deanpcmad--sidekiq-limit_fetch/README.md

## Description

Sidekiq strategy to restrict number of workers
which are able to run specified queues simultaneously.

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## Installation

Add this line to your application's Gemfile:

    gem 'sidekiq-limit_fetch'

## Usage

### Limits

Specify limits which you want to place on queues inside sidekiq.yml:

```yaml
  :limits:
    queue_name1: 5
    queue_name2: 10
```

Or set it dynamically in your code:
```ruby
  Sidekiq::Queue['queue_name1'].limit = 5
  Sidekiq::Queue['queue_name2'].limit = 10
```

In these examples, tasks for the ```queue_name1``` will be run by at most 5
workers at the same time and the ```queue_name2``` will have no more than 10
workers simultaneously.

Ability to set limits dynamically allows you to resize worker
distribution among queues any time you want.


### Pauses

You can also pause your queues temporarely. Upon continuing their limits
will be preserved.

```ruby
  Sidekiq::Queue['name'].pause # prevents workers from running tasks from this queue
  Sidekiq::Queue['name'].paused? # => true
  Sidekiq::Queue['name'].unpause # allows workers to use the queue
```


You can see how many workers currently handling a queue:

```ruby
  Sidekiq::Queue['name'].busy # number of busy workers
```

### Multiple processes

Limits are applied per process. In case you have several worker
processes and want to have global locks between them, you'll need to
enable global mode by setting global option, eg:

```yaml
  :global: true
```

or

```ruby
  Sidekiq.options[:global] = true
```


### Blocking queue mode

If you use strict queue ordering (it will be used if you don't specify queue weights)
then you can set blocking status for queues. It means if a blocking
queue task is executing then no new task from lesser priority queues will
be ran. Eg,

```yaml
  :queues:
    - a
    - b
    - c
  :blocking:
    - b
```

In this case when a task for `b` queue is ran no new task from `c` queue
will be started.

You can also enable and disable blocking mode for queues on the fly:

```ruby
  Sidekiq::Queue['name'].block
  Sidekiq::Queue['name'].blocking? # => true
  Sidekiq::Queue['name'].unblock
```


### Thanks

Sponsored by [Evil Martians].
[Evil Martians]: http://evilmartians.com/