caddy/sigtrap.go at master · coderiser/caddy · GitHub

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package caddy

import (

"log"

"os"

"os/signal"

"sync"

)

// TrapSignals create signal handlers for all applicable signals for this

// system. If your Go program uses signals, this is a rather invasive

// function; best to implement them yourself in that case. Signals are not

// required for the caddy package to function properly, but this is a

// convenient way to allow the user to control this part of your program.

func TrapSignals() {

trapSignalsCrossPlatform()

trapSignalsPosix()

}

// trapSignalsCrossPlatform captures SIGINT, which triggers forceful

// shutdown that executes shutdown callbacks first. A second interrupt

// signal will exit the process immediately.

func trapSignalsCrossPlatform() {

go func() {

shutdown := make(chan os.Signal, 1)

signal.Notify(shutdown, os.Interrupt)

for i := 0; true; i++ {

<-shutdown

if i > 0 {

log.Println("[INFO] SIGINT: Force quit")

if PidFile != "" {

os.Remove(PidFile)

}

os.Exit(2)

}

log.Println("[INFO] SIGINT: Shutting down")

if PidFile != "" {

os.Remove(PidFile)

}

go func() {

os.Exit(executeShutdownCallbacks("SIGINT"))

}()

}

}()

}

// executeShutdownCallbacks executes the shutdown callbacks as initiated

// by signame. It logs any errors and returns the recommended exit status.

// This function is idempotent; subsequent invocations always return 0.

func executeShutdownCallbacks(signame string) (exitCode int) {

shutdownCallbacksOnce.Do(func() {

// execute third-party shutdown hooks

EmitEvent(ShutdownEvent, signame)

errs := allShutdownCallbacks()

if len(errs) > 0 {

for _, err := range errs {

log.Printf("[ERROR] %s shutdown: %v", signame, err)

}

exitCode = 4

}

})

return

}

// allShutdownCallbacks executes all the shutdown callbacks

// for all the instances, and returns all the errors generated

// during their execution. An error executing one shutdown

// callback does not stop execution of others. Only one shutdown

// callback is executed at a time.

func allShutdownCallbacks() []error {

var errs []error

instancesMu.Lock()

for _, inst := range instances {

errs = append(errs, inst.ShutdownCallbacks()...)

}

instancesMu.Unlock()

return errs

}

// shutdownCallbacksOnce ensures that shutdown callbacks

// for all instances are only executed once.

var shutdownCallbacksOnce sync.Once

caddy/sigtrap.go at master · coderiser/caddy · GitHub

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