Minion - Job queue


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']);

# Start a worker to perform up to 12 jobs concurrently
my $worker = $minion->worker;
$worker->status->{jobs} = 12;



Minion is a high performance job queue for the Perl programming language, 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, Mojolicious admin ui, 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 of web applications. 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.


You can use Minion as a standalone job queue or integrate it into Mojolicious applications with the plugin Mojolicious::Plugin::Minion.

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->log->debug('We have poked for a visitor');

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


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

$ ./ minion worker

The worker process will fork a new process for every job that is being processed. This allows for resources such as memory to be returned to the operating system once a job is finished. Perl fork is very fast, so don't worry about the overhead.

|- Minion::Job [1]
|- Minion::Job [2]
+- ...

By default up to four jobs will be processed in parallel, but that can be changed with configuration options or on demand with signals.

$ ./ minion worker -j 12

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

$ ./ minion job

You can also add an admin ui to your application by loading the plugin Mojolicious::Plugin::Minion::Admin. Just make sure to secure access before making your application publically accessible.

# Make admin ui available under "/minion"
plugin 'Minion::Admin';

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

Description=My Mojolicious application workers

ExecStart=/home/sri/myapp/ minion worker -m production


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".


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->log->debug('We have poked for a visitor');


Which are loaded like any other plugin from your application.

# Mojolicious

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


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.


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


$minion->on(enqueue => sub {
  my ($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.";


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

Emitted in the worker process after it has been created.

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


Minion implements the following attributes.


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

Application for job queue, defaults to a Mojo::HelloWorld object. Note that this attribute is weakened.


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

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


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);


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).


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). It is not recommended to set this value below 2 days.


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

Registered tasks.


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


$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};


my $bool = $minion->broadcast('some_command');
my $bool = $minion->broadcast('some_command', [@args]);
my $bool = $minion->broadcast('some_command', [@args], [$id1, $id2, $id3]);

Broadcast remote control command to one or more workers.

# Broadcast "stop" command to all workers to kill job 10025
$minion->broadcast('stop', [10025]);

# Broadcast "kill" command to all workers to interrupt job 10026
$minion->broadcast('kill', ['INT', 10026]);

# Broadcast "jobs" command to pause worker 23
$minion->broadcast('jobs', [0], [23]);


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 => 25

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

delay => 10

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

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 => [$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 => 5

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

queue => 'important'

Queue to put job in, defaults to default.


my $bool = $minion->foreground($id);

Retry job in minion_foreground queue, then perform it right away with a temporary worker in this process, very useful for debugging.


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

Same as "lock", but returns a scope guard object that automatically releases the lock as soon as the object is destroyed, or undef if aquiring the lock failed.

# 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 my $guard = $minion->guard('fragile_backend_service', 7200);

# Only five jobs should run at a time and we try again later if necessary
$minion->add_task(do_concurrent_stuff => sub {
  my ($job, @args) = @_;
  return $job->retry({delay => 30})
    unless my $guard = $minion->guard('some_web_service', 60, {limit => 5});


my $history = $minion->history;

Get history information for job queue.

These fields are currently available:

daily => [{epoch => 12345, finished_jobs => 95, failed_jobs => 2}, ...]

Hourly counts for processed jobs from the past day.


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};


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. For convenience you can also use "guard" to release the lock automatically, even if the job failed.

# 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);

# 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});

# 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});

An expiration time of 0 can be used to check if a named lock already exists without creating one.

# Check if the lock "foo" already exists
say 'Lock exists' unless $minion->lock('foo', 0);

These options are currently available:

limit => 20

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


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

Construct a new Minion object.


$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 }

These options are currently available:

queues => ['important']

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


$minion = $minion->repair;

Repair worker registry and job queue if necessary.


$minion = $minion->reset({all => 1});

Reset job queue.

These options are currently available:

all => 1

Reset everything.

locks => 1

Reset only locks.


my $promise = $minion->result_p($id);
my $promise = $minion->result_p($id, {interval => 5});

Return a Mojo::Promise object for the result of a job. The state finished will result in the promise being fullfilled, and the state failed in the promise being rejected. This operation can be cancelled by resolving the promise manually at any time.

# Enqueue job and receive the result at some point in the future
my $id = $minion->enqueue('foo');
$minion->result_p($id)->then(sub {
  my $info   = shift;
  my $result = ref $info ? $info->{result} : 'Job already removed';
  say "Finished: $result";
})->catch(sub {
  my $info = shift;
  say "Failed: $info->{result}";

These options are currently available:

interval => 5

Polling interval in seconds for checking if the state of the job has changed, defaults to 3.


my $stats = $minion->stats;

Get statistics for the job queue.

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

These fields are currently available:

active_jobs => 100

Number of jobs in active state.

active_locks => 100

Number of active named locks.

active_workers => 100

Number of workers that are currently processing a job.

delayed_jobs => 100

Number of jobs in inactive state that are scheduled to run at specific time in the future or have unresolved dependencies.

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 => 100

Number of jobs in failed state.

finished_jobs => 100

Number of jobs in finished state.

inactive_jobs => 100

Number of jobs in inactive state.

inactive_workers => 100

Number of workers that are currently not processing a job.

uptime => 1000

Uptime in seconds.


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

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


my $worker = $minion->worker;

Build Minion::Worker object. Note that this method should only be used to implement custom workers.

# Use the standard worker with all its features
my $worker = $minion->worker;
$worker->status->{jobs} = 12;
$worker->status->{queues} = ['important'];

# Perform one job manually in a separate process
my $worker = $minion->repair->worker->register;
my $job    = $worker->dequeue(5);

# Perform one job manually in this process
my $worker = $minion->repair->worker->register;
my $job    = $worker->dequeue(5);
if (my $err = $job->execute) { $job->fail($err) }
else                         { $job->finish }

# Build a custom worker performing multiple jobs at the same time
my %jobs;
my $worker = $minion->repair->worker->register;
do {
  for my $id (keys %jobs) {
    delete $jobs{$id} if $jobs{$id}->is_finished;
  if (keys %jobs >= 4) { sleep 5 }
  else {
    my $job = $worker->dequeue(5);
    $jobs{$job->id} = $job->start if $job;
} while keys %jobs;


This is the class hierarchy of the Minion distribution.


The Minion distribution includes a few files with different licenses that have been bundled for internal use.

Minion Artwork

Copyright (C) 2017, Sebastian Riedel.

Licensed under the CC-SA License, Version 4.0


Copyright (C) 2011-2018 The Bootstrap Authors.

Licensed under the MIT License,


Copyright (C) 2010-2016, Michael Bostock.

Licensed under the 3-Clause BSD License,


Copyright (C) 2014 Fastly, Inc.

Licensed under the MIT License,

Font Awesome

Copyright (C) Dave Gandy.

Licensed under the MIT License,, and the SIL OFL 1.1,


Copyright (C) JS Foundation and other contributors.

Licensed under the MIT License,


Copyright (C) Federico Zivolo 2017.

Licensed under the MIT License,


Sebastian Riedel,


In alphabetical order:


Copyright (C) 2014-2019, 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, Mojolicious::Guides,