feat: server middleware graph #67
Conversation
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Marking as draft until Vite shipped it. Ideally, we should also have some logic to hide the tab when running on older vite that does support it. |
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Vite would not expose a public API for server-side related perfs after discussion in vitejs/vite#12787, there is no way for vite-plugin-inspect to get the server start-up time, dependencies scanning time, pre-bundle time... but luckily we can get the middleware resolving time via |
| serverPerf.middleware![url] = [] | ||
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| // @ts-expect-error handle needs 3 or 4 arguments | ||
| await (middlewareArgs.length === 4 ? handle(err, req, res, next) : handle(req, res, next)) |
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Can you help review the middleware timing logic? @sapphi-red @bluwy @patak-dev thanks
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Would you explain a bit more what is self here? I'm lost why it needs to be computed at this point, seems to be the same info you have in total and could check the full array later 🤔
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Consider it as something like self time & total time in cpuprofile. Here total means the middleware execution total time and self equals total minus the next() middleware's total
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Oh, I see. Makes sense, I wasn't clearly thinking in the next() recursion here.
Maybe to avoid race conditions the best would be to avoid computing self until you have the complete array with total times. Only keeping each total is enough, and later you can compute them knowing all the values are there. But this looks good to me 👍🏼
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I got a negative time in the playground after:
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| const total = Date.now() - start | ||
| const metrics = serverPerf.middleware![url] | ||
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| // middleware selfTime = totalTime - next.totalTime |
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Should read prev here, no?
| // middleware selfTime = totalTime - next.totalTime | |
| // middleware selfTime = totalTime - prev.totalTime |
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No, it's next() totalTime, thinking about the onion model.
I met the negative time before, I think it's due to the |
Description
Support showing vite dev server middleware perfs
Linked Issues
This PR depends on vitejs/vite#12787Additional context