Startup error: kernel file does not exist

[nokome]

I have noticed that on occasions, an error appears no such file or directory, open '/home/guest/.local/share/jupyter/runtime/kernel-d95255e6-2c60-486a-8fb9-e042abd5697e.json in the first code chunk of a document that is using a Python kernel. e.g. https://elife.stencila.io/article-55650/v23/:

I suspect this is a race condition during the startup of the kernel because (a) it does not happen all the time, and (b) on pressing the Run button a second time, the message goes away.

I am unable to replicate the issue locally but seem to get it on CI sometimes. I put a kludge to try to deal with this a few weeks ago:

jupita/src/index.ts

Lines 286 to 290 in f9683d9

	// Wait an arbitrary amount of time for the kernel and
	// messaging to startup. This is an attempt to resolve issues
	// seen on CI where the first test timed out but subsequent tests passed
	// and in production occasionally on first code execution.
	await new Promise((resolve) => setTimeout(resolve, 1000))

.

Perhaps rather than waiting a second we need to either wait for the file to exist via polling or catch the error and retry.