service: update API to allow for programs that install their own signal handlers.

service.go

@@ -78,6 +78,9 @@ const (
 	optionUserServiceDefault   = false
 	optionSessionCreate        = "SessionCreate"
 	optionSessionCreateDefault = false
+
+	optionRunWait      = "RunWait"
+	optionReloadSignal = "ReloadSignal"
 )
 
 // Config provides the setup for a Service. The Name field is required.
@@ -106,6 +109,9 @@ type Config struct {
 	//    - RunAtLoad     bool (false)
 	//    - UserService   bool (false) - Install as a current user service.
 	//    - SessionCreate bool (false) - Create a full user session.
+	//  * POSIX
+	//    - RunWait      func() (wait for SIGNAL) - Do not install signal but wait for this function to return.
+	//    - ReloadSignal string () [USR1, ...] - Signal to send on reaload.
 	Option KeyValue
 }
 
@@ -143,7 +149,7 @@ func New(i Interface, c *Config) (Service, error) {
 // more details.
 type KeyValue map[string]interface{}
 
-// Bool returns the value of the given name, assuming the value is a boolean.
+// bool returns the value of the given name, assuming the value is a boolean.
 // If the value isn't found or is not of the type, the defaultValue is returned.
 func (kv KeyValue) bool(name string, defaultValue bool) bool {
 	if v, found := kv[name]; found {
@@ -154,7 +160,7 @@ func (kv KeyValue) bool(name string, defaultValue bool) bool {
 	return defaultValue
 }
 
-// Int returns the value of the given name, assuming the value is an int.
+// int returns the value of the given name, assuming the value is an int.
 // If the value isn't found or is not of the type, the defaultValue is returned.
 func (kv KeyValue) int(name string, defaultValue int) int {
 	if v, found := kv[name]; found {
@@ -165,7 +171,7 @@ func (kv KeyValue) int(name string, defaultValue int) int {
 	return defaultValue
 }
 
-// Int returns the value of the given name, assuming the value is a string.
+// string returns the value of the given name, assuming the value is a string.
 // If the value isn't found or is not of the type, the defaultValue is returned.
 func (kv KeyValue) string(name string, defaultValue string) string {
 	if v, found := kv[name]; found {
@@ -176,7 +182,7 @@ func (kv KeyValue) string(name string, defaultValue string) string {
 	return defaultValue
 }
 
-// Int returns the value of the given name, assuming the value is a float64.
+// float64 returns the value of the given name, assuming the value is a float64.
 // If the value isn't found or is not of the type, the defaultValue is returned.
 func (kv KeyValue) float64(name string, defaultValue float64) float64 {
 	if v, found := kv[name]; found {
@@ -187,6 +193,17 @@ func (kv KeyValue) float64(name string, defaultValue float64) float64 {
 	return defaultValue
 }
 
+// funcSingle returns the value of the given name, assuming the value is a float64.
+// If the value isn't found or is not of the type, the defaultValue is returned.
+func (kv KeyValue) funcSingle(name string, defaultValue func()) func() {
+	if v, found := kv[name]; found {
+		if castValue, is := v.(func()); is {
+			return castValue
+		}
+	}
+	return defaultValue
+}
+
 // Platform returns a description of the system service.
 func Platform() string {
 	if system == nil {

service_darwin.go

@@ -196,11 +196,11 @@ func (s *darwinLaunchdService) Run() error {
 		return err
 	}
 
-	var sigChan = make(chan os.Signal, 3)
-
-	signal.Notify(sigChan, syscall.SIGTERM, os.Interrupt)
-
-	<-sigChan
+	s.Option.funcSingle(optionRunWait, func() {
+		var sigChan = make(chan os.Signal, 3)
+		signal.Notify(sigChan, syscall.SIGTERM, os.Interrupt)
+		<-sigChan
+	})()
 
 	return s.i.Stop(s)
 }

service_systemd_linux.go

@@ -80,9 +80,11 @@ func (s *systemd) Install() error {
 	var to = &struct {
 		*Config
 		Path string
+		ReloadSignal string
 	}{
 		s.Config,
 		path,
+		s.Option.string(optionReloadSignal, ""),
 	}
 
 	err = s.template().Execute(f, to)
@@ -128,11 +130,11 @@ func (s *systemd) Run() (err error) {
 		return err
 	}
 
-	sigChan := make(chan os.Signal, 3)
-
-	signal.Notify(sigChan, syscall.SIGTERM, os.Interrupt)
-
-	<-sigChan
+	s.Option.funcSingle(optionRunWait, func() {
+		var sigChan = make(chan os.Signal, 3)
+		signal.Notify(sigChan, syscall.SIGTERM, os.Interrupt)
+		<-sigChan
+	})()
 
 	return s.i.Stop(s)
 }
@@ -160,6 +162,7 @@ ExecStart={{.Path|cmdEscape}}{{range .Arguments}} {{.|cmd}}{{end}}
 {{if .ChRoot}}RootDirectory={{.ChRoot|cmd}}{{end}}
 {{if .WorkingDirectory}}WorkingDirectory={{.WorkingDirectory|cmd}}{{end}}
 {{if .UserName}}User={{.UserName}}{{end}}
+{{if .ReloadSignal}}ExecReload=/bin/kill -{{.ReloadSignal}} "$MAINPID"{{end}}
 Restart=always
 RestartSec=120
 

service_sysv_linux.go

@@ -127,11 +127,11 @@ func (s *sysv) Run() (err error) {
 		return err
 	}
 
-	sigChan := make(chan os.Signal, 3)
-
-	signal.Notify(sigChan, syscall.SIGTERM, os.Interrupt)
-
-	<-sigChan
+	s.Option.funcSingle(optionRunWait, func() {
+		var sigChan = make(chan os.Signal, 3)
+		signal.Notify(sigChan, syscall.SIGTERM, os.Interrupt)
+		<-sigChan
+	})()
 
 	return s.i.Stop(s)
 }

service_upstart_linux.go

@@ -117,11 +117,11 @@ func (s *upstart) Run() (err error) {
 		return err
 	}
 
-	sigChan := make(chan os.Signal, 3)
-
-	signal.Notify(sigChan, os.Interrupt, os.Kill)
-
-	<-sigChan
+	s.Option.funcSingle(optionRunWait, func() {
+		var sigChan = make(chan os.Signal, 3)
+		signal.Notify(sigChan, os.Interrupt, os.Kill)
+		<-sigChan
+	})()
 
 	return s.i.Stop(s)
 }