chan not receiving SIGTERM from external process handle | Discord Gophers | Page 1

peak gust Sep 27, 2022, 10:16 PM

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I have a go program that is launched from a JS application that keeps a handle on the go process. When I attempt to kill the process with SIGTERM, I never see in the go program's logs that the chan received the signal. Does go not receive signal from external processes? I would presume it does.

mossy thorn Sep 27, 2022, 10:18 PM

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Are you using os/signal?

peak gust Sep 27, 2022, 10:19 PM

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yup

mossy thorn Sep 27, 2022, 10:22 PM

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Can you show how you're handling the signal?

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If you kill it manually do you see it?

peak gust Sep 27, 2022, 10:24 PM

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yup

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sc = make(chan os.Signal)
signal.Notify(sc, syscall.SIGINT, syscall.SIGTERM)
<-sc
conductShutdown()
...
func conductShutdown() {
  println("shutting down server")
  err := dbRunner.Shutdown()
  if err != nil { 
    println(fmt.Sprintf("failed to shutdown database: %s", err.Error()))
  }
}

JS

processHandle?.kill('SIGTERM')

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And yes, when handling it any other way, it does work.

cursive star Sep 27, 2022, 10:33 PM

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wdmym by when handling it any other way ?
can you explain?

mossy thorn Sep 27, 2022, 10:34 PM

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I think you're not sending the signal

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Is processhandle null?

mossy thorn Sep 27, 2022, 10:36 PM

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cursive star wdmym by *when handling it any other way* ? can you explain?

I think they mean by sending the signal by other means

peak gust Sep 27, 2022, 10:58 PM

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Correct, I think the issue lies in SIGTERM, nodejs does not handle SIGTERM on windows but does SIGINT. So I swapped that out and it looks to be working now.

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Also needed to change the make to make(chan os.Signal, 1)

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Actually it still doesnt work lol

timber herald Sep 27, 2022, 11:35 PM

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while windows does use signals, it's not unix, there is no SIGTERM on windows. SIGINT should work tho

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well there is for ANSI compat, but not as you'd expect. You can find more info here https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/signal?view=msvc-170

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also don't use println, especially not println(fmt.Sprintf(...)) use fmt.Println or fmt.Printf

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also note this excerpt from nodejs docs "Windows does not support signals so has no equivalent to termination by signal, but Node.js offers some emulation with process.kill(), and subprocess.kill():" https://nodejs.org/api/process.html. Either way this seems like a node question, not a go one so I'd try my luck with the node community.

#chan not receiving SIGTERM from external process handle