/ 
Minion-7.03
River stage two • 21 direct dependents • 30 total dependents
/ Minion

NAME

Minion - Job queue

SYNOPSIS

use Minion;

# Connect to backend
my $minion = Minion->new(Pg => 'postgresql://postgres@/test');

# Add tasks
$minion->add_task(something_slow => sub {
  my ($job, @args) = @_;
  sleep 5;
  say 'This is a background worker process.';
});

# Enqueue jobs
$minion->enqueue(something_slow => ['foo', 'bar']);
$minion->enqueue(something_slow => [1, 2, 3] => {priority => 5});

# Perform jobs for testing
$minion->enqueue(something_slow => ['foo', 'bar']);
$minion->perform_jobs;

# Build more sophisticated workers
my $worker = $minion->repair->worker;
while (int rand 2) {
  if (my $job = $worker->register->dequeue(5)) { $job->perform }
}
$worker->unregister;

DESCRIPTION

Minion is a job queue for the Mojolicious real-time web framework, with support for multiple named queues, priorities, delayed jobs, job dependencies, job progress, job results, retries with backoff, rate limiting, unique jobs, statistics, distributed workers, parallel processing, autoscaling, remote control, resource leak protection and multiple backends (such as PostgreSQL).

Job queues allow you to process time and/or computationally intensive tasks in background processes, outside of the request/response lifecycle. Among those tasks you'll commonly find image resizing, spam filtering, HTTP downloads, building tarballs, warming caches and basically everything else you can imagine that's not super fast.

use Mojolicious::Lite;

plugin Minion => {Pg => 'postgresql://sri:s3cret@localhost/test'};

# Slow task
app->minion->add_task(poke_mojo => sub {
  my $job = shift;
  $job->app->ua->get('mojolicious.org');
  $job->app->log->debug('We have poked mojolicious.org for a visitor');
});

# Perform job in a background worker process
get '/' => sub {
  my $c = shift;
  $c->minion->enqueue('poke_mojo');
  $c->render(text => 'We will poke mojolicious.org for you soon.');
};

app->start;

Background worker processes are usually started with the command Minion::Command::minion::worker, which becomes automatically available when an application loads the plugin Mojolicious::Plugin::Minion.

$ ./myapp.pl minion worker

Jobs can be managed right from the command line with Minion::Command::minion::job.

$ ./myapp.pl minion job

To manage background worker processes with systemd, you can use a unit configuration file like this.

[Unit]
Description=My Mojolicious application workers
After=postgresql.service

[Service]
Type=simple
ExecStart=/home/sri/myapp/myapp.pl minion worker -m production
KillMode=process

[Install]
WantedBy=multi-user.target

Every job can fail or succeed, but not get lost, the system is eventually consistent and will preserve job results for as long as you like, depending on "remove_after". While individual workers can fail in the middle of processing a job, the system will detect this and ensure that no job is left in an uncertain state, depending on "missing_after".

GROWING

And as your application grows, you can move tasks into application specific plugins.

package MyApp::Task::PokeMojo;
use Mojo::Base 'Mojolicious::Plugin';

sub register {
  my ($self, $app) = @_;
  $app->minion->add_task(poke_mojo => sub {
    my $job = shift;
    $job->app->ua->get('mojolicious.org');
    $job->app->log->debug('We have poked mojolicious.org for a visitor');
  });
}

1;

Which are loaded like any other plugin from your application.

# Mojolicious
$app->plugin('MyApp::Task::PokeMojo');

# Mojolicious::Lite
plugin 'MyApp::Task::PokeMojo';

EXAMPLES

This distribution also contains a great example application you can use for inspiration. The link checker will show you how to integrate background jobs into well-structured Mojolicious applications.

EVENTS

Minion inherits all events from Mojo::EventEmitter and can emit the following new ones.

enqueue

$minion->on(enqueue => sub {
  my ($minion, $id) = @_;
  ...
});

Emitted after a job has been enqueued, in the process that enqueued it.

$minion->on(enqueue => sub {
  my ($minion, $id) = @_;
  say "Job $id has been enqueued.";
});

worker

$minion->on(worker => sub {
  my ($minion, $worker) = @_;
  ...
});

Emitted in the worker process after it has been created.

$minion->on(worker => sub {
  my ($minion, $worker) = @_;
  my $id = $worker->id;
  say "Worker $$:$id started.";
});

ATTRIBUTES

Minion implements the following attributes.

app

my $app = $minion->app;
$minion = $minion->app(MyApp->new);

Application for job queue, defaults to a Mojo::HelloWorld object.

backend

my $backend = $minion->backend;
$minion     = $minion->backend(Minion::Backend::Pg->new);

Backend, usually a Minion::Backend::Pg object.

backoff

my $cb  = $minion->backoff;
$minion = $minion->backoff(sub {...});

A callback used to calculate the delay for automatically retried jobs, defaults to (retries ** 4) + 15 (15, 16, 31, 96, 271, 640...), which means that roughly 25 attempts can be made in 21 days.

$minion->backoff(sub {
  my $retries = shift;
  return ($retries ** 4) + 15 + int(rand 30);
});

missing_after

my $after = $minion->missing_after;
$minion   = $minion->missing_after(172800);

Amount of time in seconds after which workers without a heartbeat will be considered missing and removed from the registry by "repair", defaults to 1800 (30 minutes).

remove_after

my $after = $minion->remove_after;
$minion   = $minion->remove_after(86400);

Amount of time in seconds after which jobs that have reached the state finished and have no unresolved dependencies will be removed automatically by "repair", defaults to 172800 (2 days).

tasks

my $tasks = $minion->tasks;
$minion   = $minion->tasks({foo => sub {...}});

Registered tasks.

