Add INT and TERM signal handler.

ca/signal.go

@@ -7,6 +7,12 @@ import (
 	"syscall"
 )
 
+// Stopper is the interface that external commands can implement to stop the
+// server.
+type Stopper interface {
+	Stop() error
+}
+
 // StopReloader is the interface that external commands can implement to stop
 // the server and reload the configuration while running.
 type StopReloader interface {
@@ -14,6 +20,32 @@ type StopReloader interface {
 	Reload() error
 }
 
+// StopHandler watches SIGINT, SIGTERM on a list of servers implementing the
+// Stopper interface, and when one of those signals is caught we'll run Stop
+// (SIGINT, SIGTERM) on all servers.
+func StopHandler(servers ...Stopper) {
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
+	defer signal.Stop(signals)
+
+	for {
+		select {
+		case sig := <-signals:
+			switch sig {
+			case syscall.SIGINT, syscall.SIGTERM:
+				log.Println("shutting down ...")
+				for _, server := range servers {
+					err := server.Stop()
+					if err != nil {
+						log.Printf("error stopping server: %s", err.Error())
+					}
+				}
+				return
+			}
+		}
+	}
+}
+
 // StopReloaderHandler watches SIGINT, SIGTERM and SIGHUP on a list of servers
 // implementing the StopReloader interface, and when one of those signals is
 // caught we'll run Stop (SIGINT, SIGTERM) or Reload (SIGHUP) on all servers.