Cache JSON

This gem lets you easily cache the results of any computation to Redis. The cache is automatically populated when the results method is called.

The cache expires after a specified time, unless you explicitly clear it before that. You can use the provided Sidekiq job to periodically refresh the cache.

Add this line to your application's Gemfile:

gem 'cache_json'

And then execute:

$ bundle

Or install it yourself as:

$ gem install cache_json

All you need is a class with a compute_results method (make sure you use keyword arguments):

class ExpensiveJob

  include CacheJSON::Base

  cache_json_options(
    time_to_expire: 1.hour, # Specify how long the cache lives
  )

  def compute_results(first_arg:, second_arg:)
    # Compute some stuff and return the results
    # The results will then be cached *for those specific arguments*
  end
end

# If the cache exists, return it. Otherwise, populate it and return it
ExpensiveJob.new.results(first_arg: "foo", second_arg: "bar")

# Clear the cache for all arguments
ExpensiveJob.new.clear_cache!

If you'd like to specify some global defaults, you can put them in config/initializers/cache_json.rb

CacheJSON.configure do |config|
  config.time_to_expire = 6.hours
end

There is a simple Sidekiq job that lets you pre-compute selected classes with specified ranges of arguments. All you have to do is add a refresh option:

class ExpensiveJob

  include CacheJSON::Base


  cache_json_options(
    time_to_expire: 1.hour,
    refresh: {
      buffer: 5.minutes,
      arguments: {
        first: (5..10),
        second: ['one option', 'another option'],
        third: 'the only option',
        fourth: -> { ['proc result'] }
      }
    }
  )
  ...
end

The Sidekiq job will take the Cartesian product of all the argument ranges/arrays (all the combinations).

We leave it to you to schedule the job. If you're using https://github.com/moove-it/sidekiq-scheduler, you can do something like this:

cache_json_worker:
  every: "20s"
  class: CacheJSON::Worker

Whenever the worker runs, it checks which results have expired, and refreshes only those. If you pass in the buffer option, it will actually refresh keys that are that far away from expiring. In the example above, the worker will refresh the cache 5 minutes before it expires. This is good if you want to avoid cache misses altogether.

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

Bug reports and pull requests are welcome on GitHub at https://github.com/loopsupport/cache_json. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

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

Everyone interacting in the CacheJSON project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.