README.md
# ActiveJob::TrafficControl [](https://travis-ci.org/nickelser/activejob-traffic_control) [](https://codeclimate.com/github/nickelser/activejob-traffic_control) [](https://codeclimate.com/github/nickelser/activejob-traffic_control) [](http://badge.fury.io/rb/activejob-traffic_control)
Rate controls for your `ActiveJob`s, powered by [Suo](https://github.com/nickelser/suo), a distributed semaphore library backed by Redis or Memcached.
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'activejob-traffic_control'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install activejob-traffic_control
## Usage
`ActiveJob::TrafficControl` adds three modules you can mixin to your job classes as needed, or to `ApplicationJob` if you are using ActiveJob 5+ (or you have created a base job class yourself).
```ruby
# to initialize the type of locking client (memcached vs. redis):
ActiveJob::TrafficControl.client = ConnectionPool.new(size: 5, timeout: 5) { Redis.new } # set poolthresholds as needed
# or, ActiveJob::TrafficControl.client = ConnectionPool.new(size: 5, timeout: 5) { Dalli::Client.new }
# or if not multithreaded, ActiveJob::TrafficControl.client = Redis.new
```
### `Throttle`
```ruby
class CanThrottleJob < ActiveJob::Base
throttle threshold: 2, period: 1.second
def perform
# no more than two of `CanThrottleJob` will run every second
# if more than that attempt to run, they will be re-enqueued to run in a random time
# ranging from 1 - 5x the period (so, 1-5 seconds in this case)
end
end
```
If you do not care about the job being re-enqueued (if it's scheduled to run otherwise, or dropping will have no ill effect), you can specify `drop: true` instead. The `drop: true` flag also applies to `Concurrency`, below.
```ruby
class CanThrottleAndDropJob < ActiveJob::Base
throttle threshold: 2, period: 1.second, drop: true
def perform
# no more than two of `CanThrottleJob` will run every second
# if more than that attempt to run, they will be dropped
end
end
```
### `Concurrency`
```ruby
class ConcurrencyTestJob < ActiveJob::Base
concurrency 5, drop: false
def perform
# only five `ConcurrencyTestJob` will ever run simultaneously
end
end
```
### `Disable`
For `Disable`, you also need to configure the cache client:
```ruby
ActiveJob::TrafficControl.cache_client = Rails.cache.dalli # if using :dalli_store
# or ActiveJob::TrafficControl.cache_client = ActiveSupport::Cache.lookup_store(:dalli_store, "localhost:11211")
```
```ruby
class CanDisableJob < ActiveJob::Base
def perform
# you can pause this job from running by executing `CanDisableJob.disable!` (which will cause the job to be re-enqueued),
# or have it be dropped entirely via `CanDisableJob.disable!(drop: true)`
# enable it again via `CanDisableJob.enable!`
end
end
```
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/nickelser/activejob-traffic_control. Please look at the `.rubocop.yml` for the style guide.