on Ruby on Rails - Heroku deployment, I got a error of heroku[route]: at=error code=H10 desc="App crashed" method After some debugging the log texts, main part of the log file I got:
2022-01-08T11:12:12.754916+00:00 heroku[web.1]: Starting process with command `bin/rails server -p ${PORT:-5000} -e production`
2022-01-08T11:12:16.534794+00:00 app[web.1]: => Booting Puma
2022-01-08T11:12:16.534809+00:00 app[web.1]: => Rails 6.1.4.4 application starting in production
2022-01-08T11:12:16.534810+00:00 app[web.1]: => Run `bin/rails server --help` for more startup options
2022-01-08T11:12:17.742438+00:00 app[web.1]: Exiting
2022-01-08T11:12:17.745593+00:00 app[web.1]: /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:34:in `require': cannot load such file -- net/pop (LoadError)
2022-01-08T11:12:17.745616+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:35:in `require'
2022-01-08T11:12:17.745630+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail/network/retriever_methods/pop3.rb:36:in `<class:POP3>'
2022-01-08T11:12:17.745642+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail/network/retriever_methods/pop3.rb:35:in `<module:Mail>'
2022-01-08T11:12:17.745655+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail/network/retriever_methods/pop3.rb:4:in `<main>'
2022-01-08T11:12:17.745668+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
2022-01-08T11:12:17.745681+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
2022-01-08T11:12:17.745694+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/loaded_features_index.rb:100:in `register'
2022-01-08T11:12:17.745708+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
2022-01-08T11:12:17.745720+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
2022-01-08T11:12:17.745733+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:35:in `require'
2022-01-08T11:12:17.745745+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail.rb:54:in `block in eager_autoload!'
2022-01-08T11:12:17.745761+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail.rb:54:in `each'
2022-01-08T11:12:17.745774+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail.rb:54:in `eager_autoload!'
2022-01-08T11:12:17.745786+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/actionmailer-6.1.4.4/lib/action_mailer.rb:61:in `eager_load!'
2022-01-08T11:12:17.745799+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/application/finisher.rb:134:in `each'
2022-01-08T11:12:17.745811+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/application/finisher.rb:134:in `block in <module:Finisher>'
2022-01-08T11:12:17.745824+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/initializable.rb:32:in `instance_exec'
2022-01-08T11:12:17.745838+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/initializable.rb:32:in `run'
2022-01-08T11:12:17.745850+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/initializable.rb:61:in `block in run_initializers'
2022-01-08T11:12:17.745863+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:228:in `block in tsort_each'
2022-01-08T11:12:17.745875+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component'
2022-01-08T11:12:17.745888+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:431:in `each_strongly_connected_component_from'
2022-01-08T11:12:17.745900+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:349:in `block in each_strongly_connected_component'
2022-01-08T11:12:17.745913+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:347:in `each'
2022-01-08T11:12:17.745926+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:347:in `call'
2022-01-08T11:12:17.745938+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:347:in `each_strongly_connected_component'
2022-01-08T11:12:17.745950+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:226:in `tsort_each'
2022-01-08T11:12:17.745963+00:00 app[web.1]: from /app/vendor/ruby-3.1.0/lib/ruby/3.1.0/tsort.rb:205:in `tsort_each'
2022-01-08T11:12:17.745975+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/initializable.rb:60:in `run_initializers'
2022-01-08T11:12:17.745988+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/application.rb:391:in `initialize!'
2022-01-08T11:12:17.746002+00:00 app[web.1]: from /app/config/environment.rb:5:in `<main>'
2022-01-08T11:12:17.746015+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
2022-01-08T11:12:17.746027+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
2022-01-08T11:12:17.746040+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/loaded_features_index.rb:100:in `register'
2022-01-08T11:12:17.746053+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
2022-01-08T11:12:17.746066+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
2022-01-08T11:12:17.746079+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:35:in `require'
2022-01-08T11:12:17.746092+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/activesupport-6.1.4.4/lib/active_support/dependencies.rb:332:in `block in require'
2022-01-08T11:12:17.746104+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/activesupport-6.1.4.4/lib/active_support/dependencies.rb:299:in `load_dependency'
2022-01-08T11:12:17.746117+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/activesupport-6.1.4.4/lib/active_support/dependencies.rb:332:in `require'
2022-01-08T11:12:17.746130+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:54:in `require_relative'
2022-01-08T11:12:17.746143+00:00 app[web.1]: from config.ru:3:in `block in <main>'
2022-01-08T11:12:17.746156+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/builder.rb:116:in `eval'
2022-01-08T11:12:17.746169+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/builder.rb:116:in `new_from_string'
2022-01-08T11:12:17.746181+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/builder.rb:105:in `load_file'
2022-01-08T11:12:17.746194+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/builder.rb:66:in `parse_file'
2022-01-08T11:12:17.746206+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/server.rb:349:in `build_app_and_options_from_config'
2022-01-08T11:12:17.746219+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/server.rb:249:in `app'
2022-01-08T11:12:17.746232+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/server.rb:422:in `wrapped_app'
2022-01-08T11:12:17.746245+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/server.rb:312:in `block in start'
2022-01-08T11:12:17.746258+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/server.rb:379:in `handle_profiling'
2022-01-08T11:12:17.746270+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/rack-2.2.3/lib/rack/server.rb:311:in `start'
2022-01-08T11:12:17.746283+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/commands/server/server_command.rb:39:in `start'
2022-01-08T11:12:17.746297+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/commands/server/server_command.rb:144:in `block in perform'
2022-01-08T11:12:17.746309+00:00 app[web.1]: from <internal:kernel>:90:in `tap'
2022-01-08T11:12:17.746322+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/commands/server/server_command.rb:135:in `perform'
2022-01-08T11:12:17.746335+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/thor-1.2.1/lib/thor/command.rb:27:in `run'
2022-01-08T11:12:17.746348+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/thor-1.2.1/lib/thor/invocation.rb:127:in `invoke_command'
2022-01-08T11:12:17.746361+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/thor-1.2.1/lib/thor.rb:392:in `dispatch'
2022-01-08T11:12:17.746373+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/command/base.rb:69:in `perform'
2022-01-08T11:12:17.746386+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/command.rb:48:in `invoke'
2022-01-08T11:12:17.746399+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/railties-6.1.4.4/lib/rails/commands.rb:18:in `<main>'
2022-01-08T11:12:17.746412+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `require'
2022-01-08T11:12:17.746424+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:23:in `block in require_with_bootsnap_lfi'
2022-01-08T11:12:17.746437+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/loaded_features_index.rb:100:in `register'
2022-01-08T11:12:17.746451+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require_with_bootsnap_lfi'
2022-01-08T11:12:17.746463+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:31:in `require'
2022-01-08T11:12:17.746476+00:00 app[web.1]: from bin/rails:5:in `<main>'
2022-01-08T11:12:17.961296+00:00 heroku[web.1]: Process exited with status 1
2022-01-08T11:12:18.044550+00:00 heroku[web.1]: State changed from starting to crashed
Though this was the main topic of the full log text on production environment, but in local development environment, there was no issues found while starting the Rails server! Everything was working fine on development environment.
Besides, the URL was showing the following texts:
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. You can do this from the Heroku CLI with the command heroku logs --tail
And the console is showing this: Failed to load resource: the server responded with a status of 503 (Service Unavailable)
Solution
Ok, after a few deployments of fixing the errors found from the log file, I got that, in our Gemfile, we need to add some gem (around 3 gems) which are needed for some dependencies. Those gems are:
after adding those to our gem file, run
Then deploy the code on heroku and this will make a proper deployment.