Rails giving undefined method `workers' for main:Object (NoMethodError)

Question

I am trying to setup puma on heroku for a rails app. I'm following Heroku's guide on how to do it, but the config file they give doesn't seem to work, and I can't figure out why. When I don't use any config file, it runs fine, but I want to be able to specify the number of workers and threads it uses.

When I try to run the server, I get the following error:

C:/Users/Ephraim/Documents/lis/rails_app/config/initializers/puma.rb:1:in `<top (required)>': undefined method `workers' for main:Object (NoMethodError)
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `load'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `block in load'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `load'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/engine.rb:652:in `block in load_config_initializer'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/notifications.rb:166:in `instrument'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/engine.rb:651:in `load_config_initializer'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/engine.rb:616:in `block (2 levels) in <class:Engine>'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/engine.rb:615:in `each'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/engine.rb:615:in `block in <class:Engine>'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/initializable.rb:30:in `instance_exec'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/initializable.rb:30:in `run'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/initializable.rb:55:in `block in run_initializers'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:226:in `block in tsort_each'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:418:in `block (2 levels) in each_strongly_connected_component_from'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:427:in `each_strongly_connected_component_from'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:417:in `block in each_strongly_connected_component_from'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/initializable.rb:44:in `each'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/initializable.rb:44:in `tsort_each_child'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:411:in `call'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:411:in `each_strongly_connected_component_from'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:347:in `block in each_strongly_connected_component'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:345:in `each'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:345:in `call'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:345:in `each_strongly_connected_component'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:224:in `tsort_each'
from C:/Ruby21-x64/lib/ruby/2.1.0/tsort.rb:205:in `tsort_each'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/initializable.rb:54:in `run_initializers'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/application.rb:352:in `initialize!'
from C:/Users/Ephraim/Documents/lis/rails_app/config/environment.rb:5:in `<top (required)>'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `block in require'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:240:in `load_dependency'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:274:in `require'
from C:/Users/Ephraim/Documents/lis/rails_app/config.ru:3:in `block in <main>'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in `instance_eval'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in `initialize'
from C:/Users/Ephraim/Documents/lis/rails_app/config.ru:in `new'
from C:/Users/Ephraim/Documents/lis/rails_app/config.ru:in `<main>'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in `eval'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in `new_from_string'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:40:in `parse_file'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/server.rb:299:in `build_app_and_options_from_config'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/server.rb:208:in `app'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands/server.rb:61:in `app'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/server.rb:336:in `wrapped_app'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands/server.rb:139:in `log_to_stdout'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands/server.rb:78:in `start'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:80:in `block in server'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `tap'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `server'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top (required)>'
from C:/Users/Ephraim/Documents/lis/rails_app/bin/rails:8:in `require'
from C:/Users/Ephraim/Documents/lis/rails_app/bin/rails:8:in `<top (required)>'
from -e:1:in `load'
from -e:1:in `<main>'

Here is the puma.rb initializer I'm using:

workers Integer(ENV['WEB_CONCURRENCY'] || 2)
threads_count = Integer(ENV['MAX_THREADS'] || 5)
threads threads_count, threads_count

preload_app!

rackup      DefaultRackup
port        ENV['PORT']     || 3000
environment ENV['RACK_ENV'] || 'development'

on_worker_boot do
  # Worker specific setup for Rails 4.1+
  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
  ActiveRecord::Base.establish_connection
end

What would cause this to happen? And how can I fix it?

Answer 1

Referencing an answer from here: puma initializer does not work with rails 4.2

Put the puma.rb file in config/ not config/initializers/

Answer 2

you need to use foreman https://github.com/ddollar/foreman to run the Procfile. That is how heroku will spool up the app. once installed foreman start should do the trick. this just fooled me for a bit and I ran across your question.