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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>BeanstalkD: An Introduction to queuing</title>
<!-- metadata -->
<meta name="generator" content="S5" />
<meta name="version" content="S5 1.1" />
<meta name="presdate" content="20100425" />
<meta name="author" content="Alister Bulman" />
<meta name="company" content="n/a" />
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</head>
<body>
<div class="layout">
<div id="controls"><!-- DO NOT EDIT --></div>
<div id="currentSlide"><!-- DO NOT EDIT --></div>
<div id="header"></div>
<div id="footer">
<h1>Beanstalk job queue</h1>
<h2>PHP London meetup • May 6th, 2010</h2>
</div>
</div>
<div class="presentation">
<div class="slide">
<h1>Beanstalkd:</h1>
<h2>An Introduction</h2>
<p>PHP London, May 6th 2010</p>
<h3>Alister Bulman</h3>
<p><a href="http://abulman.co.uk/">http://abulman.co.uk</a></p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>self::about()</h1>
<h2>self::current()</h2>
<p>Scaling PHP-based systems, with related technologies. PHP Developer at
<a href="http://binweevils.com">Binweevils.com</a>. All the while trying to
avoid getting phone calls on weekends...</p>
<h2>self::prev()</h2>
<p>Programming PHP since 1999, PHP v3, (@11 years ago). Previously in
everything from a ZX81, BBC/Electron, 6502 to 8086 Assembler, Pascal and C/C++
before PHP</p>
<div class="handout">
<p>Programming since 198-cough</p>
</div>
</div>
<!-- ======================= -->
<div class="slide">
<h1>What Is A ?</h1>
<ul>
<li>Job Queue</li>
<li>Work Queue</li>
<li>Task Queue</li>
<li>Message Queue</li>
</ul>
<p>For our purposes, they all describe much the same thing</p>
<div class="handout">
<p>'Message Queue' is usually more 'enterprise-y, and often has
additional'Business Intelligence' within it.</p>
</div>
</div>
<!-- ======================= -->
<div class="slide">
<h1>What Is A Job Queue?</h1>
<p><blockquote>(Beanstalkd) is a simple, fast workqueue service. Its interface is
generic, but was originally designed for reducing the latency of page views in
high-volume web applications by running time-consuming tasks asynchronously.
</blockquote>
<cite><a href="http://kr.github.com/beanstalkd/">http://kr.github.com/beanstalkd/</a></cite>
</p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Huh?</h1>
<ul class="incremental">
<p>It's a big to-do list.</p>
<p>You send it a message, and then can retrieve it later</p>
<div class="handout">
<p>Sometimes, you won't be pulling jobs out in the same order you that
put them in - but we'll come back to that later</p>
</div>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Why are job queues useful?</h1>
<p>Many long running, or intensive tasks could be done in the background</p>
<p> - Background or Parallel Processing</p>
<hr/>
<ul class="incremental">
<li>processing image or videos</li>
<li>Sending out emails</li>
<li>Fetching information in the background - like RSS feeds</li>
<li>Preparing information for later use</li>
</ul>
<div class="handout">
<p>The classic problem is image uploads. Even happy-snap digital cameras
can produce an image that is 3-4+ megabytes. You can't just store that
and end up resizing it in the browser. You have to resize it, but you also
can't do it in the same PHP process that uploaded it - it takes too much
time - and memory.</p>
<p>Don't even try to resize 5+ GB of 1080p quality HD video</p>
<p>Use of queues at Flickr<br />
- the most popular use isn't even about resizing images</p>
</div>
</div>
<!-- ======================= -->
<div class="slide">
<h1>The Advantages</h1>
<ul>
<li>Parallel and/or asyncronous work
<ul>
<li>it's too much to do while we wait</li>
<li>do it in the background, while we are doing other things</li>
</ul>
</li>
<li>Scales easily - run more workers
<ul>
<li>if the work can be done independently of data</li>
<li>workers can be run almost anywhere within your cluster</li>
<li>particular jobs can also be directed to specific machines</li>
</ul>
</li>
<li>Call functionality written in other languages</li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>How It Works</h1>
<img src="Msmq.jpg" width="518" height="210" alt="Msmq" align="right" />
<ul class="incremental">
<li>Queues: Acts as a message buffer between producer and consumer</li>
<li>Daemon: When messages are released to the consumer/worker</li>
<li>Producer: Creates messages that are put into the queue</li>
<li>Consumer/Worker: Pulls messages from the queue, and works on them</li>
</ul>
<div class="handout">
<p>We've talked about what you can do - and why you would, lets see how.
