BarkingIguana::CacheBucket

Provides a naive but easy to set up cache with time based expiry.

Time based expiry in implemented as a maximum age that the cached objects may reach. It's not a guarantee that the objects will live that long.

Add this line to your application's Gemfile:

gem 'barking_iguana-cache_bucket'

And then execute:

$ bundle

Or install it yourself as:

$ gem install barking_iguana-cache_bucket

Most likely you'll want to use the DSL in your class:

require 'barking_iguana/cache_bucket'

class Thing
  include BarkingIguana::CacheBucket::DSL

  def expensive_operation
    cache_bucket.get 'expensive_operation' do
      object_id
    end
  end
end

BEWARE! The cache will persist across instances of the class:

# Create two new instances of the class
t1 = Thing.new
t2 = Thing.new

# These have different object ids:
t1.object_id #=> 70248246472260
t2.object_id #=> 70248259056820

# But the same value is returned from both:
t1.expensive_operation #=> 70248246472260
t2.expensive_operation #=> 70248246472260

If you need CacheBuckets that are scoped to instances you should use a prefix:

class ScopedThing
  include BarkingIguana::CacheBucket::DSL

  def expensive_operation
    cache_bucket.get 'expensive_operation', prefix: "instance_#{id}" do
      object_id
    end
  end
end

# Create two new instances of the class
s1 = ScopedThing.new
s2 = ScopedThing.new

# These have different object ids:
s1.object_id #=> 70248246472260
s2.object_id #=> 70248259056820

# Now a different value is returned from both:
s1.expensive_operation #=> 70248246472260
s2.expensive_operation #=> 70248259056820

You may configure a few things about the behaviour of the CacheBuckets.

BarkingIguana::CacheBucket.logger = Logger.new($stdout)

It logs at Logger::DEBUG, so you won't see very much unless you crank the log level of your logger way up.

The default is 3600 seconds - one hour. You can set it to any number of seconds though. Please note that I only support integer numbers of seconds.

BarkingIguana::CacheBucket.maximum_age = 7200

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.

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.

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