/**
* Find the next available job from the specified queue and return an
* instance of Job for it.
*
* @param string $queue The name of the queue to check for a job in.
* @return null|object Null when there aren't any waiting jobs, instance of Job when a job was found.
*/
public static function reserve($queue)
{
$payload = Resque::pop($queue);
if (!is_array($payload)) {
return false;
}
return new Job($queue, $payload);
}
/**
* The primary loop for a worker which when called on an instance starts
* the worker's life cycle.
*
* Queues are checked every $interval (seconds) for new jobs.
*/
public function work()
{
$this->log('Starting worker <pop>' . $this . '</pop>', Logger::INFO);
$this->updateProcLine('Worker: starting...');
$this->startup();
$this->log('Listening to queues: <pop>' . implode(', ', $this->queues) . '</pop>, with ' . ($this->blocking ? 'timeout blocking' : 'time interval') . ' <pop>' . $this->interval_string() . '</pop>', Logger::INFO);
while (true) {
if ($this->memoryExceeded()) {
$this->log('Worker memory has been exceeded, aborting', Logger::CRITICAL);
$this->shutdown();
Event::fire(Event::WORKER_LOW_MEMORY, $this);
}
if (!$this->redis->sismember(self::redisKey(), $this->id) or $this->redis->hlen(self::redisKey($this)) == 0) {
$this->log('Worker is not in list of workers or packet is corrupt, aborting', Logger::CRITICAL);
$this->shutdown();
Event::fire(Event::WORKER_CORRUPT, $this);
}
if ($this->shutdown) {
$this->log('Shutting down worker <pop>' . $this . '</pop>', Logger::INFO);
$this->updateProcLine('Worker: shutting down...');
break;
}
if ($this->status == self::STATUS_PAUSED) {
$this->log('Worker paused, trying again in ' . $this->interval_string(), Logger::INFO);
$this->updateProcLine('Worker: paused');
sleep($this->interval);
continue;
}
$this->host->working($this);
$this->redis->hmset(self::redisKey($this), 'memory', memory_get_usage());
Event::fire(Event::WORKER_WORK, $this);
if (!count($this->resolveQueues())) {
$this->log('No queues found, waiting for ' . $this->interval_string(), Logger::INFO);
sleep($this->interval);
continue;
}
$this->queueDelayed();
if ($this->blocking) {
$this->log('Pop blocking with timeout of ' . $this->interval_string(), Logger::INFO);
$this->updateProcLine('Worker: waiting for job on ' . implode(',', $this->queues) . ' with blocking timeout ' . $this->interval_string());
} else {
$this->updateProcLine('Worker: waiting for job on ' . implode(',', $this->queues) . ' with interval ' . $this->interval_string());
}
$job = \Resque::pop($this->resolveQueues(), $this->interval, $this->blocking);
if (!$job instanceof Job) {
if (!$this->blocking) {
$this->log('Sleeping for ' . $this->interval_string(), Logger::INFO);
sleep($this->interval);
}
continue;
}
$this->log('Found a job <pop>' . $job . '</pop>', Logger::NOTICE);
$this->workingOn($job);
Event::fire(Event::WORKER_FORK, array($this, $job));
// Fork into another process
$this->child = pcntl_fork();
// Returning -1 means error in forking
if ($this->child == -1) {
Event::fire(Event::WORKER_FORK_ERROR, array($this, $job));
$this->log('Unable to fork process, this is a fatal error, aborting worker', Logger::ALERT);
$this->log('Re-queuing job <pop>' . $job . '</pop>', Logger::INFO);
// Because it wasn't the job that failed the job is readded to the queue
// so that in can be tried again at a later time
$job->queue();
$this->shutdown();
// In parent if $pid > 0 since pcntl_fork returns process id of child
} elseif ($this->child > 0) {
Event::fire(Event::WORKER_FORK_PARENT, array($this, $job, $this->child));
$this->log('Forked process to run job on pid:' . $this->child, Logger::DEBUG);
$this->updateProcLine('Worker: forked ' . $this->child . ' at ' . strftime('%F %T'));
// Set the PID in redis
$this->redis->hset(self::redisKey($this), 'job_pid', $this->child);
// Wait until the child process finishes before continuing
pcntl_wait($status);
if (!pcntl_wifexited($status) or ($exitStatus = pcntl_wexitstatus($status)) !== 0) {
if ($this->job->getStatus() == Job::STATUS_FAILED) {
$this->log('Job ' . $job . ' failed: "' . $job->failError() . '" in ' . $this->job->execTimeStr(), Logger::ERROR);
} else {
$this->log('Job ' . $job . ' exited with code ' . $exitStatus, Logger::ERROR);
$this->job->fail(new Exception\Dirty($exitStatus));
}
}
} else {
Event::fire(Event::WORKER_FORK_CHILD, array($this, $job, getmypid()));
$this->log('Running job <pop>' . $job . '</pop>', Logger::INFO);
$this->updateProcLine('Job: processing ' . $job->getQueue() . '#' . $job->getId() . ' since ' . strftime('%F %T'));
$this->perform($job);
exit(0);
}
$this->child = null;
$this->doneWorking();
}
}
