How do I run a rake task from Capistrano?

Question

I already have a deploy.rb that can deploy my app on my production server.

My app contains a custom rake task (a .rake file in the lib/tasks directory).

I'd like to create a cap task that will remotely run that rake task.

Answer 1

If you want to be able to pass multiple arguments try this (based on marinosbern's answer):

task :invoke, [:command] => 'deploy:set_rails_env' do |task, args|
  on primary(:app) do
    within current_path do
      with :rails_env => fetch(:rails_env) do
        execute :rake, "#{args.command}[#{args.extras.join(",")}]"
      end
    end
  end
end

Then you can run a task like so: cap production invoke["task","arg1","arg2"]

Answer 2

A little bit more explicit, in your \config\deploy.rb, add outside any task or namespace:

namespace :rake do  
  desc "Run a task on a remote server."  
  # run like: cap staging rake:invoke task=a_certain_task  
  task :invoke do  
    run("cd #{deploy_to}/current; /usr/bin/env rake #{ENV['task']} RAILS_ENV=#{rails_env}")  
  end  
end

Then, from /rails_root/, you can run:

cap staging rake:invoke task=rebuild_table_abc

Answer 3

Most of it is from above answer with a minor enhancement to run any rake task from capistrano

Run any rake task from capistrano

$ cap rake -s rake_task=$rake_task

# Capfile     
task :rake do
  rake = fetch(:rake, 'rake')
  rails_env = fetch(:rails_env, 'production')

  run "cd '#{current_path}' && #{rake} #{rake_task} RAILS_ENV=#{rails_env}"
end

Answer 4

There's an interesting gem cape that makes your rake tasks available as Capistrano tasks, so you can run them remotely. cape is well documented, but here's a short overview on how to set i up.

After installing the gem, just add this to your config/deploy.rb file.

# config/deploy.rb
require 'cape'
Cape do
  # Create Capistrano recipes for all Rake tasks.
  mirror_rake_tasks
end

Now, you can run all you rake tasks locally or remotely through cap.

As an added bonus, cape lets you set how you want to run your rake task locally and remotely (no more bundle exec rake), just add this to your config/deploy.rb file:

# Configure Cape to execute Rake via Bundler, both locally and remotely.
Cape.local_rake_executable  = '/usr/bin/env bundle exec rake'
Cape.remote_rake_executable = '/usr/bin/env bundle exec rake'

Answer 5

This also works:

run("cd #{release_path}/current && /usr/bin/rake <rake_task_name>", :env => {'RAILS_ENV' => rails_env})

More info: Capistrano Run

Answer 6

So I have been working on this. it seams to work well. However you need a formater to really take advantage of the code.

If you don't want to use a formatter just set the log level to to debug mode. These semas to h

SSHKit.config.output_verbosity = Logger::DEBUG

Cap Stuff

namespace :invoke do
  desc 'Run a bash task on a remote server. cap environment invoke:bash[\'ls -la\'] '
  task :bash, :execute do |_task, args|
    on roles(:app), in: :sequence do
      SSHKit.config.format = :supersimple
      execute args[:execute]
    end
  end

  desc 'Run a rake task on a remote server. cap environment invoke:rake[\'db:migrate\'] '
  task :rake, :task do |_task, args|
    on primary :app do
      within current_path do
        with rails_env: fetch(:rails_env) do
          SSHKit.config.format = :supersimple
          rake args[:task]
        end
      end
    end
  end
end

This is the formatter I built to work with the code above. It is based off the :textsimple built into the sshkit but it is not a bad way to invoke custom tasks. Oh this many not works with the newest version of sshkit gem. I know it works with 1.7.1. I say this because the master branch has changed the SSHKit::Command methods that are available.

module SSHKit
  module Formatter
    class SuperSimple < SSHKit::Formatter::Abstract
      def write(obj)
        case obj
        when SSHKit::Command    then write_command(obj)
        when SSHKit::LogMessage then write_log_message(obj)
        end
      end
      alias :<< :write

      private

      def write_command(command)
        unless command.started? && SSHKit.config.output_verbosity == Logger::DEBUG
          original_output << "Running #{String(command)} #{command.host.user ? "as #{command.host.user}@" : "on "}#{command.host}\n"
          if SSHKit.config.output_verbosity == Logger::DEBUG
            original_output << "Command: #{command.to_command}" + "\n"
          end
        end

        unless command.stdout.empty?
          command.stdout.lines.each do |line|
            original_output << line
            original_output << "\n" unless line[-1] == "\n"
          end
        end

        unless command.stderr.empty?
          command.stderr.lines.each do |line|
            original_output << line
            original_output << "\n" unless line[-1] == "\n"
          end
        end

      end

      def write_log_message(log_message)
        original_output << log_message.to_s + "\n"
      end
    end
  end
end