# SidekiqUniqueJobs [![Build Status](https://travis-ci.org/mhenrixon/sidekiq-unique-jobs.png?branch=master)](https://travis-ci.org/mhenrixon/sidekiq-unique-jobs) [![Code Climate](https://codeclimate.com/github/mhenrixon/sidekiq-unique-jobs.png)](https://codeclimate.com/github/mhenrixon/sidekiq-unique-jobs) [![Test Coverage](https://codeclimate.com/github/mhenrixon/sidekiq-unique-jobs/badges/coverage.svg)](https://codeclimate.com/github/mhenrixon/sidekiq-unique-jobs/coverage)

The missing unique jobs for sidekiq

## Requirements

See https://github.com/mperham/sidekiq#requirements for what is required. Starting from 3.0.13 only sidekiq 3 is supported and support for MRI 1.9 is dropped (it might work but won't be worked on)

### Version 4 Upgrade instructions

Version 4 requires redis >= 2.6.2!! Don't upgrade to version 4 unless you are on redis >= 2.6.2.

Easy path - Drop all your unique jobs before upgrading the gem!

Hard path - See below... Start with a clean slate :)

## Installation

Add this line to your application's Gemfile:

    gem 'sidekiq-unique-jobs'

And then execute:

    $ bundle

Or install it yourself as:

    $ gem install sidekiq-unique-jobs

## Locking

Like @mperham mentions on [this wiki page](https://github.com/mperham/sidekiq/wiki/Related-Projects#unique-jobs) it is hard to enforce uniqueness with redis in a distributed redis setting.

To make things worse there are many ways of wanting to enforce uniqueness.

### While Executing

Due to discoverability of the different lock types `unique` sidekiq option it was decided to use the `while_executing` as a default. Most people will note that scheduling any number of jobs with the same arguments is possible.

```ruby
sidekiq_options unique: :while_executing
```

Is to make sure that a job can be scheduled any number of times but only executed a single time per argument provided to the job we call this runtime uniqueness. This is probably most useful forbackground jobs that are fast to execute. (See mhenrixon/sidekiq-unique-jobs#111 for a great example of when this would be right.) While the job is executing/performing no other jobs can be executed at the same time.

### Until Executing

```ruby
sidekiq_options unique: :until_executing
```

This means that a job can only be scheduled into redis once per whatever the configuration of unique arguments. Any jobs added until the first one of the same arguments has been unlocked will just be dropped. This is what was tripping many people up. They would schedule a job to run in the future and it would be impossible to schedule new jobs with those same arguments even immediately. There was some forth and back between also locking jobs on the scheduled queue and the regular queues but in the end I decided it was best to separate these two features out into different locking mechanisms. I think what most people are after is to be able to lock a job while executing or that seems to be what people are most missing at the moment.

### Until Executed

```ruby
sidekiq_options unique: :until_executed
```

This is the combination of the two above. First we lock the job until it executes, then as the job begins executes we keep the lock so that no other jobs with the same arguments can execute at the same time.

### Until Timeout

```ruby
sidekiq_options unique: :until_timeout
```

The job won't be unlocked until the timeout/expiry runs out.

### Unique Until And While Executing

```ruby
sidekiq_options unique: :until_and_while_executing
```

This lock is exactly what you would expect. It is considered unique in a way until executing begins and it is locked while executing so what differs from `UntilExecuted`?

The difference is that this job has two types of uniqueness:
1. It is unique until execution
2. It is unique while executing

That means it locks for any job with the same arguments to be persisted into redis and just like you would expect it will only ever allow one job of the same unique arguments to run at any given time but as soon as the runtime lock has been aquired the schedule/async lock is released.

### Uniqueness Scope

- Queue specific locks
- Across all queues.
- Timed / Scheduled jobs

## Usage

All that is required is that you specifically set the sidekiq option for *unique* to a valid value like below:

```ruby
sidekiq_options unique: :while_executing
```

For jobs scheduled in the future it is possible to set for how long the job
should be unique. The job will be unique for the number of seconds configured (default 30 minutes)
or until the job has been completed. Thus, the job will be unique for the shorter of the two.  Note that Sidekiq versions before 3.0 will remove job keys after an hour, which means jobs can remain unique for at most an hour.

*If you want the unique job to stick around even after it has been successfully
processed then just set `unique: :until_timeout`.

You can also control the expiration length of the uniqueness check. If you want to enforce uniqueness over a longer period than the default of 30 minutes then you can pass the number of seconds you want to use to the sidekiq options:

```ruby
sidekiq_options unique: :until_timeout, unique_expiration: 120 * 60 # 2 hours
```

Requiring the gem in your gemfile should be sufficient to enable unique jobs.

### Usage with ActiveJob

```ruby
Sidekiq.default_worker_options = {
  unique: :until_executing,
  unique_args: ->(args) { args.first.except('job_id') }
}
```


### Finer Control over Uniqueness

Sometimes it is desired to have a finer control over which arguments are used in determining uniqueness of the job, and others may be _transient_. For this use-case, you need to define either a `unique_args` method, or a ruby proc.

The unique_args method need to return an array of values to use for uniqueness check.

The method or the proc can return a modified version of args without the transient arguments included, as shown below:

```ruby
class UniqueJobWithFilterMethod
  include Sidekiq::Worker
  sidekiq_options unique: :until_and_during_execution,
                  unique_args: :unique_args

  def self.unique_args(name, id, options)
    [ name, options[:type] ]
  end

  ...

end

class UniqueJobWithFilterProc
  include Sidekiq::Worker
  sidekiq_options unique: :until_executed,
                  unique_args: ->(args) { [ args.first ] }

  ...

end
```

The previous problems with unique args being string in server and symbol in client is no longer a problem because the `UniqueArgs` class accounts for this and converts everything to json now. If you find an edge case please provide and example so that we can add coverage and fix it.

### After Unlock Callback

If you are using :after_yield as your unlock ordering, Unique Job offers a callback to perform some work after the block is yielded.

```ruby
class UniqueJobWithFilterMethod
  include Sidekiq::Worker
  sidekiq_options unique: :while_executing,

  def after_unlock
   # block has yielded and lock is released
  end
  ...
end.

```

### Logging

To see logging in sidekiq when duplicate payload has been filtered out you can enable on a per worker basis using the sidekiq options.  The default value is false

```ruby
class UniqueJobWithFilterMethod
  include Sidekiq::Worker
  sidekiq_options unique: :while_executing,
                  log_duplicate_payload: true

  ...

end
```

## Debugging
There are two ways to display and remove keys regarding uniqueness. The console way and the command line way.

### Console
Start the console with the following command `bundle exec jobs console`.

#### List Unique Keys
`keys '*', count: 100`

#### Remove Unique Keys
`del_by '*', count: 100, dry_run: false` the dry_run and count parameters are both required. This is to have some type of protection against clearing out all uniqueness.

### Command Line

`bundle exec jobs` displays help on how to use the unique jobs command line.


## Testing

To enable the testing for `sidekiq-unique-jobs`, add `require 'sidekiq_unique_jobs/testing'` to your testing helper.

## Contributing

1. Fork it
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request

## Contributors

- https://github.com/salrepe
- https://github.com/rickenharp
- https://github.com/sax
- https://github.com/eduardosasso
- https://github.com/KensoDev
- https://github.com/adstage-david
- https://github.com/jprincipe
- https://github.com/crberube
- https://github.com/simonoff