Firebolt

Firebolt is a simple cache warmer. It warms the cache using a specially defined warmer class. It also has an optional file-based warmer to make boot-time fast!

It's not quite ready for Prime Time™ and needs specs (YIKES!). Feel free add some, if you like...

Installation

Add this line to your application's Gemfile:

gem 'firebolt'

And then execute:

$ bundle

Or install it yourself as:

$ gem install firebolt

Usage

To use Firebolt, you first need to configure it.

Configure & Initialize!

::Firebolt.configure do |config|
  # Required
  config.cache = ::Rails.cache # Or anything that adheres to Rails's cache interface
  config.warming_frequency = 12.hours # In seconds. Get minutes/hours/days helper w/ ActiveSupport
  config.warmer = ::YourAwesomeCacheWarmer

  # Optional
  config.cache_file_enabled = true
  config.cache_file_path = '/path/to/your/project/tmp' # Defaults to /tmp
end

Then you need to initialize it:

# Calling initialize! starts the warming cycle.
# It's best to skip the warming cycle while running specs. Warming is
# automatically skipped while running specs in Rails apps. In other apps, set
# FIREBOLT_SKIP_WARMING to true (or 1, or 'sandwich').
::Firebolt.initialize!

# Also takes a block so you can initialize and configure at the same time:
::Firebolt.initialize! do |config|
  config.cache = ::Rails.cache
  config.warming_frequency = 12.hours
  config.warmer = ::YourAwesomeCacheWarmer
end

Reading cached data

Firebolt provides two methods for retrieving cached data: Firebolt.read & Firebolt.fetch.

Firebolt.read takes your cache key and return the value from the cache.

Firebolt.fetch does the same thing, but also takes an optional block that is called when there is a cache miss.

Warming the cache

Firebolt uses a cache warmer that you create. Valid cache warmers must:

Include Firebolt::Warmer
Define a perform method that returns a hash

Here's an example:

class YourAwesomeCacheWarmer
  include ::Firebolt::Warmer

  def perform
    # Returns a hash. The keys become the cache keys and the values become cache values.
  end
end

Firebolt uses this warmer to re-warm the cache at the frequency you configure (e.g. config.warming_frequency). If it's set to re-warm every 12 hours, Firebolt will warm the cache every twelve hours.

Under the hood, Firebolt keeps track of the current cache set. That way, it's able to warm a new cache set and swap it with the old cache set in place, avoiding cache misses.

The file warmer

Firebolt is built to be fast and unobtrusive, but sometimes warming a cache can take some time. That's where the file warmer comes in. When the file warmer is enabled, after warming the cache, Firebolt will write the cached data to a file. The next time your app starts up, it will warm the cache from the file. Each subsequent warming happens with your custom warmer.

To use file warmer, simply set the cache_file_enabled and cache_file_path config options.

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request