Merge pull request moby#31668 from Microsoft/jjh/nopidfileasservice

Windows: no pidfile when service

cmd/dockerd/docker.go

@@ -74,7 +74,7 @@ func runDaemon(opts daemonOptions) error {
 
 	// On Windows, this may be launching as a service or with an option to
 	// register the service.
-	stop, err := initService(daemonCli)
+	stop, runAsService, err := initService(daemonCli)
 	if err != nil {
 		logrus.Fatal(err)
 	}
@@ -83,6 +83,11 @@ func runDaemon(opts daemonOptions) error {
 		return nil
 	}
 
+	// If Windows SCM manages the service - no need for PID files
+	if runAsService {
+		opts.daemonConfig.Pidfile = ""
+	}
+
 	err = daemonCli.start(opts)
 	notifyShutdown(err)
 	return err

cmd/dockerd/service_unsupported.go

@@ -6,8 +6,8 @@ import (
 	"github.com/spf13/pflag"
 )
 
-func initService(daemonCli *DaemonCli) (bool, error) {
-	return false, nil
+func initService(daemonCli *DaemonCli) (bool, bool, error) {
+	return false, false, nil
 }
 
 func installServiceFlags(flags *pflag.FlagSet) {

cmd/dockerd/service_windows.go

@@ -254,25 +254,28 @@ func unregisterService() error {
 	return nil
 }
 
-func initService(daemonCli *DaemonCli) (bool, error) {
+// initService is the entry point for running the daemon as a Windows
+// service. It returns an indication to stop (if registering/un-registering);
+// an indication of whether it is running as a service; and an error.
+func initService(daemonCli *DaemonCli) (bool, bool, error) {
 	if *flUnregisterService {
 		if *flRegisterService {
-			return true, errors.New("--register-service and --unregister-service cannot be used together")
+			return true, false, errors.New("--register-service and --unregister-service cannot be used together")
 		}
-		return true, unregisterService()
+		return true, false, unregisterService()
 	}
 
 	if *flRegisterService {
-		return true, registerService()
+		return true, false, registerService()
 	}
 
 	if !*flRunService {
-		return false, nil
+		return false, false, nil
 	}
 
 	interactive, err := svc.IsAnInteractiveSession()
 	if err != nil {
-		return false, err
+		return false, false, err
 	}
 
 	h := &handler{
@@ -285,7 +288,7 @@ func initService(daemonCli *DaemonCli) (bool, error) {
 	if !interactive {
 		log, err = eventlog.Open(*flServiceName)
 		if err != nil {
-			return false, err
+			return false, false, err
 		}
 	}
 
@@ -306,9 +309,9 @@ func initService(daemonCli *DaemonCli) (bool, error) {
 	// Wait for the first signal from the service handler.
 	err = <-h.fromsvc
 	if err != nil {
-		return false, err
+		return false, false, err
 	}
-	return false, nil
+	return false, true, nil
 }
 
 func (h *handler) started() error {