GearmanClient::doBackground

(PECL gearman >= 0.5.0)

GearmanClient::doBackground — Run a task in the background

Description

public GearmanClient::doBackground(string $function, string $workload, ?string $unique = null): string

Runs a task in the background, returning a job handle which can be used to get the status of the running task.

Parameters

function: A registered function the worker is to execute
workload: Serialized data to be processed
unique: A unique ID used to identify a particular task

Return Values

The job handle for the submitted task.

Examples

Example #1 Submit and monitor a background job

The worker in this example has an artificial delay introduced to mimic a long running job. The client script periodically checks the status of the running job.

<?php

/* create our object */
$gmclient= new GearmanClient();

/* add the default server */
$gmclient->addServer();

/* run reverse client */
$job_handle = $gmclient->doBackground("reverse", "this is a test");

if ($gmclient->returnCode() != GEARMAN_SUCCESS)
{
  echo "bad return code\n";
  exit;
}

$done = false;
do
{
   sleep(3);
   $stat = $gmclient->jobStatus($job_handle);
   if (!$stat[0]) // the job is known so it is not done
      $done = true;
   echo "Running: " . ($stat[1] ? "true" : "false") . ", numerator: " . $stat[2] . ", denominator: " . $stat[3] . "\n";
}
while(!$done);

echo "done!\n";

?>

The above example will output something similar to:

Running: true, numerator: 3, denominator: 14
Running: true, numerator: 6, denominator: 14
Running: true, numerator: 9, denominator: 14
Running: true, numerator: 12, denominator: 14
Running: false, numerator: 0, denominator: 0
done!

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User Contributed Notes 1 note

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felix at passcod dot name ¶

7 years ago

Behaviour of the unique ID argument:

If it's not provided, it defaults to a UUIDv1 (timestamp + mac address).

Otherwise, if a job with the same unique ID exists (i.e. is either queued or currently executing), then that job is used, not the one you're submitting. This does not apply to past (completed) jobs, and works across the entire job server pool, assuming no partitioning.

Or with code (the values in [brackets] are the server-assigned job identifiers):

<?php

$gearman->doBackground('sleep', '3', '123'); // [H:host:1] Starts sleep(3)
$gearman->doBackground('sleep', '5', '456'); // [H:host:2] Queues sleep(5)
$gearman->doBackground('sleep', '3', '123'); // [H:host:1] Does nothing
$gearman->doBackground('sleep', '1', '123'); // [H:host:1] Also does nothing (diff args don't trigger new jobs)

sleep (3);
// Job 123 [sleep(3)] has finished by now

$gearman->doBackground('sleep', '3', '123'); // [H:host:3] Starts a new job

?>