METHODS

Minion inherits all methods from Mojo::EventEmitter and implements the following new ones.

add_task

$minion = $minion->add_task(foo => sub {...});

Register a task.

# Job with result
$minion->add_task(add => sub {
  my ($job, $first, $second) = @_;
  $job->finish($first + $second);
});
my $id = $minion->enqueue(add => [1, 1]);
my $result = $minion->job($id)->info->{result};

enqueue

my $id = $minion->enqueue('foo');
my $id = $minion->enqueue(foo => [@args]);
my $id = $minion->enqueue(foo => [@args] => {priority => 1});

Enqueue a new job with inactive state. Arguments get serialized by the "backend" (often with Mojo::JSON), so you shouldn't send objects and be careful with binary data, nested data structures with hash and array references are fine though.

These options are currently available:

attempts
attempts => 25

Number of times performing this job will be attempted, with a delay based on "backoff" after the first attempt, defaults to 1.

delay
delay => 10

Delay job for this many seconds (from now), defaults to 0.

notes
notes => {foo => 'bar', baz => [1, 2, 3]}

Hash reference with arbitrary metadata for this job that gets serialized by the "backend" (often with Mojo::JSON), so you shouldn't send objects and be careful with binary data, nested data structures with hash and array references are fine though.

parents
parents => [$id1, $id2, $id3]

One or more existing jobs this job depends on, and that need to have transitioned to the state finished before it can be processed.

priority
priority => 5

Job priority, defaults to 0. Jobs with a higher priority get performed first.

queue
queue => 'important'

Queue to put job in, defaults to default.

job

my $job = $minion->job($id);

Get Minion::Job object without making any changes to the actual job or return undef if job does not exist.

# Check job state
my $state = $minion->job($id)->info->{state};

# Get job metadata
my $progress = $minion->$job($id)->info->{notes}{progress};

# Get job result
my $result = $minion->job($id)->info->{result};

lock

my $bool = $minion->lock('foo', 3600);
my $bool = $minion->lock('foo', 3600, {limit => 20});

Try to acquire a named lock that will expire automatically after the given amount of time in seconds. You can release the lock manually with "unlock" to limit concurrency, or let it expire for rate limiting.

# Only one job should run at a time (unique job)
$minion->add_task(do_unique_stuff => sub {
  my ($job, @args) = @_;
  return $job->finish('Previous job is still active')
    unless $minion->lock('fragile_backend_service', 7200);
  ...
  $minion->unlock('fragile_backend_service');
});

# Only five jobs should run at a time and we wait for our turn
$minion->add_task(do_concurrent_stuff => sub {
  my ($job, @args) = @_;
  sleep 1 until $minion->lock('some_web_service', 60, {limit => 5});
  ...
  $minion->unlock('some_web_service');
});

# Only a hundred jobs should run per hour and we try again later if necessary
$minion->add_task(do_rate_limited_stuff => sub {
  my ($job, @args) = @_;
  return $job->retry({delay => 3600})
    unless $minion->lock('another_web_service', 3600, {limit => 100});
  ...
});

These options are currently available:

limit
limit => 20

Number of shared locks with the same name that can be active at the same time, defaults to 1.

new

my $minion = Minion->new(Pg => 'postgresql://postgres@/test');
my $minion = Minion->new(Pg => Mojo::Pg->new);

Construct a new Minion object.

perform_jobs

$minion->perform_jobs;
$minion->perform_jobs({queues => ['important']});

Perform all jobs with a temporary worker, very useful for testing.

# Longer version
my $worker = $minion->worker;
while (my $job = $worker->register->dequeue(0)) { $job->perform }
$worker->unregister;

These options are currently available:

queues
queues => ['important']

One or more queues to dequeue jobs from, defaults to default.

repair

$minion = $minion->repair;

Repair worker registry and job queue if necessary.

reset

$minion = $minion->reset;

Reset job queue.

stats

my $stats = $minion->stats;

Get statistics for jobs and workers.

# Check idle workers
my $idle = $minion->stats->{inactive_workers};

These fields are currently available:

active_jobs
active_jobs => 100

Number of jobs in active state.

active_workers
active_workers => 100

Number of workers that are currently processing a job.

delayed_jobs
delayed_jobs => 100

Number of jobs in inactive state that are scheduled to run at specific time in the future or have unresolved dependencies. Note that this field is EXPERIMENTAL and might change without warning!

enqueued_jobs
enqueued_jobs => 100000

Rough estimate of how many jobs have ever been enqueued. Note that this field is EXPERIMENTAL and might change without warning!

failed_jobs
failed_jobs => 100

Number of jobs in failed state.

finished_jobs
finished_jobs => 100

Number of jobs in finished state.

inactive_jobs
inactive_jobs => 100

Number of jobs in inactive state.

inactive_workers
inactive_workers => 100

Number of workers that are currently not processing a job.

unlock

my $bool = $minion->unlock('foo');

Release a named lock that has been previously acquired with "lock".

worker

my $worker = $minion->worker;

Build Minion::Worker object.

REFERENCE

This is the class hierarchy of the Minion distribution.

AUTHOR

Sebastian Riedel, sri@cpan.org.

CREDITS

In alphabetical order:

    Andrey Khozov

    Brian Medley

    Hubert "depesz" Lubaczewski

    Joel Berger

    Paul Williams

COPYRIGHT AND LICENSE

Copyright (C) 2014-2017, Sebastian Riedel and others.

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.

SEE ALSO

https://github.com/kraih/minion, Mojolicious::Guides, http://mojolicious.org.