puma: Error reached top of thread-pool: EOFError (EOFError)

Frequently for us in dev, puma hits an error in its thread pool, grinding the web server to a halt. This happens on page refreshes on our Rails app. I’m making an issue out of desperation, but I have not a lot to go on.

It appears this block catches some kind of internal error, but no backtrace is attached for us:

https://github.com/puma/puma/blob/master/lib/puma/thread_pool.rb#L121

          begin
            block.call(work, *extra)
          rescue Exception => e
            STDERR.puts "Error reached top of thread-pool: #{e.message} (#{e.class})"
          end

After a few of those in the logs, we also sometimes see:

16:51:09 web.1 | Error in reactor loop escaped: undefined method join’ for nil:NilClass (NoMethodError)`

Does anyone have a hunch about where this might be coming from?

System configuration

Ruby version: 2.5.0 Rails version: 5.1.4 Puma version: 3.11.0

About this issue

Original URL
State: closed
Created 6 years ago
Reactions: 5
Comments: 18 (2 by maintainers)

Commits related to this issue

Regress puma to 3.10 Temporary work around for “no implicit conversion of nil into String” See https://github.com/puma/puma/issues/1483 and https://github.com/puma/puma/issues/1502 — committed to lgebhardt/publishers by lgebhardt 6 years ago

Most upvoted comments

I’m also seeing the same error reported by tuwukee on 3.11.4

2018-06-01 12:55:57 +0000: Read error: #<EOFError: EOFError>
/usr/local/bundle/gems/puma-3.11.3/lib/puma/client.rb:292:in `try_to_finish'
/usr/local/bundle/gems/puma-3.11.3/lib/puma/client.rb:106:in `reset'
/usr/local/bundle/gems/puma-3.11.3/lib/puma/server.rb:450:in `process_client'
/usr/local/bundle/gems/puma-3.11.3/lib/puma/server.rb:302:in `block in run'

Ruby 2.5.0 Rails 5.2.0

bruno-campos on Jun 4, 2018

So I updated to 3.11.2 to fix this issue. While the issue log errors mentioned here no longer show up, I am now getting the following errors in the puma.log file with most HTTP requests (over SSL of course):

=== puma startup: 2018-02-01 08:00:55 -0500 === === puma startup: 2018-02-01 08:00:55 -0500 === Error reached top of thread-pool: EOFError (EOFError) Error reached top of thread-pool: EOFError (EOFError) Error reached top of thread-pool: EOFError (EOFError) Error reached top of thread-pool: EOFError (EOFError) Error reached top of thread-pool: EOFError (EOFError) Error reached top of thread-pool: EOFError (EOFError)Error reached top of thread-pool: EOFError (EOFError) Error reached top of thread-pool: EOFError (EOFError)

anyone have any idea what could be going on? I haven’t noticed any bad user experience yet (e.g. puma crash or http request hang)

Thanks, Rafael

rrevi on Feb 1, 2018

Looks like the issue with EOFError is already fixed.

The code version where the EOFError error was reported to happen - source code. Currently any IO error is rescued and swallowed here source code.

This change was introduce in https://github.com/puma/puma/pull/1728 and released in v4.0.0 (Changelog)

andrykonchin on Mar 9, 2020

Reopening until @tuwukee’s comment is addressed.

nateberkopec on Mar 20, 2018