Move shutdown kernel code to be within KernelClient

[starskyreverie]

The heart of the code that shuts down the kernel (the API request) should be within KernelClient itself. This way, when the kernel can shut itself done without the help of GatewayClient. This is important in handling the websocket exception, as when we call kernel.shutdown(), we actually want to run the API request to shut down the kernel as well.

Additionally, we should still raise the exception on KernelClient.__init__() if the websocket connection fails, as that way GatewayClient.start_kernel will error out if the connection to the KernelClient isn't working.

[kevin-bates]

Hmm - I guess Python still creates an instance and __init__() isn't like a constructor in Java.

Could we please move the initializing of these 3 attributes to PRIOR to the create_connection call?

[starskyreverie]

Done

[starskyreverie]

Agreed, I was unsure about that too, I'll definitely submit another PR if I notice the thread being an issue

[kevin-bates]

Why were the attribute checks restored? Please see https://github.com/pq43/enterprise_gateway/pull/1 and consider merging it as part of this PR.

[starskyreverie]

Ah I restored them because all tests were failing. I wanted to debug what was going on, I think it has something to do with the response reader thread not being shutdown properly but I'm unsure. The solution in that PR (initializing but only starting the thread after the WS connection) makes a lot of sense though, I didn't realize you could do that as well - thanks!