Gearman Getting Started Notes

1. Introduction

Gearman is a tool that can delegate work to other machines or processes.
Official website address: http://gearman.org/

Gearman usually consists of three parts, client+worker+task server. The worker executes the job sent by the client, and then returns it to the client through the job server. Gearman provides Client and Worker APIs and uses these APIs to communicate with the job server.
This is the working principle diagram:

2. Installation

The official installation guide is at: http://gearman.org/getting-started/
The following introduces the specific installation process in ubuntu:

1. In ubuntu14.04, Python-Software-Properties is replaced by Software-Properties-Common.

<code>sudo apt-get install software-properties-common
sudo add-apt-repository ppa:gearman-developers/ppa
sudo apt-get update
</code>

2. Install GearmanJobServer, Dev Tools, Perform Upgrade

<code>sudo apt-get install gearman-job-server libgearman-dev
sudo apt-get install gearman-tools
sudo apt-get upgrade
</code>

3 .If there is no PECL, install PECL and use PECL to install Gearman (CLI, Client, Worker)

<code>sudo apt-get install php-pear
sudo apt-get install php5-dev
sudo pecl install gearman
</code>

4. Modify php.ini (CLI and Server) to Use Gearman

<code>sudo vi /etc/php5/cli/php.ini
</code>

Add in Dynamic Extensions:
extension=gearman.so

3. Use gearman in php

1. How to call gearman in php

php view version

<code><?php print gearman_version() . "\n"; ?>
运行方式：php test.php
</code>

Build a worker

<code><?php $worker= new GearmanWorker();
    $worker->addServer();
    $worker->addFunction("reverse", "my_reverse_function");
    while ($worker->work());

    function my_reverse_function($job){
      return strrev($job->workload());
    }
?>
</code>

After running this, you need ctrl+c to terminate the program . This code creates a worker object, adds the default server, and registers the reverse callback function. The program will enter an infinite loop. Whenever a job enters, the callback function will be executed. Here, the string is simply reversed and then returned.

Build a Client

client is similar to a worker, create the following server.php

<code><?php $client=new GearmanClient();
$client->addServer();
print $client->do("reverse","Hello World!");
?>
</code>

Look at the execution results:

Build an image resize worker

<code><?php $worker= new GearmanWorker();
$worker->addServer();
$worker->addFunction("resize", "my_resize_function");
while ($worker->work());

function my_resize_function($job)
{
  $thumb = new Imagick();
  $thumb->readImageBlob($job->workload());

  if ($thumb->getImageHeight() > 600)
    $thumb->scaleImage(0, 600);
  else if ($thumb->getImageWidth() > 800)
    $thumb->scaleImage(800, 0);

  return $thumb->getImageBlob();
}
?>
</code>

php requires ImageMagick support, installation method:

<code>sudo wget http://www.imagemagick.org/download/ImageMagick.tar.gz
tar -xzvf ImageMagick.tar.gz
cd ImageMagick
sudo ./configure -prefix=/usr/local/imagemagick -enable-lzw -with-modules && make && make install
</code>

Resize Client

Here we use the command to call the client

<code>gearman -f resize  thumb.jpg
</code>

2. Do not use php, directly use the command line to use gearman Example

Start a terminal to run the daemon process

<code>sudo gearmand --daemon
</code>

Start a worker, here call the ls command

<code>gearman -w -f ls -- ls -lh
</code>

to start A client

<code>gearman -f ls </code>

can see the output results.

Reference URL: http://gearman.org/getting-started/#client

The above introduces the gearman entry usage notes, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.