How would a queue be structured</p>
</div>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Queueing via a database</h1>
<ul>
<li>An obvious early step</li>
<li>Not actually so well suited, especially with many transactions <br />
<small>high transaction costs - locking to ensure only one worker can get a message</small>
</li>
<li>PEAR's Mail_Queue <small>can work very well with small number of 'workers'</small></li>
</ul>
<hr/>
<p><strong>Polling</strong><br />
<small>Gizza job! Gizza job! Gizza job! Gizza job! Gizza job! Gizza job! Gizza job!
Gizza job! Gizza job! Gizza job! Gizza job! Gizza job! Gizza job! Gizza job! Gizza
job! Gizza job! Gizza job! Gizza job! Gizza job! </small></small></p>
<p><strong>Blocking</strong><br />
<small>I'll wait here till you have something</small></p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Dedicated queue systems</h1>
<h2>There are a number of jobQueue / message queues</h2>
<ul>
<li>ActiveMQ</li>
<li>RabbitMQ, written in Erlang (recently bought by VMWare)</li>
<li>Amazon SQS</li>
<li>Gearman, like so many other things, originally created by Livejournal</li>
<li>Zero MQ</li>
<li>Sparrow, Starling, and now Kestrel by Twitter</li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Beanstalkd</h1>
<p>Many language bindings are available</p>
<p>Quite easy to write, as it's a simple text-based format, ala Memcached</p>
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<p>The daemon is equally dumb as a classic MemcacheD. Talking to multiple
servers is done from the client-side.</p>
<div class="handout">
<p>BeanstalkD was written in C for a Facebook app called 'Causes' -
which was written in RubyOnRails</p>
<p>Not to be confused with the 'Beanstalkapp.com', which is remote
SVN & GIT version control</p>
</div>
</div>
<!-- ======================= -->
<div class="slide">
<h4>History</h4>
<p><small>Philotic, Inc. developed beanstalk to improve the response time for the
Causes on Facebook application (with over 9.5 million users). Beanstalk
decreased the average response time for the most common pages to a tiny
fraction of the original, significantly improving the user experience.</small></p>
<ul>
<li><a href="http://kr.github.com/beanstalkd/">http://kr.github.com/beanstalkd/</a></li>
<li><a href="http://github.com/kr/beanstalkd">http://github.com/kr/beanstalkd</a></li>
<li><a href="http://wiki.github.com/kr/beanstalkd/faq">http://wiki.github.com/kr/beanstalkd/faq</a></li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Beanstalkd is a series of TUBES</h1>
<img src="the-internet-a-series-of-tubes-300x262.jpg" alt="Beanstalkd is a series of TUBES"
align="left" style="padding-right: 1em; padding-bottom: 1em;" />
<p style="margin-left: 50%;display:block;"><blockquote>
... The Internet is not something that you just dump something on. It's not a
big truck. It's a series of tubes. And if you don't understand, those tubes
can be filled and if they are filled, when you put your message in, it gets
in line and it's going to be delayed by anyone that puts into that tube
enormous amounts of material. - former United States Senator Ted Stevens (R-Alaska)</blockquote></p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Killer features</h1>
<ul>
<li>Tube names</li>
<li>Priorities</li>
<li>Delays</li>
<li>TTR - time to run</li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Tubes</h1>
<p>Named tubes/queues can be created at will and have messages sent to them</p>
<p>'default' queue is always created and read from, unless overridden</p>
<p>Now _ with _ added _ underlines!</p>
<div class="handout">
<p>Pick a given set, and stick to them. Make sure you have at least a running worker reading from every tube</p>
<p>watch a tube-name based on the machine's hostname - file uploads onto a specific machine</p>
