Rake task to synchronize assets to S3 (via asset_sync) and deploy to heroku, optionally migrating the database if that needs doing.

deploy.rake

# This is inspired by http://ckdake.com/comment/reply/362

desc "Deploy ALL the targets"
task :deploy => ["deploy:assets", "deploy:heroku"]

namespace :deploy do
  desc "Synchronize assets to S3"
  task assets: [:environment,
                :load_config,
                "assets:precompile",
                "assets:clean"]

  desc "Push code to heroku and migrate the database, if needed"
  task :heroku do
    current_version = `git ls-remote heroku master | awk '{ print $1 }'`.chomp
    schema_changed = `git log --pretty=%H #{current_version}.. -- db/schema.rb`.strip.present?
    system "git push heroku"
    exec "heroku run rake db:migrate" if schema_changed
  end

  task :load_config do
    YAML.load_file("config/asset_sync.yml").fetch("defaults").each do |key, val|
      ENV[key.upcase] = val.to_s
    end
  end
end