Task Scheduling and Asynchronous Processing Evolved. Zend Server Job Queue

Task Scheduling and Asynchronous Processing Evolved. Zend Server Job Queue By Sam Hennessy – Zend Professional Services Consultant

Offline Processing
Why?
Perceived performance
Managing load
Any work that isn’t needed for giving feedback to the user should be done offline.

Offline Processing Examples
Sending e-mails
Processing orders
Indexing new content
Cleaning the database or file system
Either periodically or after some user action
Pulling an RSS feed every hour
Checking exchange rates every day
Generating periodical reports

Blog Example Post comment Save in the DB Rebuild RSS feeds Send email notifications Display “Thank You” message

Blog Example Post comment Save in the DB Rebuild RSS feeds Send email notifications Display thank you message Queue Tasks Job Queue

Architectural Overview PHP + Job Queue Extension TCP or Unix Socket Job Queue Damon Persistent Storage (SQLite) HTTP Request Executing Server

Goals Of Zend Job Queues
Ability to off-load PHP code execution
Jobs should never be “lost”
Ability to queue jobs from PHP API
Ability to create recurring & deferred jobs
Management GUI

The ZendJobQueue class
The ZendJobQueue class contains almost all the PHP API for Job Queue
To perform most tasks, you will need to connect to a Job Queue server by instantiating a ZendJobQueue object:
// Connect to the default JQ server $queue = new ZendJobQueue (); // Connect to any other JQ server $queue = new ZendJobQueue ( "tcp://1.2.3.4:5678" );

Creating Jobs
All jobs are created using the ZendJobQueue::createHttpJob() method
Passing a partial URL will create the job with $_SERVER['HTTP_HOST'] in the host nam e
$queue = new ZendJobQueue (); $queue -> createHttpJob ( 'http://backend.local/jobs/somejob.php' ); $queue -> createHttpJob ( '/jobs/otherjob.php' );

Passing Parameters
Simple parameters can be passed as part of the query string
Complex parameters can also be passed
Pass any serializable data as the 2 nd parameter of createHttpJob()
Data will be JSON-encoded – so anything which can be represented as JSON can be used
$queue -> createHttpJob ( '/jobs/otherjob.php?foo=bar&uid=1792' );

Passing Parameters (example) $params = array( 'cart' => array( 'items' => array( array( 'id' => 324 , 'qty' => 1 , 'price' => 19.95 ), array( 'id' => 75 , 'qty' => 2 , 'price' => 14.95 , 'size' => 'XL' ) ), 'total' => 49.85 , 'coupon' => null , 'giftwrap' => true ), 'user' => $user ); $queue -> createHttpJob ( 'http://backend/jobs/checkout.php' , $params );

Accessing Parameters
Inside the Job code, use the ZendJobQueue::getCurrentJobParams() static method to get the job's parameters:
You can also json_decode() the raw POST data
$params = ZendJobQueue :: getCurrentJobParams (); $params = json_decode ( file_get_contents ( 'php://input' ));

Additional Job Options
The 3 rd parameter of createHttpJob is an associative array of parameters:
name
priority
persistent
predecessor
http_headers
schedule
schedule_time

Creating Deferred Jobs
You can set a job's (estimated) execution time by passing the schedule_time option:
The job will not run before the specified time
// Process the form at 3:00 am $runAt = date ( 'Y-m-d h:i:s' , strtotime ( '+1 day 3:00am' )); $options = array( 'schedule_time' => $runAt ); $queue -> createHttpJob ( 'http://backend/jobs/process.php' , $_POST , $options );

Creating Recurring Jobs
You can create a recurring job from API using the schedule option
This option takes a cron-like expression that specifies scheduling
// Run on Sunday, Monday, and Tuesday at midnight $jq -> createHttpJob ( 'http://localhost/jobs/feed/405' , null , array( 'schedule' => '0 0 * * 0,1,2' )); // Run every other day of the month at 2:30pm $jq -> createHttpJob ( 'http://localhost/jobs/feed/405' , null , array( 'schedule' => '30 14 */2 * *' ));

Reporting Logical Failures
A logical failure happens when something has programatically failed
e.g. you were unable to send an e-mail or connect to a SOAP web service
Unlike an execution failure which is a technical failure (e.g. 500 error from server)
Logical failures need to be reported by the programmer:
ZendJobQueue :: setCurrentJobStatus ( ZendJobQueue :: OK ); if (! doTheImportantStuff ()) { ZendJobQueue :: setCurrentJobStatus ( ZendJobQueue :: ERROR ); }

Job HTTP Request POST /job.php HTTP/1.0 Host: localhost Content-Type: text/json Content-Length: 34 Connection: close Accept: */* USER_AGENT: Zend Server Job Queue/4.1 Cookie: SESS273df6b85bb9a37ced781f806219fc6a=7k6atppt8akccooobs26htsim7; ZDEDebuggerPresent=php,phtml,php3 {"var1":15,"nested":["a","b","c"]}

Job HTTP Response HTTP/1.1 200 OK Date: Thu, 10 Sep 2009 17:29:20 GMT Server: Apache/2.2.9 (Debian) PHP/5.2.10 X-Powered-By: PHP/5.2.10 ZendServer/4.0 Set-Cookie: ZDEDebuggerPresent=php,phtml,php3; path=/ X-Job-Queue-Status: 1 Something is wrong! Vary: Accept-Encoding Content-Length: 152 Connection: close Content-Type: text/html array(2) { ["var1"]=> int(15) ["nested"]=> array(3) { [0]=> string(1) "a" [1]=> string(1) "b" [2]=> string(1) "c" } }

Live Demo

Questions?

Thank You!
Please come find me if you have any more questions

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Task Scheduling and Asynchronous Processing Evolved. Zend Server Job Queue

by Sam Hennessy on Oct 28, 2009

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Task Scheduling and Asynchronous Processing Evolved. Zend Server Job Queue — Presentation Transcript