</div>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Priorities</h1>
<p>0 to 4,294,967,295 (2^<sup>32</sup>)</p>
<p>Most urgent: 0</p>
<p>I'd suggest a range from 100 to 1000 - just be consistant</p>
<pre>
class YourApp_Task {
const PRI_CHECK_EMAIL = 500;
const PRI_PROCESS_IMAGE = 800;
const PRI_LOGIN_ACTION = 100;
}
$priority = YourApp_Task::PRI_LOGIN_ACTION;
</pre>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Delay</h1>
<h2>Do this after <em>x</em> seconds</h2>
<p>Hold a message within the queue before allowing it to be reserved, and acted upon</p>
<p><em>I want you to do this job - but in at least x seconds time</em></p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>TTR</h1>
<p>How long can a job be reserved (being worked on) before it's retried?</p>
<p>When a job has been reserved. a timer starts counting down from the job's TTR.</p>
<ul class="incremental">
<li>If the timer reaches zero, the job gets put back in the ready queue for another task to run it.</li>
<li>If the job is buried, deleted, or released before the timer runs out, the timer ceases to exist.</li>
<li>If the job is 'touch'ed before the timer reaches zero, the timer starts over counting down from TTR.</li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>lifecycle of a job</h1>
<small><pre>
put reserve delete
-----> [READY] ---------> [RESERVED] --------> *poof*
Here is a picture with more possibilities:
put with delay release with delay
----------------> [DELAYED] <------------.
| |
| (time passes) |
| |
put v reserve | delete
-----------------> [READY] ---------> [RESERVED] --------> *poof*
^ ^ | |
| \ release | |
| `-------------' |
| |
| |
| kick |
| bury |
[BURIED] <---------------'
|
| delete
`--------> *poof*</pre></small>
</div>
<!-- ======================= -->
<div class="slide">
<h1>What to send through the queue?</h1>
<ul>
<li>'Clean URLs':
<ul><li>/tasks/image/resize/filename/example.jpg/sizeX/640/sizeY/480</li>
<li>/tasks/member/logintasks/id/12345</li>
<li>/tasks/mail/fetchcounts/id/12345</li>
</ul>
<li>PHP's serialize/deserialize</li>
<li>JSON
<ul><li>{"module":"task","controller":"image","action":"resize",
"params":{"filename":"example1.jpg"}}</li>
</ul>
</li>
<li>plain text: RESTART, STOP, UPDATE-COUNTS</li>
</ul>
<p>64KB default limit.</p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Queuing / Running</h1>
<h2>Producer (queues jobs)</h2>
<small><pre style="background-color: silver"><?php
require_once 'pheanstalk_init.php';
$pheanstalk = new Pheanstalk('127.0.0.1');
$pheanstalk->useTube('testtube')
->put("job payload goes here\n");
</pre></small>
<h2>worker (performs jobs)</h2>
<small><pre style="background-color: silver"><?php
require_once 'pheanstalk_init.php';
$pheanstalk = new Pheanstalk('127.0.0.1');
$job = $pheanstalk->watch('testtube')
->ignore('default')
->reserve();
// <em>handwave</em> to run the job
echo $job->getData();
$pheanstalk->delete($job);
</pre></small>
</div>
<!-- ======================= -->
<!--
<div class="slide">
<h1>Running workers</h1>
<small><small><pre><code>
#!/bin/bash
# a shell script that keeps looping until an exit code is given
nice php -q -f ./cli-beanstalk-worker.php -- $@
ERR=$?
if [ $ERR -eq 97 ] # a planned pause, then restart
then
sleep 1;
exec $0 $@;
fi
if [ $ERR -eq 98 ] # a planned restart - instantly
then
exec $0 $@;
fi
if [ $ERR -eq 99 ] # planned complete exit
then
exit 0;
fi
# unplanned exit, pause, and restart
echo "unplanned restart: err:" $ERR;
echo "sleeping for 1 sec"
sleep 1
exec $0 $@
</code></pre></small></small>
</div>
-->
<!-- ======================= -->
<!--
<div class="slide">
<h1>Running workers - the PHP script</h1>
<small><small><pre><code>
#!/usr/bin/php
<?php
// cli-beanstalk-worker.php
// for testing of the BASH script
exit (rand(95, 100));
