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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(1)
}
log.Println("[INFO] SIGINT: Shutting down")
if PidFile != "" {
os.Remove(PidFile)
}
go 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() {
errs := allShutdownCallbacks()
if len(errs) > 0 {
for _, err := range errs {
log.Printf("[ERROR] %s shutdown: %v", signame, err)
}
exitCode = 1
}
})
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
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