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allow forwarding reusePort; use asynctools instead of fork now that PR was merged #278

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to be merged after dom96/httpbeast#47 since it depends on it

@timotheecour timotheecour marked this pull request as ready for review June 27, 2021 22:03
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@@ -495,10 +495,10 @@ proc serve*(
proc (req: httpbeast.Request): Future[void] =
{.gcsafe.}:
result = handleRequest(jes, req),
httpbeast.initSettings(self.settings.port, self.settings.bindAddr)
httpbeast.initSettings(self.settings.port, self.settings.bindAddr, reusePort = self.settings.reusePort)
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Argh, this is quite frustrating. For httpbeast reusePort should be set to true by default by Jester, but then this creates an inconsistency. I guess let's just make reusePort true by default for everything (even asynchttpserver):

reusePort: reusePort,
(I don't like having an Optional here).

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@timotheecour timotheecour Jul 3, 2021

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the default in std/newAsyncHttpServer is reusePort = false; false is the correct default to avoid connections being silently forwarded to the wrong server; this has always been the case since the flag was introduced in nim in 2015; the default should remain false, like we discussed yesterday.
Then everything is consistent betweem std/newAsyncHttpServer, jester, and httpbeast.
For multithread, we can handle this in a second phase to also be consistent there, as dicussed yesterday.

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httpbeast needs to have this enabled by default and hence Jester does too. I don't know what you're suggesting, but if it's to just ignore the false value in httpbeast then I don't think that's right. If someone asks for no reusePort we should give it to them.

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@timotheecour timotheecour Jul 3, 2021

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I don't know what you're suggesting,

we discussed this yesterday:
https://discord.com/channels/371759389889003530/768367394547957761/860630931117965313

  • reusePort is off by default (sane behavior, no impact on performance), so this is consistent with std/newAsyncHttpServer
  • reusePort = true is easy to handle (regardless of numThreads)
  • reusePort = false is easy to handle (with numThreads == 1, regardless of --threads:on|off which user could set for unrelated reasons even if using jester with numThreads = 1)
  • the only tricky case is reusePort = false with numThreads > 1, and we can for now ignore reusePort = false in this case (noting it in docs, as i had done in my httpbeast PR), and in followup work (which I can volunteer to do) honor it as discussed yesterday, by first binding to that port (which would fail if in use) and then running jester threads with resusePort = false.

to which you seemed to have agreed yesterday:

okay, just go for it

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Yes, I know we discussed it yesterday. But I only now realised that this means we are going to ignore reusePort being set to false.

I would prefer to have reusePort set to true in Jester and same for httpbeast by default. Any reason not do this?

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@timotheecour timotheecour Jul 3, 2021

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I only now realised that this means we are going to ignore reusePort being set to false.

that was already the case before this PR, except it was worse because it was ignored for httpbeast but not for useHttpBeast = false; at least with this PR it's honored regardless of useHttpBeast:on|off, so long numThreads = 1

and in the suggested future work, it'll be honored in all cases.

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I would prefer to have reusePort set to true in Jester and same for httpbeast by default. Any reason not do this?

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@timotheecour timotheecour Jul 4, 2021

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The reason is reusePort = false is the saner default, and is also consistent with the setting in std/newAsyncHttpServer, so that when you start a server on an already bound port, you fail fast instead of succeeding and wondering why requests you send to it are not being processed by the server you just launched (or worse, if such requests are sensitive and should only talk to the server you launched).

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you'll already fail fast though via the bind trick though. This might not be the case for asynchttpserver for now (although we can add the same mechanism there as in httpbeast to make it so). I prefer speed by default.

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@timotheecour timotheecour Jul 4, 2021

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you'll already fail fast though via the bind trick though

We shouldn't be subject to TOCTOU if numThreads = 1 (regardless of --threads:on|off), and users shouldn't have to opt-in to get the sane default.

I prefer speed by default.

I don't see why it would impact speed in any way.

Here, I've finally implemented honoring reusePort=false for multithreads, see dom96/httpbeast#50. This should remove any remaining concerns.

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