Heroku Application Error App don't go Live - ruby-on-rails

Question

well i'm trying to deploy my application using Heroku and I'm getting some errors that my internet digging was not enough to solve. The deploy goes fine, showing it was successful:
remote: Verifying deploy... done.
To https://git.heroku.com/MYAPPHERE.git
7715c7c..c85251d master -> master
but when I go to the domain it shows this message:
"Application Error, An error occurred in the application and your page could not be served. If you are the application owner, check your logs for details."
my logs show this:
018-05-18T19:14:24.000000+00:00 app[api]: Build succeeded
2018-05-18T19:14:28.864974+00:00 heroku[web.1]: Starting process with command `bundle exec puma -C config/puma.rb`
2018-05-18T19:14:31.064709+00:00 app[web.1]: [4] Puma starting in cluster mode...
2018-05-18T19:14:31.064729+00:00 app[web.1]: [4] * Version 3.11.4 (ruby 2.3.1-p112), codename: Love Song
2018-05-18T19:14:31.064730+00:00 app[web.1]: [4] * Min threads: 5, max threads: 5
2018-05-18T19:14:31.064732+00:00 app[web.1]: [4] * Environment: production
2018-05-18T19:14:31.064752+00:00 app[web.1]: [4] * Process workers: 2
2018-05-18T19:14:31.064776+00:00 app[web.1]: [4] * Preloading application
2018-05-18T19:14:33.736893+00:00 app[web.1]: [4] * Listening on tcp://0.0.0.0:36902
2018-05-18T19:14:33.737145+00:00 app[web.1]: [4] * Listening on tcp://0.0.0.0:36902
2018-05-18T19:14:33.737416+00:00 app[web.1]: bundler: failed to load command: puma (/app/vendor/bundle/ruby/2.3.0/bin/puma)
2018-05-18T19:14:33.737462+00:00 app[web.1]: Errno::EADDRINUSE: Address already in use - bind(2) for "0.0.0.0" port 36902
2018-05-18T19:14:33.737465+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/binder.rb:270:in `initialize'
2018-05-18T19:14:33.737466+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/binder.rb:270:in `new'
2018-05-18T19:14:33.737468+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/binder.rb:270:in `add_tcp_listener'
2018-05-18T19:14:33.737469+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/binder.rb:105:in `block in parse'
2018-05-18T19:14:33.737471+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/binder.rb:88:in `each'
2018-05-18T19:14:33.737472+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/binder.rb:88:in `parse'
2018-05-18T19:14:33.737474+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/runner.rb:144:in `load_and_bind'
2018-05-18T19:14:33.737475+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/cluster.rb:397:in `run'
2018-05-18T19:14:33.737477+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/launcher.rb:184:in `run'
2018-05-18T19:14:33.737478+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/lib/puma/cli.rb:78:in `run'
2018-05-18T19:14:33.737480+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/gems/puma-3.11.4/bin/puma:10:in `<top (required)>'
2018-05-18T19:14:33.737482+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/bin/puma:23:in `load'
2018-05-18T19:14:33.737483+00:00 app[web.1]: /app/vendor/bundle/ruby/2.3.0/bin/puma:23:in `<top (required)>'
2018-05-18T19:14:33.833127+00:00 heroku[web.1]: State changed from starting to up
2018-05-18T19:14:33.953708+00:00 heroku[web.1]: State changed from up to crashed
2018-05-18T19:14:33.931364+00:00 heroku[web.1]: Process exited with status 1
2018-05-18T19:14:35.621801+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=MYAPPNAME request_id=74c67c85-dce7-4da8-9770-f41513d8cf31 fwd="179.178.13.25" dyno= connect= service= status=503 bytes= protocol=https
On my gemfile:
# Use Puma as the app server
gem 'puma', '~> 3.7'
on config/puma:
plugin :tmp_restart
workers Integer(ENV['WEB_CONCURRENCY'] || 2)
threads_count = Integer(ENV['RAILS_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
I see that an error occurred with the Address, but I don't use this address for anything at all. I tried running lsof -wni tcp:36902 and it shows nothing.
Hope I provided enough information.

Answer 1

Seems like puma is trying to bind listeners twice:
2018-05-18T19:14:33.736893+00:00 app[web.1]: [4] * Listening on tcp://0.0.0.0:36902
2018-05-18T19:14:33.737145+00:00 app[web.1]: [4] * Listening on tcp://0.0.0.0:36902
You may want to try moving your preload_app! below your port & environment configuration. (by calling port, it may be calling two bind functions similar to here)
I'm running Heroku w/ puma 3.11.4 currently, and my config/puma.rb looks like:
threads_count = ENV.fetch('RAILS_MAX_THREADS', 5)
threads threads_count, threads_count
environment ENV.fetch('RAILS_ENV', 'development')
port ENV.fetch('PORT', 3000)
workers ENV.fetch('WEB_CONCURRENCY', 2)
preload_app!
before_fork do
ActiveRecord::Base.connection_pool.disconnect! if defined?(ActiveRecord)
end
on_worker_boot do
ActiveRecord::Base.establish_connection if defined?(ActiveRecord)
end
# Allow puma to be restarted by `rails restart` command.
plugin :tmp_restart
It might also be helpful to see your Procfile. Just want to confirm it looks something like:
A simple Procfile might be:
web: bundle exec puma -C config/puma.rb