Remove registratation socket file on shutdown

when terminating, remove the *-reg.socket file
created by node-driver-registrar

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

README.md

@@ -76,10 +76,6 @@ the actual driver's name.
           args:
             - "--csi-address=/csi/csi.sock"
             - "--kubelet-registration-path=/var/lib/kubelet/plugins/<drivername.example.com>/csi.sock"
-          lifecycle:
-            preStop:
-              exec:
-                command: ["/bin/sh", "-c", "rm -rf /registration/<plugin> /registration/<drivername.example.com>-reg.sock"]
           volumeMounts:
             - name: plugin-dir
               mountPath: /csi

cmd/csi-node-driver-registrar/node_register.go

@@ -20,22 +20,28 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"os/signal"
 	"runtime"
+	"syscall"
 
 	"google.golang.org/grpc"
 
 	"k8s.io/klog"
 	registerapi "k8s.io/kubernetes/pkg/kubelet/apis/pluginregistration/v1alpha1"
 )
 
+const (
+	sockerDirPath = "/registration"
+)
+
 func nodeRegister(
 	csiDriverName string,
 ) {
 	// When kubeletRegistrationPath is specified then driver-registrar ONLY acts
 	// as gRPC server which replies to registration requests initiated by kubelet's
 	// pluginswatcher infrastructure. Node labeling is done by kubelet's csi code.
 	registrar := newRegistrationServer(csiDriverName, *kubeletRegistrationPath, supportedVersions)
-	socketPath := fmt.Sprintf("/registration/%s-reg.sock", csiDriverName)
+	socketPath := fmt.Sprintf("%s/%s-reg.sock", sockerDirPath, csiDriverName)
 	fi, err := os.Stat(socketPath)
 	if err == nil && (fi.Mode()&os.ModeSocket) != 0 {
 		// Remove any socket, stale or not, but fall through for other files
@@ -69,6 +75,7 @@ func nodeRegister(
 	// Registers kubelet plugin watcher api.
 	registerapi.RegisterRegistrationServer(grpcServer, registrar)
 
+	go removeRegSocket(csiDriverName)
 	// Starts service
 	if err := grpcServer.Serve(lis); err != nil {
 		klog.Errorf("Registration Server stopped serving: %v", err)
@@ -77,3 +84,16 @@ func nodeRegister(
 	// If gRPC server is gracefully shutdown, exit
 	os.Exit(0)
 }
+
+func removeRegSocket(csiDriverName string) {
+	sigc := make(chan os.Signal, 1)
+	signal.Notify(sigc, syscall.SIGTERM)
+	<-sigc
+	socketPath := fmt.Sprintf("%s/%s-reg.sock", sockerDirPath, csiDriverName)
+	err := os.Remove(socketPath)
+	if err != nil && os.IsNotExist(err) {
+		klog.Errorf("failed to remove socket: %s with error: %+v", socketPath, err)
+		os.Exit(1)
+	}
+	os.Exit(0)
+}