Creating a Job

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Working with The Job Queue API

Queued Jobs

Recurring Jobs

One-Time Deferred Tasks (jobs)

Using the Job Queue from the Zend Server for IBM i Administration Interface

 

The Zend Server for IBM i Job Queue component provides the ability to off-load script execution using Jobs . A Job is in essence a command to execute a PHP script according to the specific parameters you give it. The Job Queue component manages the timing and execution of jobs in the system.

 

Jobs can be created to facilitate a wide range of situations that require you to asynchronously run PHP code. Here are a few examples:

Working with The Job Queue API

The Job Queue API is a set of functions that allow you to create, define and manage the execution of PHP code using a job.

There are three types of Jobs you can create with the Job Queue API

Queued Jobs

This procedure describes how to create a Job that will be triggered as a result of end-user activity using the Job Queue API.

 

 

Instructions on how to complete a procedure

To create a Job that will be triggered as a result of end-user activity:

  1. Open your existing code.

  2. Isolate the part of the code that should be executed as a job.
    This code should be a viable script that performs some sort of action that can be run at a later time without disturbing the general functionality (such as sending an e-mail, confirming a credit card etc.).

  3. Put the code into a file and name the file. The location and the name of the file will become the value of the URL parameter therefore always provide descriptive names and place job files in the same location.

  4. In the original code, replace the code you removed with a call to the Job Queue function createHttpJob.

  5. In the function, pass additional GET parameters in the job's URL query string, to handle different data.

  6. Publish the fixed code to your webserver.

The next time the code is used the job will be triggered inside the code. To find out how the job ran go to Monitor | Jobs.

To see what jobs are currently running go to Monitor | Queue Statistics.

For additional information on handling jobs see Managing Jobs.

 

Usage Example

Example:

The following example shows what the original code looks like. How it will look like using the Job Queue API, and what the new Job file looks like.

Before converting to a job:

<?php
function validate_credit_card_number($string)
{
    if(
preg_match('/^([0-9]{4})[\-|\s]*([0-9]{4})[\-|\s]*([0-9]{4})[\-|\s]*([0-9]{2,4})$/'$string))
    {
        return 
TRUE;
    }
    else
    {
        return 
FALSE;
    }
}
// here we call the function to validate the credit card validate_credit_card_number($_POST['credit_code']);

Instead of calling the function from inside the script we will create a job that will be executed when we specify it to run. The script will be replaced with a call to the Job Queue API as follows:

The application script after modification:

<?php


$cc 
$_POST['credit_card'];


$q = new ZendJobQueue();


$ts date('Y-m-d H:i:s'time()+10);


$id=$q->createHttpJob('/jobs/validate_credit_card.php',array('credit_card'=>$cc),array('name'=>'Credit


card validation using a single job execution scheduled to run after 10 seconds'
,'schedule_time'=>$ts));


if(!
$id){


exit(
1);

The new job script:

The job script:
<?php
function validate_credit_card_number($string)
{
    if(
preg_match('/^([0-9]{4})[\-|\s]*([0-9]{4})[\-|\s]*([0-9]{4})[\-|\s]*([0-9]{2,4})$/'$string))
    {
        return 
ZendJobQueue::setCurrentJobStatus(ZendJobQueue::OK);
    }
    else
    {
        return 
ZendJobQueue::setCurrentJobStatus(ZendJobQueue::FAILED);
    }
}

$params ZendJobQueue::getCurrentJobParams();

validate_credit_card_number($params['credit_card']);
?>

 

Recurring Jobs

This procedure describes how to create a recurring Job. A recurring job will be executed periodically based on a defined schedule.

Creating recurring jobs from API is usually useful when the application’s workflow requires the creation (and usually subsequent deletion) of recurring tasks following some user interaction. For example, in a feed aggregator, it might make sense to create a recurring job that hourly pulls updates for each new feed added by the user. Another example might be a reporting system in which users can create and delete daily, weekly or monthly reports.

