Capistrano 3 upgrade problems - ruby-on-rails

Question

I've been trying to upgrade from Capistrano 2 to Capistrano 3, but have been working through all the errors. I'm stuck on one that I don't know how to solve now. I'm using Unicorn and Nginx.
Error trace:
cap production deploy:cold --trace
** Invoke production (first_time)
** Execute production
** Invoke load:defaults (first_time)
** Execute load:defaults
cap aborted!
Task Argument Error
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task_manager.rb:96:in `resolve_args_with_dependencies'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task_manager.rb:62:in `resolve_args'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task_manager.rb:24:in `define_task'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:360:in `define_task'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/dsl_definition.rb:32:in `task'
config/deploy.rb:31:in `block (2 levels) in <top (required)>'
config/deploy.rb:29:in `each'
config/deploy.rb:29:in `block in <top (required)>'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task_manager.rb:196:in `in_namespace'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/dsl_definition.rb:104:in `namespace'
config/deploy.rb:28:in `<top (required)>'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/capistrano-3.0.1/lib/capistrano/setup.rb:12:in `load'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/capistrano-3.0.1/lib/capistrano/setup.rb:12:in `block (2 levels) in <top (required)>'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:236:in `call'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:236:in `block in execute'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:231:in `each'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:231:in `execute'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:175:in `block in invoke_with_call_chain'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:168:in `invoke_with_call_chain'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/task.rb:161:in `invoke'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:149:in `invoke_task'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:106:in `each'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:106:in `block in top_level'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:115:in `run_with_threads'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:100:in `top_level'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:78:in `block in run'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:165:in `standard_exception_handling'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rake-10.1.1/lib/rake/application.rb:75:in `run'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/capistrano-3.0.1/lib/capistrano/application.rb:12:in `run'
/Users/devanb/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/capistrano-3.0.1/bin/cap:3:in `<top (required)>'
/Users/devanb/.rbenv/versions/2.0.0-p247/bin/cap:23:in `load'
/Users/devanb/.rbenv/versions/2.0.0-p247/bin/cap:23:in `<main>'
Tasks: TOP => production
Deploy file:
set :application, 'liveinbham'
set :user, 'deployer'
set :deploy_to, "/home/#{fetch(:user)}/apps/#{fetch(:application)}"
set :scm, "git"
set :repo_url, 'git#github.com:DevanB/LIveInBham.git'
set :use_sudo, false
set :scm_verbose, true
set :git_shallow_clone, 1
set :git_enable_submodules, 1
set :ssh_options, { :forward_agent => true }
set :stage, :production
set :rails_env, "production"
set :branch, "master"
set :pty, true
set :linked_files, %w{config/database.yml}
set :linked_dirs, %w{bin log tmp/pids tmp/cache tmp/sockets vendor/bundle public/system public/uploads}
set :keep_releases, 5
namespace :deploy do
%w{start stop restart}.each do |command|
desc "#{command} unicorn server"
task command, roles: :app, except: {no_release: true} do
run "/etc/init.d/unicorn_#{fetch(:application)} #{command}"
end
end
task :setup_config, roles: :app do
sudo "ln -nfs #{current_path}/config/nginx.conf /etc/nginx/sites-enabled/#{fetch(:application)}"
sudo "ln -nfs #{current_path}/config/unicorn_init.sh /etc/init.d/unicorn_#{fetch(:application)}"
end
after "deploy:setup", "deploy:setup_config"
after :finishing, 'deploy:cleanup'
end
desc "tail log files"
task :tail, :roles => :app do
run "tail -f /home/#{fetch(:user)}/apps/#{fetch(:application)}/current/log/production.log" do |channel, stream, data|
puts "#{channel[:host]}: #{data}"
break if stream == :err
end
end
desc "Open the rails console on one of the remote servers"
task :console, :roles => :app do
hostname = find_servers_for_task(current_task).first
exec "ssh -l #{fetch(:user)} #{hostname} -t 'source ~/.profile && #{current_path}/script/rails c #{fetch(:rails_env)}'"
end

Answer 1

Could be a few things but deploy:cold is depreciated in Capistrano 3, I've just tried it and I just get "don't know how to build task" which is what I'd expect. Potentially running deploy:setup_config and then just a straight up deploy may work.
There's a few other things which will need tweaking like you can no longer use that approach for streaming log files, it's just a simple execute instead. E.g.:
namespace :logs do
desc "tail rails logs"
task :tail_rails do
on roles(:app) do
execute "tail -f #{shared_path}/log/#{fetch(:rails_env)}.log"
end
end
end
In general the task definition format also needs updating, e.g:
task :setup_config, roles: :app do
# some stuff
end
would become
task :setup_config do
on roles(:app) do
#some stuff
end
end
It looks like your Cap 2 configuration is based quite heavily on the Railscast about it. Mine also was and I recently went through the process of migrating all the apps using it to a new Cap 3 one. I've documented the approach I ended up with here including the code.

Answer 2

The stack trace makes it pretty clear. The error comes from line 31 of your file, where you try to define a task using the old Capistrano 2 syntax. The new Capistrano 3 uses Rake, so you must use Rake syntax to define tasks, with the aid of some Capistrano methods. Rake does not recognize "roles" and "except". TalkingQuickly gave a good-looking example of the new way to define tasks.