/* normally we would return one of
# 97 - planned pause/restart
# 98 - planned restart
# 99 - planned stop, exit.
# anything else is an unplanned restart
*/
</code></pre></small></small>
</div>
-->
<!-- ======================= -->
<div class="slide">
<h1>Behind the curtains</h1>
<h2>telnet localhost 11300</h2>
<ul>
<li><pre><code>use <tube>\r\n</pre></code></li>
<li><pre><code>put <pri> <delay> <ttr> <bytes>\r\n<br /><data>\r\n</pre></code></li>
<li><pre><code>watch <tube>\r\n</pre></code></li>
<li><pre><code>reserve\r\n</pre></code>
<p>Alternatively, if you don't want to have to poll for a new job, you can specify a timeout:</p></li>
<li><pre><code>reserve-with-timeout <seconds>\r\n</pre></code></li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>It's pretty quick</h1>
<small><pre><code>
<?php
require 'pheanstalk_init.php';
$pheanstalk = new Pheanstalk('127.0.0.1');
for ($i = 10000; $i > 0; $i --) {
$pheanstalk->put("job payload goes here\n");
}
</code></pre></small>
<p>10,000 simple jobs queued:
<pre>$ time php -f fillQueue.php
real 0m3.272s
user 0m1.764s
sys 0m0.768s</pre></p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>And to fetch them</h1>
<small><pre><code>
<?php
require 'pheanstalk_init.php';
$pheanstalk = new Pheanstalk('127.0.0.1');
for ($i = 10000; $i > 0; $i --)
{
$job = $pheanstalk->reserve(2); // reserve - with timeout
if (! $job) {
continue;
}
$job->getData();
$pheanstalk->delete($job);
}
</code></pre></small>
<p>10,000 simple jobs de-queued:
<pre>$ time php -f getQueue.php
real 0m4.973s
user 0m2.584s
sys 0m1.304s</pre></p>
</div>
<!-- ======================= -->
<div class="slide">
<h1>stats</h1>
<small><pre># <strong>telnet localhost 11300</strong>
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
<strong>stats</strong>
OK 814
---
current-jobs-urgent: 7145
current-jobs-ready: 7145
current-jobs-reserved: 0
.....
current-tubes: 1
current-connections: 1
current-producers: 0
current-workers: 0
current-waiting: 0
total-connections: 5
pid: 5756
....
</pre></small>
</div>
<!-- ======================= -->
<div class="slide">
<h1>In Summary</h1>
<ul>
<li>Job queuing systems can give a lot of flexability to pass messages into background processing</li>
<li>Background tasks are not subject to the same limits as a webpage would be - time or memory</li>
<li>Work can be distributed across a number of machines</li>
<li>Data can be generated and stored by the worker for later use</li>
<li>Limited by your imagination on how to use it</li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Thanks</h1>
<ul>
<li>PHP London and the PHP Conference</li>
<li>Remo Biagioni of Stickyeyes.com (presented at PHP conference) and mentioned his work with Beanstalkd to scale</li>
<li><img src="Msmq.jpg" width="200" alt="Msmq" align="left" />
<a href="http://en.wikipedia.org/wiki/File:Msmq.jpg">http://en.wikipedia.org/wiki/File:Msmq.jpg</a>
USGOV, public domain </li>
<li style="clear:left">Beanstalkd FAQ and github pages at <a href="http://kr.github.com/beanstalkd/">http://kr.github.com/beanstalkd/</a></li>
</ul>
</div>
<!-- ======================= -->
<div class="slide">
<h1>Questions ?</h1>
<ul>
<li>Alister Bulman</li>
<li><a href="http://abulman.co.uk">http://abulman.co.uk</a></li>
<li><a href="http://www.google.com/profiles/abulman">http://www.google.com/profiles/abulman</a></li>
<li>and elsewhere</li>
</ul>
<p>Beanstalkd on Github: <a href="http://kr.github.com/beanstalkd/">http://kr.github.com/beanstalkd/</a></p>
</div>
</div><!-- /div class="presentation" -->
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