This library is not thread safe

[bradrees]

With the increasing popularity of multi-threaded hosts, such as sidekiq and puma, plus the addition of rails 4.0 defaulting to thread-safe mode, it is becoming a limiting factor that this library is not thread safe.

The use of a class variable to store the site and auth token mean that if there are any concurrent requests on different threads these values will be overwritten and chaos may ensue.

I want to raise this issue here also because it has taken quite a while to figure out if the library is thread safe or not - and it's not an easy thing to test reliably. The best I can find is this post: http://ecommerce.shopify.com/c/shopify-apis-and-technology/t/threadsafety-shopify-api-gem-115828 . Reviewing the code and recent changes I believe the issue is still present.

A possible solution could be similar to the answer given in this question, and I'd like to know if this is applicable and a good idea for this library: http://stackoverflow.com/questions/8088126/is-it-thread-safe-to-set-active-resource-http-authentication-on-a-per-user-basis

edited: removed uncertainty - this library is not thread safe. As mentioned in comments ActiveResource has been updated so that the headers are now thread safe, however the session object and base.rb monkey patching still expose the issue.

[kitop]

I came across the same issue.
The problem is in ActiveResource, which already has a pull request for it: rails/activeresource#61

It would be nice to see those patches in the ActiveResource::Base monkey-patchs this gem does.

[guilleiguaran]

Patch merged in ARes

[lastobelus]

+1

[lastobelus]

I don't understand how that patch alone would make us threadsafe. Wouldn't Base.site also have to be made threadsafe?

[bradrees]

Yes, this library is still not thread safe - see my edit of the issue title.

[lastobelus]

I really need to find time to finish shydra

[blutack]

We had a discussion on this [1] and one of the shopify devs has a patched version of shopify_api & ares.

This bug is particularly amusing in light of the new API limits announcement [2].

Pro tip: if you are processing a lot of calls for different shops at the same time,
perform them concurrently instead of one shop after the other!

Pro tip: if you do this with the shopify_api gem, you're going to hit some really nasty & hard to diagnose threading bugs...

1: http://ecommerce.shopify.com/c/shopify-apis-and-technology/t/recommended-library-for-multithreaded-ruby-environment-158053
2: http://ecommerce.shopify.com/c/shopify-apis-and-technology/t/upcoming-change-in-api-limit-calculations-159710

[maartenvg]

This bug is particularly amusing in light of the new API limits announcement [2].

I may have worded it a bit strangely, but I didn't mean concurrently to mean in multiple threads. I meant to alternate your calls to different shops, instead of working off all your calls for one shop before switching over to the next one.

[blutack]

Sorry for the snarkiness - I was frustrated by the confusion surrounding the API limit change.
I do still think however that the word 'concurrently' typically implies multiple concurrent accesses rather than a round-robin approach and don't want any developers less experienced with the shopify_api gem to get caught out; especially given the nasty characteristics of these class of bugs & the new rails4 threading model.
If you wish to reply, it might be better to do so off-issue on the forum thread so we don't spam the issue.

[ponny]

Any ETA on this being resolved?

[chadyj]

This caused a massive problem for us and we hope to see it resolved. In the meantime, thanks to @blutack for providing links to the patched gems.

[maartenvg]

In the new version an option is added to run this threaded. We have a forked version of ActiveResource that stores the class variables in threadlocal variables. Using this forked version will allow ShopifyAPI to be used in a threaded environment.

To enable threadsafety with ShopifyAPI, add the following to your Gemfile:

gem 'activeresource', git: 'git://github.com/Shopify/activeresource', branch: 'threadsafe'
gem 'shopify_api', '>= 3.2.1'

[SebastianSzturo]

I get following error when I want to use @maartenvg solution in sidekiq 3 and rails 4.1.5.
TypeError: can't dup NilClass
Any ideas how I can get shopify_api threadsafe?