handle SIGTERM and SIGINT

pkg/signals/signal.go

@@ -0,0 +1,27 @@
+package signals
+
+import (
+	"os"
+	"os/signal"
+)
+
+var onlyOneSignalHandler = make(chan struct{})
+
+// SetupSignalHandler registered for SIGTERM and SIGINT. A stop channel is returned
+// which is closed on one of these signals. If a second signal is caught, the program
+// is terminated with exit code 1.
+func SetupSignalHandler() (stopCh <-chan struct{}) {
+	close(onlyOneSignalHandler) // panics when called twice
+
+	stop := make(chan struct{})
+	c := make(chan os.Signal, 2)
+	signal.Notify(c, shutdownSignals...)
+	go func() {
+		<-c
+		close(stop)
+		<-c
+		os.Exit(1) // second signal. Exit directly.
+	}()
+
+	return stop
+}

pkg/signals/signal_posix.go

@@ -0,0 +1,10 @@
+// +build !windows
+
+package signals
+
+import (
+	"os"
+	"syscall"
+)
+
+var shutdownSignals = []os.Signal{os.Interrupt, syscall.SIGTERM}

pkg/signals/signal_windows.go

@@ -0,0 +1,7 @@
+package signals
+
+import (
+	"os"
+)
+
+var shutdownSignals = []os.Signal{os.Interrupt}