NAME
MangoX::Queue - A MongoDB queue implementation using Mango
DESCRIPTION
MangoX::Queue is a MongoDB backed queue implementation using Mango to support blocking and non-blocking queues.
MangoX::Queue makes no attempt to handle the Mango connection, database or collection - pass in a collection to the constructor and MangoX::Queue will use it. The collection can be plain, capped or sharded.
For an introduction to MangoX::Queue, see MangoX::Queue::Tutorial.
SYNOPSIS
Non-blocking
Non-blocking mode requires a running Mojo::IOLoop.
my $queue = MangoX::Queue->new(collection => $mango_collection);
# To add a job
enqueue $queue 'test' => sub { my $id = shift; };
# To set options
enqueue $queue priority => 1, created => bson_time, 'test' => sub { my $id = shift; };
# To watch for a specific job status
watch $queue $id, 'Complete' => sub {
# Job status is 'Complete'
};
# To fetch a job
fetch $queue sub {
my ($job) = @_;
# ...
};
# To get a job by id
get $queue $id => sub { my $job = shift; };
# To requeue a job
requeue $queue $job => sub { my $id = shift; };
# To dequeue a job
dequeue $queue $id => sub { };
# To consume a queue
my $consumer = consume $queue sub {
my ($job) = @_;
# ...
};
# To stop consuming a queue
release $queue $consumer;
# To listen for errors
on $queue error => sub { my ($queue, $error) = @_; };Blocking
my $queue = MangoX::Queue->new(collection => $mango_collection);
# To add a job
my $id = enqueue $queue 'test';
# To set options
my $id = enqueue $queue priority => 1, created => bson_time, 'test';
# To watch for a specific job status
watch $queue $id;
# To fetch a job
my $job = fetch $queue;
# To get a job by id
my $job = get $queue $id;
# To requeue a job
my $id = requeue $queue $job;
# To dequeue a job
dequeue $queue $id;
# To consume a queue
while(my $job = consume $queue) {
# ...
}Other
my $queue = MangoX::Queue->new(collection => $mango_collection);
# To listen for events
on $queue enqueued => sub ( my ($queue, $job) = @_; };
on $queue dequeued => sub ( my ($queue, $job) = @_; };
on $queue consumed => sub { my ($queue, $job) = @_; };
# To register a plugin
plugin $queue 'MangoX::Queue::Plugin::Statsd';ATTRIBUTES
MangoX::Queue implements the following attributes.
collection
my $collection = $queue->collection;
$queue->collection($mango->db('foo')->collection('bar'));
my $queue = MangoX::Queue->new(collection => $collection);The Mango::Collection representing the MongoDB queue collection.
delay
my $delay = $queue->delay;
$queue->delay(MangoX::Queue::Delay->new);The MangoX::Queue::Delay responsible for dynamically controlling the delay between queue queries.
concurrent_job_limit
my $concurrent_job_limit = $queue->concurrent_job_limit;
$queue->concurrent_job_limit(20);The maximum number of concurrent jobs (jobs consumed from the queue and unfinished). Defaults to 10.
This only applies to jobs on the queue in non-blocking mode. MangoX::Queue has an internal counter that is incremented when a job has been consumed from the queue (in non-blocking mode). The job returned is a MangoX::Queue::Job instance and has a descructor method that is called to decrement the internal counter. See MangoX::Queue::Job for more details.
Set to -1 to disable queue concurrency limits. Use with caution, this could result in out of memory errors or an extremely slow event loop.
If you need to decrement the job counter early (e.g. to hold on to a reference to the job after you've finished processing it), you can call the finished method on the MangoX::Queue::Job object.
$job->finished;failed_status
$self->failed_status('Failed');Set a custom failed status.
pending_status
$self->pending_status('Pending');
$self->pending_status(['Pending', 'pending']);Set a custom pending status, can be an array ref.
plugins
my $plugins = $queue->plugins;Returns a hash containing the plugins registered with this queue.
processing_status
$self->processing_status('Processing');Set a custom processing status.
retries
my $retries = $queue->retries;
$queue->retries(5);The number of times a job will be picked up from the queue before it is marked as failed.
timeout
my $timeout = $queue->timeout;
$queue->timeout(10);The time (in seconds) a job is allowed to stay in Retrieved state before it is released back into Pending state. Defaults to 60 seconds.
