MangoX::Queue - A MongoDB queue implementation using Mango
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.
API change - the current API is inconsistent with Mojo::IOLoop and other Mojolicious modules. A delay_compat option has been added, which is currently disabled by default. This will be enabled by default in a future release, and eventually deprecated.
delay_compat
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) = @_; };
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) { # ... }
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';
MangoX::Queue implements the following attributes.
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.
my $delay = $queue->delay; $queue->delay(MangoX::Queue::Delay->new);
The MangoX::Queue::Delay responsible for dynamically controlling the delay between queue queries.
my $compat = $queue->delay_compat; $queue->delay_compat(1);
Enabling delay_compat passes $self as the first argument to queue callbacks, to fix a compatibility bug with Mojo::IOLoop.
$self
This will be enabled by default in a future release. Please migrate your code to work with the new API, and enable delay_compat on construction:
my $queue = MangoX::Queue->new(delay_compat => 1);
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.
finished
$job->finished;
$self->failed_status('Failed');
Set a custom failed status.
$no_bin = $self->no_binary_oid; $self->no_binary_oid(1);
Set to 1 to disable binary ObjectIDs being returned by MangoX::Queue in the Job object.
$self->pending_status('Pending'); $self->pending_status(['Pending', 'pending']);
Set a custom pending status, can be an array ref.
my $plugins = $queue->plugins;
Returns a hash containing the plugins registered with this queue.
$self->processing_status('Processing');
Set a custom processing status.
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.
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.
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.
on $queue consumed => sub { my ($queue, $job) = @_; # ... };
Emitted when an item is consumed (either via consume or fetch)
on $queue dequeued => sub { my ($queue, $job) = @_; # ... };
Emitted when an item is dequeued
on $queue enqueued => sub { my ($queue, $job) = @_; # ... };
Emitted when an item is enqueued
on $queue enqueued => sub { my ($queue, $concurrent_job_limit) = @_; # ... };
Emitted when a job is found but the </concurrent_job_limit> limit has been reached.
MangoX::Queue implements the following methods.
# 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.
my $job = fetch $queue; dequeue $queue $job;
Dequeues a job. Currently removes it from the collection.
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.
# 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'.
# 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;
my $options = $queue->get_options;
Returns the Mango::Collection options hash used by find_and_modify to identify and update available queue items.
my $consumer = consume $queue sub { # ... }; release $queue $consumer;
Releases a non-blocking consumer from watching a queue.
my $job = fetch $queue; requeue $queue $job;
Requeues a job. Sets the job status to 'Pending'.
my $job = fetch $queue; $job->{status} = 'Failed'; update $queue $job;
Updates a job in the queue.
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 { # ... };
Jobs can be queued in advance by setting a delay_until attribute:
enqueue $queue delay_until => (time + 20), "job name";
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) { # ... } }
MangoX::Queue::Tutorial, Mojolicious, Mango
To install MangoX::Queue, copy and paste the appropriate command in to your terminal.
cpanm
cpanm MangoX::Queue
CPAN shell
perl -MCPAN -e shell install MangoX::Queue
For more information on module installation, please visit the detailed CPAN module installation guide.