Support custom timeouts for PB socket #265 [JIRA: CLIENTS-859]

[boosty]

This PR adds support for custom connect, read and write timeouts for the protobuff socket.
The default timeouts by the OS are usually too high for a production app. Smaller timeouts allow the client to try another node more quickly in case of socket problems.

Ported from https://github.com/xing/riak-ruby-client/commit/67f28e1.

[lukebakken]

@boosty I have opened #270 which incorporates your commits and resolves some conflicts. The timeout tests don't always succeed, sometimes the RuntimeError is raised, sometimes not. I'll look into it. Thank you for the PR.

[boosty]

Hi @lukebakken, thanks for the update!
Since I don't have access to your buildbot results, could you let me know which of the tests are flaky (connect, read, write)? We can also continue the discussion in #270.

[boosty]

@lukebakken: Can you get the tests to pass if you lower the timeouts in spec/integration/riak/protobuffs/timeouts_spec.rb from 0.0001 to e.g. 0.00001?

[lukebakken]

read and write are flaky, since they interact with my local Riak node. No matter how low I make the timeout, it's not 100% consistent - apparently my VM is just too fast 😄

I'm just going to code up a simple TCP server for these two tests, like I have here in the Node.js client

[boosty]

Good idea! This way you can slow down the server response as you wish.

Either your system is really too fast, or it might be that the timeout option for IO.select is not equally fine-grained on every system.
I am curious: What setup are you using? I was running the tests successfully on OS X (El Capitan, Ruby 2.3.1) against riak-ruby-vagrant in VirtualBox.

[lukebakken]

I'm running Arch Linux in a Hyper-V VM on Windows 10, with this version of Ruby:

$ ruby --version
ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-linux]

Riak 2.1.4 (built with make locked-deps && make stagedevrel) is running in the same VM. man 2 select shows that it does accept seconds and microseconds, so who knows?