Synchronises Assets between Rails and S3.

Asset Sync is built to run with the new Rails Asset Pipeline feature of Rails 3.1. After you run bundle exec rake assets:precompile your assets will be synchronised to your S3 bucket, optionally deleting unused files and only uploading the files it needs to.

This was initially built and is intended to work on Heroku

Add the gem to your Gemfile

gem "asset_sync"

Generate the rake task and config files

rails g asset_sync:install

Configure config/environments/production.rb to use Amazon S3 as the asset host and ensure precompiling is enabled.

# config/environments/production.rb
config.action_controller.asset_host = Proc.new do |source, request|
  request.ssl? ? 'https://my_bucket.s3.amazonaws.com' : 'http://my_bucket.s3.amazonaws.com'
end

The recommend way to configure your asset_sync.yml is by adding an environment variable. That way your access keys are not checked into version control.

defaults: &defaults
  access_key_id: "<%= ENV['AWS_ACCESS_KEY'] %>"
  secret_access_key: "<%= ENV['AWS_ACCESS_SECRET'] %>"
  # You may need to specify what region your S3 bucket is in
  # region: "eu-west-1"

development:
  <<: *defaults
  bucket: "backoffice_development"
  existing_remote_files: keep # Existing pre-compiled assets on S3 will be kept

test:
  <<: *defaults
  bucket: "backoffice_test"
  existing_remote_files: keep

production:
  <<: *defaults
  bucket: "backoffice_production"
  existing_remote_files: delete # Existing pre-compiled assets on S3 will be deleted

Add your Amazon S3 configuration details to heroku

heroku config:add AWS_ACCESS_KEY=xxxx
heroku config:add AWS_ACCESS_KEY=xxxx

Or add to a traditional unix system

export AWS_ACCESS_KEY=xxxx
export AWS_ACCESS_SECRET=xxxx

If you are using anything other than the US buckets with S3 then you'll want to set the region. For example with an EU bucket you could set the following

production:
  access_key_id: 'MY_ACCESS_KEY'
  secret_access_key: 'MY_ACCESS_SECRET'
  region: 'eu-west-1'

• access_key_id: your Amazon S3 access key
• secret_access_key: your Amazon S3 access secret
• region: the region your S3 bucket is in e.g. eu-west-1
• existing_remote_files: what to do with previously precompiled files, options are keep or delete

A rake task is installed with the generator to enhance the rails precompile task by automatically running after it:

# lib/tasks/asset_sync.rake
Rake::Task["assets:precompile"].enhance do
  AssetSync::Assets.sync
end

1. Write some specs
2. Add some before and after filters for deleting and uploading
3. Provide more configuration options

Have borrowed ideas from:

• https://github.com/moocode/asset_id
• https://gist.github.com/1053855

MIT License. Copyright 2011 Rumble Labs Ltd. rumblelabs.com