kjg / carrierwave-cascade

Retrieve from a secondary storage when the file is not in the primary storage.

Carrierwave::Cascade

A storage plugin for carrierwave that will retrieving files from a secondary storage if the file is not present in the primary storage. New files will always be stored in the primary storage. This is perfect for use while migrating from one storage to another, or to avoid polluting a production environment when running a staging mirror.

Installation

Add this line to your application's Gemfile:

gem 'carrierwave-cascade'

Usage

Configure carrierwave to use Cascade as its storage engine. Then set primary and secondary storages to be used. Supply other configuration as needed for the storages.

CarrierWave.configure do |config|
  config.storage    = :cascade
  config.primary_storage   = :file
  config.secondary_storage = :fog

  config.fog_credentials = {
    :provider               => 'AWS'
  }
end

By default, cascade will prevent files from being deleted out of the secondary storage. If you wish secondary storage file to be deleted, specify this in the configs.

CarrierWave.configure do |config|
  config.allow_secondary_file_deletion = true
end

Contributing

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

carrierwave-cascade's Issues

Cascading 2 of the same provider type

Is it possible to cascade 2 of the same provider types, such as S3, where each uses a different configuration? For instance, the primary storage works with bucket A while the secondary works with bucket B. Bucket A should be the read-write bucket, while bucket B is read-only.

From the look of things this isn't currently possible because no facility is provided to enable per storage configuration. Everything must be handled within the top level configuration.