Ruby server does not start / No such file or directory - ruby-on-rails

Question

rails s -p 3001
=> Booting Puma
=> Rails 6.1.4.4 application starting in development
=> Run `bin/rails server --help` for more startup options
Puma starting in single mode...
* Puma version: 5.6.0 (ruby 2.6.9-p207) ("Birdie's Version")
* Min threads: 5
* Max threads: 5
* Environment: development
* PID: 86165
* Listening on http://127.0.0.1:3001
* Listening on http://[::1]:3001
Exiting
/Users/kadri/.rvm/gems/ruby-2.6.9/gems/puma-5.6.0/lib/puma/launcher.rb:248:in `write': No such file or directory # rb_sysopen - /var/run/puma/my_app.sock (Errno::ENOENT)
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/puma-5.6.0/lib/puma/launcher.rb:248:in `write_pid'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/puma-5.6.0/lib/puma/launcher.rb:112:in `write_state'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/puma-5.6.0/lib/puma/single.rb:48:in `run'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/puma-5.6.0/lib/puma/launcher.rb:182:in `run'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/puma-5.6.0/lib/rack/handler/puma.rb:72:in `run'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/rack-2.2.3/lib/rack/server.rb:327:in `start'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/railties-6.1.4.4/lib/rails/commands/server/server_command.rb:39:in `start'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/railties-6.1.4.4/lib/rails/commands/server/server_command.rb:144:in `block in perform'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/railties-6.1.4.4/lib/rails/commands/server/server_command.rb:135:in `tap'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/railties-6.1.4.4/lib/rails/commands/server/server_command.rb:135:in `perform'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/thor-1.2.1/lib/thor/command.rb:27:in `run'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/thor-1.2.1/lib/thor/invocation.rb:127:in `invoke_command'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/thor-1.2.1/lib/thor.rb:392:in `dispatch'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/railties-6.1.4.4/lib/rails/command/base.rb:69:in `perform'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/railties-6.1.4.4/lib/rails/command.rb:48:in `invoke'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/railties-6.1.4.4/lib/rails/commands.rb:18:in `<main>'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/bootsnap-1.10.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/bootsnap-1.10.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
from /Users/kadri/code/goconf-api/bin/rails:5:in `<top (required)>'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/spring-3.1.1/lib/spring/client/rails.rb:30:in `load'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/spring-3.1.1/lib/spring/client/rails.rb:30:in `call'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/spring-3.1.1/lib/spring/client/command.rb:7:in `call'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/spring-3.1.1/lib/spring/client.rb:30:in `run'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/spring-3.1.1/bin/spring:49:in `<top (required)>'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/spring-3.1.1/lib/spring/binstub.rb:11:in `load'
from /Users/kadri/.rvm/gems/ruby-2.6.9/gems/spring-3.1.1/lib/spring/binstub.rb:11:in `<top (required)>'
from /Users/kadri/code/goconf-api/bin/spring:10:in `require'
from /Users/kadri/code/goconf-api/bin/spring:10:in `block in <top (required)>'
from /Users/kadri/code/goconf-api/bin/spring:7:in `tap'
from /Users/kadri/code/goconf-api/bin/spring:7:in `<top (required)>'
from bin/rails:2:in `load'
from bin/rails:2:in `<main>'

Answer 1

It seems you have configured in your config/puma.rb file that the Puma application server should listed to a UNIX socket in /var/run/puma/my_app.sock
However, the directory /var/run/puma likely doesn't exist on your Mac (and if it doesn't you likely have no permissions to write there).
As such, you could edit your config/puma.rb file and remove the unix socket bind there or adapt it to a "normal" TCP bind. Possibly, you could also use environment variables instead depending on your actual code in that file.