add convenience function to register functions for signals

Author: fvbock

endless.go

@@ -44,6 +44,8 @@ var (
 
  isChild bool
  socketOrder string
+
+ hookableSignals []os.Signal
 )
 
 func init() {
@@ -60,6 +62,15 @@ func init() {
  // after a restart the parent will finish ongoing requests before
  // shutting down. set to a negative value to disable
  DefaultHammerTime = 60 * time.Second
+
+ hookableSignals = []os.Signal{
+ syscall.SIGHUP,
+ syscall.SIGUSR1,
+ syscall.SIGUSR2,
+ syscall.SIGINT,
+ syscall.SIGTERM,
+ syscall.SIGTSTP,
+	}
 }
 
 type endlessServer struct {
@@ -304,12 +315,7 @@ func (srv *endlessServer) handleSignals() {
 
  signal.Notify(
  srv.sigChan,
- syscall.SIGHUP,
- syscall.SIGUSR1,
- syscall.SIGUSR2,
- syscall.SIGINT,
- syscall.SIGTERM,
- syscall.SIGTSTP,
+ hookableSignals...,
 	)
 
  pid := syscall.Getpid()
@@ -412,7 +418,7 @@ func (srv *endlessServer) hammerTime(d time.Duration) {
 func (srv *endlessServer) fork() (err error) {
  // only one server isntance should fork!
  if runningServersForked {
- return errors.New("another fork is running")
+ return errors.New("Another process already forked. Ignoring this one.")
 	}
  runningServerReg.Lock()
  defer runningServerReg.Unlock()
@@ -531,3 +537,23 @@ func (w endlessConn) Close() error {
 	}
  return err
 }
+
+/*
+RegisterSignalHook registers a function to be run PRE_SIGNAL or POST_SIGNAL for
+a given signal. PRE or POST in this case means before or after the signal
+related code endless itself runs
+*/
+func (srv *endlessServer) RegisterSignalHook(prePost int, sig os.Signal, f func()) (err error) {
+ if prePost != PRE_SIGNAL && prePost != POST_SIGNAL {
+ err = fmt.Errorf("Cannot use %v for prePost arg. Must be endless.PRE_SIGNAL or endless.POST_SIGNAL.")
+ return
+	}
+ for _, s := range hookableSignals {
+ if s == sig {
+			srv.SignalHooks[prePost][sig] = append(srv.SignalHooks[prePost][sig], f)
+ return
+		}
+	}
+ err = fmt.Errorf("Signal %v is not supported.")
+ return
+}