EVENTS
MangoX::Queue inherits from Mojo::EventEmitter and emits the following events.
Events are emitted only for actions on the current queue object, not the entire queue.
consumed
on $queue consumed => sub {
my ($queue, $job) = @_;
# ...
};Emitted when an item is consumed (either via consume or fetch)
dequeued
on $queue dequeued => sub {
my ($queue, $job) = @_;
# ...
};Emitted when an item is dequeued
enqueued
on $queue enqueued => sub {
my ($queue, $job) = @_;
# ...
};Emitted when an item is enqueued
concurrent_job_limit_reached
on $queue enqueued => sub {
my ($queue, $concurrent_job_limit) = @_;
# ...
};Emitted when a job is found but the </concurrent_job_limit> limit has been reached.
METHODS
MangoX::Queue implements the following methods.
consume
# In blocking mode
while(my $job = consume $queue) {
# ...
}
# In non-blocking mode
consume $queue sub {
my ($job) = @_;
# ...
};Waits for jobs to arrive on the queue, sleeping between queue checks using MangoX::Queue::Delay or Mojo::IOLoop.
Currently sets the status to 'Retrieved' before returning the job.
dequeue
my $job = fetch $queue;
dequeue $queue $job;Dequeues a job. Currently removes it from the collection.
enqueue
my $id = enqueue $queue 'job name';
my $id = enqueue $queue [ 'some', 'data' ];
my $id = enqueue $queue +{ foo => 'bar' };Add an item to the queue in blocking mode. The default priority is 1 and status is 'Pending'.
You can set queue options including priority, created and status.
my $id = enqueue $queue,
priority => 1,
created => bson_time,
status => 'Pending',
+{
foo => 'bar'
};For non-blocking mode, pass in a coderef as the final argument.
my $id = enqueue $queue 'job_name' => sub {
# ...
};
my $id = enqueue $queue priority => 1, +{
foo => 'bar',
} => sub {
# ...
};Sets the status to 'Pending' by default.
fetch
# In blocking mode
my $job = fetch $queue;
# In non-blocking mode
fetch $queue sub {
my ($job) = @_;
# ...
};Fetch a single job from the queue, returning undef if no jobs are available.
Currently sets job status to 'Retrieved'.
get
# In non-blocking mode
get $queue $id => sub {
my ($job) = @_;
# ...
};
# In blocking mode
my $job = get $queue $id;Gets a job from the queue by ID. Doesn't change the job status.
You can also pass in a job instead of an ID.
$job = get $queue $job;get_options
my $options = $queue->get_options;Returns the Mango::Collection options hash used by find_and_modify to identify and update available queue items.
release
my $consumer = consume $queue sub {
# ...
};
release $queue $consumer;Releases a non-blocking consumer from watching a queue.
requeue
my $job = fetch $queue;
requeue $queue $job;Requeues a job. Sets the job status to 'Pending'.
update
my $job = fetch $queue;
$job->{status} = 'Failed';
update $queue $job;Updates a job in the queue.
watch
Wait for a job to enter a certain status.
# In blocking mode
my $id = enqueue $queue 'test';
watch $queue $id, 'Complete'; # blocks until job is complete
# In non-blocking mode
my $id = enqueue $queue 'test';
watch $queue $id, 'Complete' => sub {
# ...
};FUTURE JOBS
Jobs can be queued in advance by setting a delay_until attribute:
enqueue $queue delay_until => (time + 20), "job name";ERRORS
Errors are reported by MangoX::Queue using callbacks and Mojo::EventEmitter
To listen for all errors on a queue, subscribe to the 'error' event:
$queue->on(error => sub {
my ($queue, $job, $error) = @_;
# ...
});To check for errors against an individual update, enqueue or dequeue call, you can check for an error argument to the callback sub:
enqueue $queue +$job => sub {
my ($job, $error) = @_;
if($error) {
# ...
}
}