing).

More than one command string may be specified.

schedule after {seconds} 'cmd string' ...

Schedule the specifies command string to be queued in {seconds} seconds. More than one command string may be specified.

unschedule {taskid} ...

Unschedule one or more tasks by id.

list [verbose] [active|waiting|scheduled]

List the tasks currently in the task queue. If the verbose option is specified, display more information about each task.

The active, waiting, and scheduled options causes the list command to only display tasks in the specified state. If none of these options is supplied the list command defaults to displaying them all.

find task {taskid}

Find a task in the processing or waiting state with the matching task id.

find command {cmdname}

Display all commands that match the specified command name. This is just the name of the command, not the full command string.

plugins [verbose]

Display which plugins were found and loaded. If the verbose option is provided, also display all of the commands.

commands [modulename]

List commands supported by all supported plugins. If a module name is supplied, only display commands for that plugin.

status

Print the status of the Task Queue and Scheduler.

In addition, there are a few commands that don't effect the TaskQueue but just apply to the taskqueuectl program itself.

shell

Using the shell command on the command line opens a command line shell that you can use for entering multiple commands, one per line. The shell does not allow you to execute the shell command again.

help [cmd]

Display a short synopsis of the various commands. If a taskqueuectl command is supplied as an argument, only the synopsis for that command is displayed.

man [cmd]

Display a synopsis and explanatory text on the various commands. If a taskqueuectl command is supplied as an argument, only the synopsis and explanation for that command is displayed.

quit

q

exit

These commands are synonyms that all exit the shell.

DEPENDENCIES

In addition to the normal dependencies of the cPanel::TaskQueue module, this script requires Term::Readline to run.

INCOMPATIBILITIES

None reported.

BUGS AND LIMITATIONS

No outstanding bugs.

LICENCE AND COPYRIGHT

Copyright (c) 2010, cPanel, Inc. All rights reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.

DISCLAIMER OF WARRANTY

BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

cpanm cPanel::TaskQueue

perl -MCPAN -e shell
install cPanel::TaskQueue