Gyoku is not threadsafe

[pschambacher]

Sometimes when using gyoku through Savon we get an exception like so:

NoMethodError: undefined method `upcase' for nil:NilClass

vendor/bundle/jruby/1.9/gems/gyoku-1.0.0/lib/gyoku/xml_key.rb:5:in `__singleton__' org/jruby/RubyString.java:3037:in `gsub' (
vendor/bundle/jruby/1.9/gems/gyoku-1.0.0/lib/gyoku/xml_key.rb:5:in `__singleton__' org/jruby/RubyProc.java:249:in `call' (
vendor/bundle/jruby/1.9/gems/gyoku-1.0.0/lib/gyoku/xml_key.rb:11:in `__singleton__' org/jruby/RubyProc.java:249:in `call' (
vendor/bundle/jruby/1.9/gems/gyoku-1.0.0/lib/gyoku/xml_key.rb:24:in `create'
vendor/bundle/jruby/1.9/gems/gyoku-1.0.0/lib/gyoku.rb:8:in `xml_tag'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/message.rb:22:in `to_s'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/builder.rb:35:in `to_s' org/jruby/RubyProc.java:249:in `call' (
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:170:in `_nested_structures'
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:63:in `tag!'
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:62:in `tag!'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/builder.rb:35:in `to_s' org/jruby/RubyProc.java:249:in `call' (
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:170:in `_nested_structures'
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:63:in `tag!'
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:62:in `tag!'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/builder.rb:146:in `tag'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/builder.rb:35:in `to_s' org/jruby/RubyProc.java:249:in `call' (
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:170:in `_nested_structures'
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:63:in `tag!'
vendor/bundle/jruby/1.9/gems/builder-3.0.4/lib/builder/xmlbase.rb:62:in `tag!'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/builder.rb:146:in `tag'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/builder.rb:33:in `to_s'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/operation.rb:72:in `build_request'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/operation.rb:48:in `call'
vendor/bundle/jruby/1.9/gems/savon-2.1.0/lib/savon/client.rb:38:in `call'

I'm not exactly sure why this happen, probably the result is not as gyoku expect it but a proper error would be nicer than a NoMethodError.

[rubiii]

can you provide an example hash to reproduce this problem?

[rubiii]

closing this because it can't be reproduced. feel free to reopen if you can provide code or a failing test. thanks.

[fsw0723]

It happens only when we try to make savon requests in threads. Fails for exactly same reason.

[pschambacher]

FYI we're using Savon in threads too.

[anandagrawal84]

@pierre-schambacher did you find the cause of this? How are you managing with it? Its quite intermittent and not reproducible deterministically.

[pschambacher]

@anandagrawal84 we're using this in a pulling system that gets called every few seconds. Since it does not happen very often and since we can miss a call, we haven't done anything. We just get a few errors now and then in NewRelic.

[kafkasbug]

We are getting the same error for a program we use. The following test reproduces the error on jruby 1.7.11 (1.9.3p392):

require 'gyoku'
def convert_all(array)
  array.map{|s| Gyoku.xml_tag s}
end
a = (1..20).map {|i| "hello_world#{i}".to_sym}
threads = (1..200).map do |i|
  Thread.new do
    sleep 1
    convert_all a
  end
end
threads.each {|t| t.join}
puts "all done"

[tjarratt]

Pretty sure I've been able to isolate this to using the $1 global variable here in the key converter. It's pretty clear this isn't thread safe.

My current understanding is that Gyoku makes no attempt at being thread safe, but this seems like a pretty reasonable request to make. The first changes that need to be made are to rewrite the key converters to not use the $1 global variable when using regexes. I'd like to do this myself, but I'm finding that my time is really at a premium these days and I'm unsure when I'll be able to find time.

If someone is interested in issuing a pull request for this, I'd be more than happy to review and merge it!

[perlun]

This thread has some insight into the underlying problem, and why $1 in a lambda/proc is not threadsafe: https://jira.codehaus.org/browse/JRUBY-6754

[tjarratt]

Closing thanks to #46 and d329e39 -- this should be available in Gyoku v1.2.1. Thank you @perlun, @pschambacher and @kafkasbug for raising this issue!