puma: Restarting via `SIGUSR2` broken in 3.9.0 works in 3.8.2

Steps to reproduce

Updated application from puma 3.8.2 to 3.9.0
start puma server bundle exec puma -p 3000
send USR2 kill -SIGUSR2 <pid>

Expected behavior

Puma server should be restarting and does so correctly in 3.8.2

Actual behavior

With version 3.9.0 the outcome is

* Listening on tcp://0.0.0.0:3000
Use Ctrl-C to stop
* Restarting...
/usr/local/lib/ruby/2.3.0/rubygems/dependency.rb:319:in `to_specs': Could not find 'puma' (>= 0.a) among 19 total gem(s) (Gem::LoadError)

System configuration

Ruby version: ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-linux] Rails version: rails-5.0.3

About this issue

Original URL
State: closed
Created 7 years ago
Reactions: 1
Comments: 42 (31 by maintainers)

Commits related to this issue

Downgrade to Puma 3.8.1 The current version of Puma seems to have problems with restarting, downgrade to 3.8.1 should fix this. See also: https://github.com/seuros/capistrano-puma/issues/237 and http... — committed to OpenlyOne/openly-rails by FinnWoelm 7 years ago

Most upvoted comments

none of the options and workarounds worked for me on 3.9.1, had to rollback to 3.8.2 which works fine

glebtv on Jul 4, 2017

Closed by #1385

nateberkopec on Aug 16, 2017

I can confirm that switching back to puma 3.8.1 solved the issue.

vizcay on Jul 27, 2017

@grosser https://github.com/stereobooster/ruby-server-experiment/tree/master/puma-symlink-grosser

UPD: @grosser why do you prefer USR2 over USR1 restart?

PS simplified patch
require 'bundler/setup'
on_restart do
  ENV.replace(Bundler.clean_env)
end

@stereobooster the error is different:

As mentioned here, fIx is for:

uninitialized constant #<Class:#<Puma::DSL:0x0055883f37e188>>::Bundler (NameError)

but the error I (and probably others) am getting is:

`find_spec_for_exe': can't find gem puma (>= 0.a) (Gem::GemNotFoundException)

Info:

$ ~/.rvm/bin/rvm ruby-2.4.1 do ruby -v
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]

$ ~/.rvm/bin/rvm ruby-2.4.1 do gem -v
2.6.11

$ ~/.rvm/bin/rvm ruby-2.4.1 do bundle -v
Bundler version 1.15.1

$ ~/.rvm/bin/rvm ruby-2.4.1 do bundle exec rails -v
Rails 5.1.2

$ uname -a                                                                                                                                                                                            
Linux ip-172-31-30-115 4.4.0-83-generic #106-Ubuntu SMP Mon Jun 26 17:54:43 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Okay, using puma-3.8.1 is the clean and simple workaround. Thanks @dguettler and @tagliala.

vedant1811 on Jul 11, 2017

Same here. Workaround didn’t help, downgrading to 3.8.2 works

ruby -v
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]

gem -v
2.6.12

bundle -v
Bundler version 1.15.1

bundle exec rails -v
Rails 5.1.2

uname -a
Linux <NAME> 3.10.0-514.el7.x86_64 #1 SMP Tue Nov 22 16:42:41 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

tagliala on Jul 11, 2017

Experienced the same problem - simply updating to the latest version of bundler (1.15.1) fixed it for me.

jaybloke on Jun 23, 2017

add gemspec to Gemfile and remove the dependencies like https://github.com/puma/puma/pull/1313 does then

gem uninstall puma -a
bundle exec puma test/rackup/hello.ru
ps -ef | grep puma
kill -SIGUSR2 <puma-pid>

-> kaboom

grosser on Jun 2, 2017

hmm I think this is because it restarts with an environment that does not have bundler so should tweak the restart command to include bundle exec … I though I tried that … for now might be able to fix it by setting --restart-command manually will take a look shortly

grosser on Jun 1, 2017