Change httpclient adapter to use thread local variables for thread safety

[tbeauvais]

This fixes a threading issue when doing load testing using webmock for our HttpClient service calls using JRuby. The httpclient_adapter was using shared instance variables which caused response corruption.

Oh I noticed before I even started that there were several spec failures. I looked it to it quickly and noticed that calls http://www.example.com/ now results in 200, with actual content. Is someone looking at that?

[bblimke]

Cheers. One question:

Is there a reason for using non http client specific global variable Thread.current[:webmock_responses]
instead of instance variable @webmock_responses[Thread.current.object_id]

[tbeauvais]

Since that instance variable is shared across threads it's not safe to have simultaneous writes to an Array or Hash. Adding to the hash is not an atomic operation so you could trash the hash even when using different keys.

Make sense?

[bblimke]

I see. Ok that makes sense, cheers. It would be nice to make it at least in part http client specific. Thread.current[:webmock_responses] is very global. It could be as well used by other adapters.

[tbeauvais]

ok, updated...

[bblimke]

I think I have merged it too early. It seems to break http client support in ruby 1.8.7

[tbeauvais]

Ruby 1.8.7, what's that :-) seriously isn't that deprecated? I guess if you really want to still support 1.8.7 you can back out my changes, then when I get a chance I can look into it.

[bblimke]

whether I like it or not 1.8.7 is still supported by WebMock 1.x :)

[bblimke]

I reverted it. It breaks specs in async mode on Ruby 1.8.7. No idea why yet.

[bblimke]

@tbeauvais Just FYI I have re-introduced your excellent solution to the thread safety problem of the httpclient adapter. Thank you! Ruby 1.8.7 is not an issue anymore ;)