Puma: Puma 3.7.0 listens only on port 3000 even when option is provided

[premist]

Steps to reproduce

1) Create a simple Rack app that uses Puma

2) Run bundle exec puma -p 8080

Expected behavior

It should listen on 8080 port I provided via command line option.

Actual behavior

Puma listens on tcp://0.0.0.0:3000

System configuration

Ruby version: 2.4.0p0
Rails version: 5.0.1
Puma version: 3.7.0

Log dump

When running with rails server command:

❯ bundle exec rails server -p 8080 -b 0.0.0.0
/Users/premist/.gem/ruby/2.4.0/gems/activesupport-5.0.1/lib/active_support/xml_mini.rb:51: warning: constant ::Fixnum is deprecated
/Users/premist/.gem/ruby/2.4.0/gems/activesupport-5.0.1/lib/active_support/xml_mini.rb:52: warning: constant ::Bignum is deprecated
=> Booting Puma
=> Rails 5.0.1 application starting in development on http://0.0.0.0:8080
=> Run `rails server -h` for more startup options
/Users/premist/.gem/ruby/2.4.0/gems/activesupport-5.0.1/lib/active_support/core_ext/numeric/conversions.rb:138: warning: constant ::Fixnum is deprecated
Puma starting in single mode...
* Version 3.7.0 (ruby 2.4.0-p0), codename: Snowy Sagebrush
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://0.0.0.0:3000
Use Ctrl-C to stop

When running with puma command:

❯ bundle exec puma -p 8888 -b 0.0.0.0
Puma starting in single mode...
* Version 3.7.0 (ruby 2.4.0-p0), codename: Snowy Sagebrush
* Min threads: 5, max threads: 5
* Environment: development
/Users/premist/.gem/ruby/2.4.0/gems/activesupport-5.0.1/lib/active_support/xml_mini.rb:51: warning: constant ::Fixnum is deprecated
/Users/premist/.gem/ruby/2.4.0/gems/activesupport-5.0.1/lib/active_support/xml_mini.rb:52: warning: constant ::Bignum is deprecated
/Users/premist/.gem/ruby/2.4.0/gems/activesupport-5.0.1/lib/active_support/core_ext/numeric/conversions.rb:138: warning: constant ::Fixnum is deprecated
* Listening on tcp://0.0.0.0:3000
Use Ctrl-C to stop

[nateberkopec]

Fixed on master, releasing in 3.7.1.

[MehmetKaplan]

For newbies (like me) simply edit your Gemfile.

By default(*) you should see something like:

# Use Puma as the app server
gem 'puma', '~> 3.0'

Replace the puma version as:

# Use Puma as the app server
# gem 'puma', '~> 3.0'
gem 'puma', '~> 3.7.1'

Then run following command under your rails application's root directory, for puma v3.7.1 to take effect:

bundle install

This indicates; 3.7.1 <= Puma version < 4.0 is OK for your application. Beautiful! :-)

(*) Of course that default value should change as rails evolve by time. So this post should be useful "nowadays".

[linediconsine]

I had the same problem with puma 3.7

Solved with above comment

in Gemfile
#gem 'puma', '~> 3.7' # commented gem 'puma', '~> 3.7.1'
and then on console:
$bundle install

Thanks