Custom Rails Tasks

Many of these tasks probably require Capistrano::Rails.

Run arbitrary rake tasks from environment variables

From Capistrano/Rails PR #209

namespace :deploy do
  desc 'Runs any rake task, cap deploy:rake task=db:rollback'
  task rake: [:set_rails_env] do
    on release_roles([:db]) do
      within release_path do
        with rails_env: fetch(:rails_env) do
          execute :rake, ENV['task']
        end
      end
    end
  end
end

Passes in the rake task to be run via an environment variable. Also a simple example of running a rake task on the server.

bundle exec cap production deploy:rake task=db:seed

Conditional migrations

Arising from Capistrano/Rails issue #199

A frequent issue on deploy are slow migrations which involve downtime. In this case, you often want to run the migrations conditionally, where the main deploy doesn’t run them, but you can do so manually at a better point. To do so, you could put the following in your Capfile:

require 'capistrano/rails/migrations' if ENV['RUN_MIGRATIONS']

Now the migrations do not run by default, but they will run with the following command:

RUN_MIGRATIONS=1 bundle exec cap production deploy:migrate