BatchQueue

BatchQueue is queue that takes jobs and runs them, in aggregate, via a callback on a background thread. You can process a “batch” of N jobs at a time or after T seconds whichever comes sooner.

Example

You want to send metrics to Amazon’s AWS CloudWatch service every 60 seconds or when the batch size reaches 20, whichever comes first. You might write code like this:

# Create the AWS CloudWatch Client
cw_client = Aws::CloudWatch::Client.new(...)

# Set up the BatchQueue
BatchQueue.new(max_batch_size: 20, max_interval_seconds: 60) do |batch_metric_data|
    cw_client.put_metric_data(:metric_data => batch_metric_data)
end

# Add to the BatchQueue
@bq << {
    metric_name: 'Widgets',
    value: 1
}

Installation

Add this line to your application's Gemfile:

gem 'batch_queue'

And then execute:

$ bundle

Or install it yourself as:

$ gem install batch_queue

Usage

1. Set up the BatchQueue

Each BatchQueue gets its own background thread that executes jobs.

bq = BatchQueue.new(max_batch_size: 20, max_interval_seconds: 60) do |batch_metric_data|
    # Put your code that you want to execute here.
end

2. Add a job to the queue

You can add any object to the queue.

bq << {
    # your object here.
}

or

bq << MyJob.new(...)

3. Error handling

You have two options for handling errors in BatchQueue:

• Rescue exceptions within the processing block:

  bq = BatchQueue.new(max_batch_size: 20, max_interval_seconds: 60) do |batch_metric_data|
    begin
        # Put your code that you want to execute here.
    rescue => e
        # Handle the exception here.
    end
  end

• Set a global error handler:

  bq.on_error = ->(e) { puts e.message }

If neither method is used, BatchQueue will catch the exception and print it to the standard console output.

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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/flivni/batch_queue.

License

The gem is available as open source under the terms of the MIT License.