Exceptions in on_message and on_data callbacks are suppressed

[haukot]

Hi,
I found that iodine doesn't handle exceptions raised in on_message and on_data callbacks.

Example app:

class MyChatroom
  def on_message(data)
    raise "SomeError"
  end
end

Iodine::Rack.app = Proc.new do |env|
  unless env['upgrade.websocket?']
    return [404, { 'Content-Type' => 'text/plain' }, ['Not Found']]
  end

  env['upgrade.websocket'] = MyChatroom.new

  [-1, {}, []]
end

Iodine.start

When an exception raised the whole thread gets stuck and no messages are written to the log.
The messages are shown when the server stops, or when all available threads terminate (and the server crashes).

I guess it's because there is direct Ruby C API function call instead of RubyCaller call
https://github.com/boazsegev/iodine/blob/master/ext/iodine/iodine_websockets.c#L683
there should probably be something like this:

RubyCaller.call_arg(handler, iodine_on_message_func_id, 1, &buffer);

[boazsegev]

@haukot ,

Thank you very much for opening this issue!

I guess it's because there is direct Ruby C API function call instead of RubyCaller call

Yes, you're correct.

However, RubyCaller wouldn't help to fix this issue, because the issue is in the RubyCaller implementation.

The best solution is to redesign the RubyCaller implementation so it always protects against exceptions, so it will wrap the code and protect it at this point.

At the moment, RubyCaller only protects against exceptions if the GVL state needs to be updated when entering Ruby code, not when entering C code.

I wrote a fix in the 0.5.0 version branch, I will see if I can back port it to the 0.4.x version branch.

[boazsegev]

I released version 0.4.17 which should solve the issue.

Again, thank you very much for detecting this issue 🙏🏻

[haukot]

Thank you for so fast fix!