 

 

Instructions on how to complete a procedure

To create a recurring job:

  1. Follow the instructions in Queued Jobs to create an createHttpJob job using the API.

  2. Pass the schedule option as part of the options parameter to describe the recurrance schedule.

The schedule option is a CRON-like expression that consists of string with 5 fields separated by spaces. The fields define the minute, hour, day of month, month and day of week (in this order) in which the job will run.

In each field, you can use one of the following notations:

Usage Example

Example:

The following example represents a job that will run every day at 3:15am:

$job = $jq->createHttpJob('http://localhost/jobs/feed/405', null, array(

'schedule' => '15 3 * * *'

 

Ranges for each field:

Field

Range

Comments

Minute

0 - 59

 

Hour

0 - 23

In 24 hour format, where 0 is midnight

Day of Month

1 - 31

29,30 and 31 will only work for months of that length

Month

1 - 12

 

Day of Week

0 - 7

Sunday is either 0 or 7

One-Time Deferred Tasks (jobs)

This procedure describes how to create a one-time deferred task. In some use cases, it makes sense to defer a certain task to a later time. For example, many applications have clear peak hours (e.g. between 8am and 11pm, or like in many Intranet applications, during office work hours).

If these applications need to perform some off-line processing, it might make sense to defer some of the heavy processing tasks to off hours (in our examples to late night or early morning hours), in order to maximize the efficiency of hardware utilization.

 

 

Instructions on how to complete a procedure

To create a time deferred task:

  1. Follow the instructions in Queued Jobs to create an createHttpJob job using the API.

  2. Pass a date/time string as the schedule_time option, as part of the options array passed as the 3rd parameter to createHttpJob().

Note

The format used in date() to pass the execution time – this is an SQL-like ‘YYYY-MM-DD hh:mm:ss’format (e.g. “2009-06-25 23:45:00” for June 25th 2009 at 45 minutes past 11pm).

Zend Job Queue is not designed to execute jobs exactly on the specified time. For example, if the queue is limited to execute 10 jobs concurrently (more on that later on), and 1,000 jobs are scheduled for the exact same time – jobs will have to wait until other jobs finish. You should consider the schedule_time option as a request not to run a job before this time.

 

Usage Example

Example:

The following example shows a time-deferred task that has been scheduled to run a process at 2:00am.

$options = array(

'schedule_time' => date('Y-m-d h:i:s', strtotime('tomorrow 2am'))

);

$jq->createHttpJob('http://localhost/jobs/formproc.php', $_POST, $options);

Note:

the format used in date() to pass the execution time – this is an SQL-like ‘YYYY-MM-DD hh:mm:ss’ format (e.g. "2009-.6-25 23:45:00" for June 25th 2009 at 45 minutes past 11pm).

Using the Job Queue from the Zend Server for IBM i Administration Interface

The Zend Server for IBM i administration interface provides tools for creating recurring jobs. These jobs have a set schedule and will be run at specific times.

This procedure describes how to create a recurring job.

 

 

Instructions on how to complete a procedure

To create a recurring job:

  1. In the administration Interface go to Rule Management | Recurring Jobs

  2. Click new_recurring_job.png to open the New Scheduling Rule page.

  3. Enter the following rule related information:

    1. URL - the path indicating to where the code is for the job to execute and the server on which to run it.

    2. Name - Optional, a name describing the job

    3. Application - Optional, the name of the application the job is related to. This information can be used for grouping jobs.

  4. Define when the job should run by using the time options (Hourly, Daily, Weekly or Monthly). Selecting an option will change the parameters displayed. For example selecting daily will display hour and minute options whereas, weekly will display the days of the week.
    When all the settings are properly defined, the "Create Rule" button will change from Grey to Blue.

  5. Click jobs_create_rule.png to save the changes.

As soon as the new Recurring Job is saved, it will be put in the Job Queue at the time specified in the Rule.

To find out how the job ran go to Monitor | Jobs.

To see what jobs are currently running go to Monitor | Queue Statistics.

For additional information on handling jobs see Managing Jobs.

Note:

The Jobs and Queues Statistics pages display information about all the Jobs in your system, including Jobs triggered by the Job Queue API.

 

 

Related Links

Related Links:

Jobs

Job Details
Managing Jobs
Filtering Jobs  
Job Queue Component