Class: Moneta::Fallback

Inherits:
Wrapper show all
Defined in:
lib/moneta/fallback.rb

Overview

Provides a fallback to a second store when an exception is raised

Examples:

Basic usage - catches any IOError and falls back to Adapters:Null

Moneta.build do
  use :Fallback
  adapter :Client
end

Specifying an exception to rescue

Moneta.build do
  use :Fallback, rescue: Redis::CannotConnectError
  adapter :Redis
end

Specifying a different fallback

Moneta.build do
  use :Fallback do
    # This is a new builder context
    adapter :Memory
  end
  adapter :File, dir: 'cache'
end

Instance Attribute Summary

Attributes inherited from Proxy

#adapter

Instance Method Summary collapse

Methods inherited from Wrapper

#clear, #close, #create, #delete, #each_key, #features, #fetch_values, #increment, #key?, #load, #merge!, #slice, #store, #values_at

Methods inherited from Proxy

#clear, #close, #create, #delete, #each_key, #features, features_mask, #fetch_values, #increment, #key?, #load, #merge!, not_supports, #slice, #store, #values_at

Methods included from Defaults

#[], #[]=, #close, #create, #decrement, #each_key, #features, #fetch, #fetch_values, included, #increment, #key?, #merge!, #slice, #supports?, #update, #values_at

Methods included from OptionSupport

#expires, #prefix, #raw, #with

Constructor Details

#initialize(adapter, options = {}, &block) ⇒ Fallback

Returns a new instance of Fallback.

Parameters:

  • adapter (Moneta store)

    The underlying store

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :fallback (Moneta store) — default: :Null store

    The store to fall back on

  • :rescue (Class|Array<Class>) — default: [IOError]

    The list of exceptions that should be rescued

Yield Returns:

  • (Moneta store)

    Moneta store built using the builder API


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# File 'lib/moneta/fallback.rb', line 34

def initialize(adapter, options = {}, &block)
  super

  @fallback =
    if block_given?
      ::Moneta.build(&block)
    elsif options.key?(:fallback)
      options.delete(:fallback)
    else
      ::Moneta::Adapters::Null.new
    end

  @rescue =
    case options[:rescue]
    when nil
      [::IOError]
    when Array
      options[:rescue]
    else
      [options[:rescue]]
    end
end